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  • 51.
    Carter, Sarah-Sophia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Atif, Abdul Raouf M.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Lanekoff, Ingela
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Improving the biocompatibility of PDMS by improving its curing time and temperature2018Conference paper (Other academic)
  • 52.
    Carter, Sarah-Sophia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Cruz, Javier
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Towards the development of a microfluidic tool to assess the biological properties of biomaterials for bone regeneration2018Conference paper (Refereed)
  • 53.
    Carter, Sarah-Sophia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Nguyen, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Moreira, Milena
    Uppsala University, Science for Life Laboratory, SciLifeLab.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Medical grade titanium on-chip: assessing the biological properties of biomaterials for bone regeneration2019Conference paper (Other academic)
    Abstract [en]

    Medical grade titanium on-chip: assessing the biological properties of biomaterials for bone regeneration

     

    Sarah-Sophia D. Carter1, Hugo Nguyen2, Milena Moreira1, Maria Tenje1, and Gemma Mestres1

    1Department of Engineering Sciences, Science for Life Laboratory, Uppsala University, Sweden

    2Department of Engineering Sciences, Uppsala University, Sweden

     

    Introduction

    Before entering the clinic, biomaterials need to be thoroughly evaluated, which requires accurate in vitro models. In this work, we have developed a microfluidic device that could be used to assess the biological properties of biomaterials, in a more in vivo-like environment than what is currently possible.

     

    Methods

    Our device consists of a polydimethylsiloxane (PDMS, Sylgard 184) microfluidic channel (l= 6 mm, w= 2 mm, h= 200 µm) and a titanium disc (Ti6Al4V, at bottom), held together by an additively manufactured fixture (Fig. 1A). PDMS was cured overnight at 65°C on a silicon wafer master. Once the microchannel and titanium disc were positioned, MC3T3-E1 pre-osteoblast-like cells were seeded (50,000 cells/cm2). After 5 hours incubation under standard culture conditions, flow was started (2 μl/min). As a control, MC3T3-E1 cells were seeded onto plain titanium discs off-chip. Cell viability and morphology were assessed after 20 hours by calcein-AM/propidium iodide (PI), staining live and dead cells respectively.

     

    Results and discussion

    Figure 1B and 1C show calcein-AM/PI stained MC3T3-E1 cells cultured on-chip and figure 1D shows the control, MC3T3-E1 cells cultured off-chip. The potential to culture cells in our chip was confirmed by the presence of a majority of viable cells (green) with a similar morphology as the control sample. The reason for the increased amount of dead cells (red) on-chip compared to the control needs to be further examined, which requires longer-term experiments.

    Conclusion

    We have set the first steps towards a microfluidic tool for the assessment of biological properties of biomaterials.

  • 54.
    Cedervall, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Chalmers Univ Technol, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden.
    Delczeg-Czirjak, Erna Krisztina
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Iusan, Diana
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Pereiro, Manuel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Roy, P.
    Radboud Univ Nijmegen, Inst Mol & Mat, Heyendaalseweg 135, NL-6525 AJ Nijmegen, Netherlands.
    Ericsson, Tore
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Häggström, Lennart
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Lohstroh, W.
    Tech Univ Munich, Heinz Maier Leibnitz Zentrum MLZ, Garching Bei Munchen, Lichtenbergstr, D-185748 Garching, Germany.
    Mutka, H.
    Inst Laue Langevin, BP 156, F-38042 Grenoble 9, France.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Deen, P. P.
    European Spallat Source ESS ERIC, Box 176, SE-22100 Lund, Sweden;Univ Copenhagen, Nanosci Ctr, Niels Bohr Inst, DK-2100 Copenhagen O, Denmark.
    Magnetocaloric effect in Fe2P: Magnetic and phonon degrees of freedom2019In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, no 17, article id 174437Article in journal (Refereed)
    Abstract [en]

    Devices based on magnetocaloric materials provide great hope for environmentally friendly and energy efficient cooling that does not rely on the use of harmful gasses. Fe2P based compounds are alloys that have shown great potential for magnetocaloric devices. The magnetic behavior in Fe2P is characterized by a strong magnetocaloric effect that coexists with a first-order magnetic transition (FOMT). Neutron diffraction and inelastic scattering, Mossbauer spectroscopy, and first-principles calculations have been used to determine the structural and magnetic state of Fe2P around the FOMT. The results reveal that ferromagnetic moments in the ordered phase are perturbed at the FOMT such that the moments cant away from the principle direction within a small temperature region. The acoustic-phonon modes reveal a temperature-dependent nonzero energy gap in the magnetically ordered phase that falls to zero at the FOMT. The interplay between the FOMT and the phonon energy gap indicates hybridization between magnetic modes strongly affected by spin-orbit coupling and phonon modes leading to magnon-phonon quasiparticles that drive the magnetocaloric effect.

  • 55.
    Chabera, Pavel
    et al.
    Lund Univ, Dept Chem, Div Phys Chem, Box 124, SE-22100 Lund, Sweden..
    Liu, Yizhu
    Lund Univ, Dept Chem, CAS, Box 124, SE-22100 Lund, Sweden..
    Prakash, Om
    Lund Univ, Dept Chem, CAS, Box 124, SE-22100 Lund, Sweden..
    Thyrhaug, Erling
    Lund Univ, Dept Chem, Div Phys Chem, Box 124, SE-22100 Lund, Sweden..
    El Nahhas, Amal
    Lund Univ, Dept Chem, Div Phys Chem, Box 124, SE-22100 Lund, Sweden..
    Honarfar, Alireza
    Lund Univ, Dept Chem, Div Phys Chem, Box 124, SE-22100 Lund, Sweden..
    Essen, Sofia
    Lund Univ, Dept Chem, CAS, Box 124, SE-22100 Lund, Sweden..
    Fredin, Lisa A.
    Lund Univ, Dept Chem, Div Theoret Chem, Box 124, SE-22100 Lund, Sweden..
    Harlang, Tobias C. B.
    Lund Univ, Dept Chem, Div Phys Chem, Box 124, SE-22100 Lund, Sweden.;Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark..
    Kjaer, Kasper S.
    Lund Univ, Dept Chem, Div Phys Chem, Box 124, SE-22100 Lund, Sweden.;Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark..
    Handrup, Karsten
    Lund Univ, Dept Phys, Div Synchrotron Radiat Res, Box 118, SE-22100 Lund, Sweden..
    Ericson, Fredric
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Tatsuno, Hideyuki
    Lund Univ, Dept Chem, Div Phys Chem, Box 124, SE-22100 Lund, Sweden..
    Morgan, Kelsey
    NIST, Boulder, CO 80305 USA..
    Schnadt, Joachim
    Lund Univ, Dept Phys, Div Synchrotron Radiat Res, Box 118, SE-22100 Lund, Sweden..
    Häggström, Lennart
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Ericsson, Tore
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Sobkowiak, Adam
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Lidin, Sven
    Lund Univ, Dept Chem, CAS, Box 124, SE-22100 Lund, Sweden..
    Huang, Ping
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Uhlig, Jens
    Lund Univ, Dept Chem, Div Phys Chem, Box 124, SE-22100 Lund, Sweden..
    Bendix, Jesper
    Univ Copenhagen, Dept Chem, Univ Pk 5, DK-2100 Copenhagen, Denmark..
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Sundström, Villy
    Lund Univ, Dept Chem, Div Phys Chem, Box 124, SE-22100 Lund, Sweden..
    Persson, Petter
    Lund Univ, Dept Chem, Div Theoret Chem, Box 124, SE-22100 Lund, Sweden..
    Warnmark, Kenneth
    Lund Univ, Dept Chem, CAS, Box 124, SE-22100 Lund, Sweden..
    A low-spin Fe(III) complex with 100-ps ligand-to-metal charge transfer photoluminescence2017In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 543, no 7647, p. 695-+Article in journal (Refereed)
    Abstract [en]

    Transition-metal complexes are used as photosensitizers(1), in light-emitting diodes, for biosensing and in photocatalysis(2). A key feature in these applications is excitation from the ground state to a charge-transfer state(3,4); the long charge-transfer-state lifetimes typical for complexes of ruthenium(5) and other precious metals are often essential to ensure high performance. There is much interest in replacing these scarce elements with Earth-abundant metals, with iron(6) and copper(7) being particularly attractive owing to their low cost and non-toxicity. But despite the exploration of innovative molecular designs(6,8-10), it remains a formidable scientific challenge(11) to access Earth-abundant transition-metal complexes with long-lived charge-transfer excited states. No known iron complexes are considered(12) photoluminescent at room temperature, and their rapid excited-state deactivation precludes their use as photosensitizers(13-15). Here we present the iron complex [Fe(btz)(3)](3+) (where btz is 3,3'-dimethyl-1,1'-bis(p-tolyl)-4,4'-bis(1,2,3-triazol-5-ylidene)), and show that the superior sigma-donor and pi-acceptor electron properties of the ligand stabilize the excited state sufficiently to realize a long charge-transfer lifetime of 100 picoseconds (ps) and room-temperature photoluminescence. This species is a low-spin Fe(III) d(5) complex, and emission occurs from a long-lived doublet ligand-to-metal charge-transfer ((LMCT)-L-2) state that is rarely seen for transition-metal complexes(4,16,17). The absence of intersystem crossing, which often gives rise to large excited-state energy losses in transition-metal complexes, enables the observation of spin-allowed emission directly to the ground state and could be exploited as an increased driving force in photochemical reactions on surfaces. These findings suggest that appropriate design strategies can deliver new iron-based materials for use as light emitters and photosensitizers.

  • 56.
    Chang, Bo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Shah, Ali
    Aalto University, Finland.
    Zhou, Quan
    Aalto University, Finland.
    HYDROPHILIC-SUPERHYDROPHOBIC PATTERNED SURFACE FOR PARALLEL MICROASSEMBLY2014In: Technical Digest of the 25th Micromechanics and Microsystems Europe Conference (MME 2014), Istanbul, Turkey, 2014, 2014Conference paper (Refereed)
    Abstract [en]

    In  this  paper,  a  hydrophilic-superhydrophobic  patterned  surface  is  investigated for parallel microassembly of 200 µm × 200 µm chips with receptor sites of the same dimensions, allowing for correction of significant error as compared to the state-of-the-art.  The  hydrophilic-superhydrophobic pattered surface consists of 200 µm × 200 µm silicondioxide  receptor  sites  with  black  silicon  substrate coated  with  fluorocarbon  polymer.  The  measured contact  angle  of  water  on  the  silicon  dioxide  padsand the background are 50° and 170°, respectively.The  water  mist-induced  hybrid  microassembly technique  is  used  to  carry  out  the  experimental studies  on  hydrophilic-superhydrophobic  pattered surface  for  parallel  microassembly.  The  experimental results show that the parallel microassembly of  chips  can  not  only  be  achieved  on  hydrophilic-superhydrophobic  patterned  surface,  but  also demonstrate  significant  error  correction  capability. With extreme large initial placement error,  where achip  is  placed  next  to  a receptor  site  and  has  zero overlapping  with  the  receptor  site,  the  chip  is  still able to align with the receptor site. The results also indicate  that  the  reliability  of  the  microassembly process  can  be  greatly  enhanced  using  hydrophilic patterns with super-hydrophobic background.

  • 57.
    Chang, Bo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Shah, Ali
    Aalto University.
    Zhou, Quan
    Aalto University.
    Ras, Robin
    Aalto University.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Self-transport and self-alignment of microchips using microscopic rain2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 14966Article in journal (Refereed)
    Abstract [en]

    Alignment of microchips with receptors is an important process step in the construction of integrated micro- and nanosystems for emerging technologies, and facilitating alignment by spontaneous self-assembly processes is highly desired. Previously, capillary self-alignment of microchips driven by surface tension effects on patterned surfaces has been reported, where it was essential for microchips to have sufficient overlap with receptor sites. Here we demonstrate for the first time capillary self-transport and self-alignment of microchips, where microchips are initially placed outside the corresponding receptor sites and can be self-transported by capillary force to the receptor sites followed by self-alignment. The surface consists of hydrophilic silicon receptor sites surrounded by superhydrophobic black silicon. Rain-induced microscopic droplets are used to form the meniscus for the self-transport and self-alignment. The boundary conditions for the self-transport have been explored by modeling and confirmed experimentally. The maximum permitted gap between a microchip and a receptor site is determined by the volume of the liquid and by the wetting contrast between receptor site and substrate. Microscopic rain applied on hydrophilic-superhydrophobic patterned surfaces greatly improves the capability, reliability and error-tolerance of the process, avoiding the need for accurate initial placement of microchips, and thereby greatly simplifying the alignment process.

  • 58.
    Chang, Bo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Zhou, Quan
    Aalto University, Finland.
    Ras, Robin
    Aalto University, Finland.
    Shah, Ali
    Aalto University, Finland.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sliding droplets on hydrophilic/superhydrophobic patterned surfaces for liquid deposition2016In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 108, no 15, article id 154102Article in journal (Refereed)
    Abstract [en]

    A facile gravity-induced sliding droplets method is reported for deposition of nanoliter sized droplets on hydrophilic/superhydrophobic patterned surface. The deposition process is parallel where multiple different liquids can be deposited simultaneously. The process is also high-throughput, having a great potential to be scaled up by increasing the size of the substrate.

  • 59.
    Chang, Bo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Aalto Univ, Sch Sci, Dept Appl Phys, FI-00076 Aalto, Finland.
    Zhou, Quan
    Aalto Univ, Dept Elect Engn & Automat, FI-00076 Aalto, Finland.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Peoples R China.
    Ras, Robin
    Aalto Univ, Sch Sci, Dept Appl Phys, FI-00076 Aalto, Finland.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Capillary Self-Alignment of Microchips on Soft Substrates2016In: Micromachines, ISSN 2072-666X, E-ISSN 2072-666X, Vol. 7, no 3, article id 41Article in journal (Refereed)
    Abstract [en]

    Soft micro devices and stretchable electronics have attracted great interest for their potential applications in sensory skins and wearable bio-integrated devices. One of the most important steps in building printed circuits is the alignment of assembled micro objects. Previously, the capillary self-alignment of microchips driven by surface tension effects has been shown to be able to achieve high-throughput and high-precision in the integration of micro parts on rigid hydrophilic/superhydrophobic patterned surfaces. In this paper, the self-alignment of microchips on a patterned soft and stretchable substrate, which consists of hydrophilic pads surrounded by a superhydrophobic polydimethylsiloxane (PDMS) background, is demonstrated for the first time. A simple process has been developed for making superhydrophobic soft surface by replicating nanostructures of black silicon onto a PDMS surface. Different kinds of PDMS have been investigated, and the parameters for fabricating superhydrophobic PDMS have been optimized. A self-alignment strategy has been proposed that can result in reliable self-alignment on a soft PDMS substrate. Our results show that capillary self-alignment has great potential for building soft printed circuits.

  • 60.
    Chang, Bo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Zhou, Quan
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ras, Robin
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Superhydrophobic PDMS for capillary self-alignment2016In: 11th Micronano System Workshop (MSW 2016), 2016, Vol. 11, article id P19Conference paper (Refereed)
  • 61. Chansin, G.A.T.
    et al.
    Hong, Jongin
    deMello, A.J.
    Edel, J.B.
    Sharma, G
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Fluorescence detection inside synthetic nanoporous membranes2009Conference paper (Other academic)
  • 62.
    Cheng, Shi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Liquid metal stretchable unbalanced loop antenna2009In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 94, no 14, p. 144103-Article in journal (Refereed)
    Abstract [en]

    We present a 2.4 GHz unbalanced loop antenna that can be stretched along multiple dimensions simultaneously. It was realized by incorporating room temperature liquid metal alloy into microstructured channels in an elastic material. The demonstrated prototype exhibits a stretchability of up to 40% along two orthogonal orientations as well as foldability and twistability. Port impedance and radiation characteristics of the nonstretched and stretched antenna were studied numerically and experimentally. Measured results indicate a radiation efficiency of more than 80%.

  • 63.
    Cheng, Shi
    et al.
    Advanced Technology, Laird Technologies, Kista.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A Microfluidic, Reversibly Stretchable, Large-Area Wireless Strain Sensor2011In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 21, no 12, p. 2282-2290Article in journal (Refereed)
    Abstract [en]

    This article describes the implementation and characterization of a new self-contained large-area wireless strain sensor, operating around 1.5 GHz, based on the concept of multi-layer microfluidic stretchable radiofrequency electronics (mu FSRFEs). Compared to existing solutions, the presented integrated strain sensor is capable of remotely detecting repeated high tensile dynamic strains of up to 15% over very large surfaces or movable parts, and gets rid of all hardwiring to external storage or data processing equipment. Unlike conventional electronic devices, the major part of the sensor is a mechanically reconfigurable and reversibly deformable patch antenna, which consists of two layers of liquid metal alloy filled microfluidic channels in a silicone elastomer. A simplified radiofrequency (RF) transmitter composed of miniaturized rigid active integrated circuits (ICs) associated with discrete passive components was assembled on a flexible printed circuit board (FPCB) and then heterogeneously integrated to the antenna. The elastic patch antenna can withstand repeated mechanical stretches while still maintaining its electrical function to some extent, and return to its original state after removal of the stress. Additionally, its electrical characteristics at frequency of operation are highly sensitive to mechanical strains. Consequently, not only is this antenna a radiator for transmitting and receiving RF signals like any other conventional antennas, but also acts as a reversible large-area strain sensor in the integrated device. Good electrical performance of the standalone antenna and the RF transmitter sub-module was respectively verified by experiments. Furthermore, a personal computer (PC)-assisted RF receiver for receiving and processing the measured data was also designed, implemented, and evaluated. In the real-life demonstration, the integrated strain sensor successfully monitored periodically repeated human body motion, and wirelessly transmitted the measured data to the custom-designed receiver at a distance of 5m in real-time.

  • 64.
    Cheng, Shi
    et al.
    Radio Hardware Division at Ericsson.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidic electronics2012In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 12, no 16, p. 2782-2791Article in journal (Refereed)
    Abstract [en]

    Microfluidics, a field that has been well-established for several decades, has seen extensive applications in the areas of biology, chemistry, and medicine. However, it might be very hard to imagine how such soft microfluidic devices would be used in other areas, such as electronics, in which stiff, solid metals, insulators, and semiconductors have previously dominated. Very recently, things have radically changed. Taking advantage of native properties of microfluidics, advances in microfluidics-based electronics have shown great potential in numerous new appealing applications, e. g. bio-inspired devices, body-worn healthcare and medical sensing systems, and ergonomic units, in which conventional rigid, bulky electronics are facing insurmountable obstacles to fulfil the demand on comfortable user experience. Not only would the birth of microfluidic electronics contribute to both the microfluidics and electronics fields, but it may also shape the future of our daily life. Nevertheless, microfluidic electronics are still at a very early stage, and significant efforts in research and development are needed to advance this emerging field. The intention of this article is to review recent research outcomes in the field of microfluidic electronics, and address current technical challenges and issues. The outlook of future development in microfluidic electronic devices and systems, as well as new fabrication techniques, is also discussed. Moreover, the authors would like to inspire both the microfluidics and electronics communities to further exploit this newly-established field.

  • 65.
    Cheng, Shi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidic Reversibly Stretchable Large-Area Wireless Strain Sensor2011In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 21, no 12, p. 2282-2290Article in journal (Refereed)
  • 66.
    Cheng, Shi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidic stretchable RF electronics2010In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 10, no 23, p. 3227-3234Article in journal (Refereed)
    Abstract [en]

    Stretchable electronics is a revolutionary technology that will potentially create a world of radically different electronic devices and systems that open up an entirely new spectrum of possibilities. This article proposes a microfluidic based solution for stretchable radio frequency (RF) electronics, using hybrid integration of active circuits assembled on flex foils and liquid alloy passive structures embedded in elastic substrates, e. g. polydimethylsiloxane (PDMS). This concept was employed to implement a 900 MHz stretchable RF radiation sensor, consisting of a large area elastic antenna and a cluster of conventional rigid components for RF power detection. The integrated radiation sensor except the power supply was fully embedded in a thin elastomeric substrate. Good electrical performance of the standalone stretchable antenna as well as the RF power detection sub-module was verified by experiments. The sensor successfully detected the RF radiation over 5 m distance in the system demonstration. Experiments on two-dimensional (2D) stretching up to 15%, folding and twisting of the demonstrated sensor were also carried out. Despite the integrated device was severely deformed, no failure in RF radiation sensing was observed in the tests. This technique illuminates a promising route of realizing stretchable and foldable large area integrated RF electronics that are of great interest to a variety of applications like wearable computing, health monitoring, medical diagnostics, and curvilinear electronics.

  • 67.
    Cheng, Shi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hallbjörner, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Foldable and stretchable liquid metal planar inverted cone antenna2009In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 57, no 12, p. 3765-3771Article in journal (Refereed)
    Abstract [en]

    A mechanically flexible planar inverted cone antenna (PICA) for   ultrawideband (UWB) applications is presented. It can be both folded   and stretched significantly without permanent damage or loss of   electrical functionality. The antenna is manufactured with a process in   which conductors are realized by injecting room temperature liquid   metal alloy into micro-structured channels in an elastic dielectric   material. The elastic dielectric material together with the liquid   metal enables bending with a very small radius, twisting, and   stretching along any direction. Port impedance and radiation   characteristics of the non-stretched and stretched antenna are studied   in simulations and experiments. The presented antenna has a return loss   better than 10 dB within 3-11 GHz and a radiation efficiency of > 70%   over 3-10 GHz, also when stretched. Tests verify that stretching up to   40% is possible with maintained electrical performance. The presented   antenna is useful for example for body-worn antennas and in   applications in harsh environments where mechanical flexibility helps   improve durability.

  • 68.
    Cheng, Shi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A highly stretchable microfluidic meandered monopole antenna2009In: 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences µTAS 2009, 2009, p. 1946-1948Conference paper (Refereed)
  • 69.
    Cheng, Shi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Yousef, Hanna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Kratz, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    79 GHz Slot Antennas Based on Substrate Integrated Waveguides (SIW) in a Flexible Printed Circuit Board2009In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 57, no 1, p. 64-71Article in journal (Refereed)
    Abstract [en]

    The design, fabrication and characterization of 79 GHz slot antennas based on substrate integrated waveguides (SIW) are presented in this paper. All the prototypes are fabricated in a polyimide flex foil using printed circuit board (PCB) fabrication processes. A novel concept is used to minimize the leakage losses of the SlWs at millimeter wave frequencies. Different losses in the SlWs are analyzed. SIW-based single slot antenna, longitudinal and four-by-four slot array antennas are numerically and experimentally studied. Measurements of the   antennas show approximately 4.7%, 5.4% and 10.7% impedance bandwidth (S-11 = -10 dB) with 2.8 dBi, 6.0 dBi and 11.0 dBi maximum antenna gain around 79 GHz, respectively. The measured results are in good agreement with the numerical simulations.

  • 70. Cheng, Shi
    et al.
    Öjefors, E.
    Magrell, J.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Inverted-F Antenna for 3D integrated wireless sensor applications2007Conference paper (Refereed)
  • 71.
    Cheng, Shi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group. Signals and systems.
    Öjefors, Erik
    Hallbjörner, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Ogden, Sam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materials Science.
    Magrell, J
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materials Science.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Body surface backed flexible antennas for 17 GHz wireless body area networks sensor applications2007Conference paper (Refereed)
  • 72.
    Cheng, Shi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Öjefors, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Hallbjörner, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Ogden, Sam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Margell, J.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
    Body Surface backed flexible antennas for 17 GHz wireless body area networks sensor applications2007Conference paper (Refereed)
  • 73.
    Cheng, Shi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Öjefors, Erik
    Magrell, J
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Inverted-F antenna for 3D integrated wireless sensor applications2007Conference paper (Refereed)
  • 74.
    Cheng, Shi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Öjefors, Erik
    Ogden, Sam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Gain and efficiency enhanced flip-up antennas for 3D integrated wireless sensor applications2007Conference paper (Refereed)
  • 75.
    Chu, Jiangtao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Influence of Surface Modification and Static Pressure on Microdialysis Protein Extraction Efficiency2015In: 26th Micromechanics and Microsystems Europe Workshop, 2015, p. D8-Conference paper (Other academic)
  • 76.
    Chu, Jiangtao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microdialysis Sampling of Macro Molecules: Fluid Characteristics, Extraction Efficiency and Enhanced Performance2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, fluid characteristics and sampling efficiency of high molecular weight cut-off microdialysis are presented, with the aim of improving the understanding of microdialysis sampling mechanisms and its performance regarding extraction efficiency of biological fluid and biomarkers.

    Microdialysis is a well-established clinical sampling tool for monitoring small biomarkers such as lactate and glucose. In recent years, interest has raised in using high molecular weight cut-off microdialysis to sample macro molecules such as neuropeptides, cytokines and proteins. However, with the increase of the membrane pore size, high molecular weight cut-off microdialysis exhibits drawbacks such like unstable catheter performance, imbalanced fluid recovery, low and unstable molecule extraction efficiency, etc. But still, the fluid characteristics of high molecular weight cut-off microdialysis is rarely studied, and the clinical or in vitro molecule sampling efficiency from recent studies vary from each other and are difficult to compare.  

    Therefore, in this thesis three aspects of high molecular weight cut-off microdialysis have been explored. The first, the fluid characteristics of large pore microdialysis has been investigated, theoretically and experimentally. The results suggest that the experimental fluid recovery is in consistency with its theoretical formula. The second, the macromolecule transport behaviour has been visualized and semi-quantified, using an in vitro test system and fluorescence imaging. The third, two in vitro tests have been done to mimic in vivo cerebrospinal fluid sampling under pressurization, using native and differently surface modified catheters. As results, individual protein/peptide extraction efficiencies were achieved, using targeted mass spectrometry analysis.

    In summary, a theory system of the fluid characteristics of high molecular weight cut-off microdialysis has been built and testified; Macromolecular transport of microdialysis catheter has been visualized; In vivo biomolecules sampling has been simulated by well-defined in vitro studies; Individual biomolecular extraction efficiency has been shown; Different surface modifications of microdialysis catheter have been investigated. It was found that, improved sampling performance can be achieved, in terms of balanced fluid recovery and controlled protein extraction efficiency.

    List of papers
    1. Impact of static pressure on transmembrane fluid exchange in high molecular weight cut off microdialysis
    Open this publication in new window or tab >>Impact of static pressure on transmembrane fluid exchange in high molecular weight cut off microdialysis
    2014 (English)In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 16, no 2, p. 301-310Article in journal (Refereed) Published
    Abstract [en]

    With the interest of studying larger biomolecules by microdialysis (MD), this sampling technique has reached into the ultrafiltration region of fluid exchange, where fluid recovery (FR)  has a strong dependence on pressure. Hence in this study, we focus on the fluid exchange across the high molecular weight cut off MD membrane under the influence of the static pressure in the sampling environment. A theoretical model is presented for MD with such membranes, where FR has a linear dependence upon the static pressure of the sample. Transmembrane (TM) osmotic pressure difference and MD perfusion rate decide how fast FR increases with increased static pressure.

    A test chamber for in vitro MD under static pressure was constructed and validated. It can hold four MD probes under controlled pressurized conditions. Comparison showed good agreement between experiment and theory. Moreover, test results showed that the fluid recovery of the test chamber MD can be set accurately via the chamber pressure, which is controlled by sample injection into the chamber at precise rate. This in vitro system is designed for modelling in vivo MD in cerebrospinal fluid and studies with biological samples in this system may be good models for in vivo MD. 

    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-212726 (URN)10.1007/s10544-013-9833-1 (DOI)000334362000013 ()
    Funder
    Swedish Research Council, P29797-1
    Available from: 2013-12-13 Created: 2013-12-13 Last updated: 2017-12-06Bibliographically approved
    2. Fluorescence imaging of macromolecule transport in high molecular weight cut-off microdialysis
    Open this publication in new window or tab >>Fluorescence imaging of macromolecule transport in high molecular weight cut-off microdialysis
    2014 (English)In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 406, no 29, p. 7601-7609Article in journal (Refereed) Published
    Abstract [en]

    When microdialysis (MD) membrane exceeds molecular weight cut-off (MWCO) of 100 kDa, the fluid mechanics are in the ultrafiltration regime. Consequently, fluidic mass transport of macromolecules in the perfusate over the membrane may reduce the biological relevance of the sampling and cause an inflammatory response in the test subject. Therefore, a method to investigate the molecular transport of high MWCO MD is presented. An in vitro test chamber was fabricated to facilitate the fluorescent imaging of the MD sampling process, using fluoresceinylisothiocyanate (FITC) dextran and fluorescence microscopy. Qualitative studies on dextran behavior inside and outside the membrane were performed. Semiquantitative results showed clear dextran leakage from both 40 and 250 kDa dextran when 100 kDa MWCO membranes were used. Dextran 40 kDa leaked out with an order of magnitude higher concentration and the leakage pattern resembled more of a convective flow pattern compared with dextran 250 kDa, where the leakage pattern was more diffusion based. No leakage was observed when dextran 500 kDa was used as a colloid osmotic agent. The results in this study suggest that fluorescence imaging could be used as a method for qualitative and semiquantitative molecular transport and fluid dynamics studies of MD membranes and other hollow fiber catheter membranes.

    National Category
    Other Medical Engineering Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-239233 (URN)10.1007/s00216-014-8192-y (DOI)000344860300019 ()25286875 (PubMedID)
    Available from: 2014-12-19 Created: 2014-12-19 Last updated: 2017-12-05Bibliographically approved
    3. Influence of surface modification and static pressure on microdialysis protein extraction efficiency
    Open this publication in new window or tab >>Influence of surface modification and static pressure on microdialysis protein extraction efficiency
    Show others...
    2015 (English)In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 17, no 5, article id UNSP 96Article in journal (Refereed) Published
    Abstract [en]

    There is growing interest in using microdialysis (MD) for monitoring larger and more complexmolecules such as neuropeptides and proteins. This promotes the use of MD membranes withmolecular weight cut off (MWCO) of 100 kDa or above. The hydrodynamic property of themembrane goes to ultrafiltration or beyond, making the MD catheters more sensitive to pressure.In the meantime, despite the large pore size, studies have shown that membrane biofouling stilllead to unstable catheter performance. The objective is to study in vitro how 500 kDa dextranand Poloxamer 407 surface modification affect the fluid recovery (FR) and extraction efficiency(EE) of 100 kDa MWCO MD catheters. A pressure chamber was designed to facilitate the tests,using as MD sample a protein standard with similar concentrations as in human cerebral spinalfluid, comparing native and Poloxamer 407 modified MD catheters. The collected dialysatefractions were examined for FR and protein EE, employing Dot-it Spot-it Protein Assay for totalprotein EE and targeted mass spectrometry (MS) for EE of individual proteins and peptides. TheFR results suggested that the surface modified catheters were less sensitive to the pressure andprovide higher precision, and provided a FR closer to 100%. The surface modification did notshow a significant effect on the protein EE. The average total protein EE of surface modifiedcatheters was slightly higher than that of the native ones. The MS EE data of individual proteinsshowed a clear trend of complex response in EE with pressure.

    Place, publisher, year, edition, pages
    Springer: , 2015
    Keywords
    microdialysis, surface modification, poloxamer, protein, extraction efficiency
    National Category
    Nano Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-261031 (URN)10.1007/s10544-015-0005-3 (DOI)000362281200013 ()26342494 (PubMedID)
    Funder
    Berzelii Centre EXSELENTSwedish Research Council, P29797-1Åke Wiberg FoundationMagnus Bergvall FoundationScience for Life Laboratory - a national resource center for high-throughput molecular bioscience
    Available from: 2015-08-28 Created: 2015-08-28 Last updated: 2017-12-04Bibliographically approved
    4. Influence of different pluronic surface modifications and pressure on microdialysis protein extraction efficiency
    Open this publication in new window or tab >>Influence of different pluronic surface modifications and pressure on microdialysis protein extraction efficiency
    Show others...
    2015 (English)In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781Article in journal (Refereed) Submitted
    Abstract [en]

    There is growing interest in using microdialysis (MD) for monitoring larger and more complexmolecules such as neuropeptides and proteins. This promotes the use of MD membranes withmolecular weight cut off (MWCO) of 100 kDa. Hence, the hydrodynamic property of themembrane goes to ultrafiltration, making the sampling more sensitive to pressure changes. Also,despite the large membrane pore size, studies have shown that membrane biofouling still leads tounstable catheter performance. Our objective is to study in vitro how four kinds of surfacemodifications (Pluronic L31, L44, F87 and F127+L31) affect the fluid recovery (FR) andextraction efficiency (EE) of 100 kDa MWCO MD catheters, under controlled pressure. Apressure chamber was employed to facilitate the tests, using as MD sample a protein standardwith proteins of similar concentrations as in human cerebral spinal fluid. The collected dialysatefractions were examined for FR and EE. Targeted mass spectrometry analysed the EE ofindividual proteins and peptides. The thicker the pluronic adsorption layer, the less thehydrodynamic diameter of the membrane pores, leading to lower and more stable FR. The foursurface modifications had three different behaviours: Pluronic F127 + L31 showed similarbehavior to the Pluronic F127 and the native original membrane; Pluronic F87 showed acontinuous EE increase with pressure; Pluronic L31 and L44 showed similar EE values, whichwere stable with pressure. Different surface modifications are clearly selective to differentproteins and peptides. We conclude that a pluronic surface modification could provide MDsampling with more stable FR, and more stable or enhanced EE with high FR, depending on theobjective of the sampling.

    Place, publisher, year, edition, pages
    Springer: , 2015
    Keywords
    microdialysis, surface modification, poloxamer, protein, extraction efficiency
    National Category
    Nano Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology; Engineering Science with specialization in Materials Science
    Identifiers
    urn:nbn:se:uu:diva-261557 (URN)
    Funder
    Berzelii Centre EXSELENT
    Available from: 2015-09-01 Created: 2015-09-01 Last updated: 2017-12-04Bibliographically approved
    5. Protein Desalination Chip for Mass Spectrometry Sample Preparation
    Open this publication in new window or tab >>Protein Desalination Chip for Mass Spectrometry Sample Preparation
    Show others...
    2015 (English)Conference paper, Oral presentation with published abstract (Refereed)
    Abstract [en]

    This work focuses on desalination of a protein sample in a lab-on-chip device using the ion concentration polarization (ICP) technique. It was demonstrated with a salt containing buffer with four proteins and two peptides of concentrations typical to cerebrospinal fluid (CSF). Not only was the output desalinated but its protein concentration with large molecular weight (MW) was as much as 3 times higher for the largest protein compared to the original. We conclude that ICP based microfluidic chips have great potential for desalination and protein concentration in microdialysis sampling coupled to mass spectroscopy (MS).

    Place, publisher, year, edition, pages
    MicroTAS: , 2015
    Keywords
    Ion concentration polarization, Desalination, Protein, Mass spectroscopy
    National Category
    Nano Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology; Engineering Science with specialization in Materials Science
    Identifiers
    urn:nbn:se:uu:diva-261067 (URN)
    Conference
    The 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2015. October 25-29, 2015. Gyeongju, Korea.
    Available from: 2015-08-28 Created: 2015-08-28 Last updated: 2016-01-05
    6. Refined microdialysis method for protein biomarker sampling in acute brain injury in the neurointensive care setting
    Open this publication in new window or tab >>Refined microdialysis method for protein biomarker sampling in acute brain injury in the neurointensive care setting
    Show others...
    2014 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 86, no 17, p. 8671-8679Article in journal (Refereed) Published
    Abstract [en]

    There is growing interest in cerebral microdialysis (MD) for sampling of protein biomarkers in neurointensive care (NIC) patients. Published data point to inherent problems with this methodology including protein interaction and biofouling leading to unstable catheter performance. This study tested the in vivo performance of a refined MD method including catheter surface modification, for protein biomarker sampling in a clinically relevant porcine brain injury model. Seven pigs of both sexes (10-12 weeks old; 22.2-27.3 kg) were included. Mean arterial blood pressure, heart rate, intracranial pressure (ICP) and cerebral perfusion pressure was recorded during the stepwise elevation of intracranial pressure by inflation of an epidural balloon catheter with saline (1 mL/20 min) until brain death. One naïve MD catheter and one surface modified with Pluronic F-127 (10 mm membrane, 100 kDa molecular weight cutoff MD catheter) were inserted into the right frontal cortex and perfused with mock CSF with 3% Dextran 500 at a flow rate of 1.0 μL/min and 20 min sample collection. Naïve catheters showed unstable fluid recovery, sensitive to ICP changes, which was significantly stabilized by surface modification. Three of seven naïve catheters failed to deliver a stable fluid recovery. MD levels of glucose, lactate, pyruvate, glutamate, glycerol and urea measured enzymatically showed an expected gradual ischemic and cellular distress response to the intervention without differences between naïve and surface modified catheters. The 17 most common proteins quantified by iTRAQ and nanoflow LC-MS/MS were used as biomarker models. These proteins showed a significantly more homogeneous response to the ICP intervention in surface modified compared to naïve MD catheters with improved extraction efficiency for most of the proteins. The refined MD method appears to improve the accuracy and precision of protein biomarker sampling in the NIC setting.

    National Category
    Analytical Chemistry Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-232026 (URN)10.1021/ac501880u (DOI)000341229200025 ()25075428 (PubMedID)
    Available from: 2014-09-12 Created: 2014-09-12 Last updated: 2017-12-05Bibliographically approved
    7. Cerebral microdialysis for protein biomarker monitoring in the neurointensive care setting - a technical approach
    Open this publication in new window or tab >>Cerebral microdialysis for protein biomarker monitoring in the neurointensive care setting - a technical approach
    Show others...
    2014 (English)In: Frontiers in Neurology, ISSN 1664-2295, E-ISSN 1664-2295, Vol. 5, p. 245-Article in journal (Refereed) Published
    Abstract [en]

    Cerebral microdialysis (MD) was introduced as a neurochemical monitoring method in the early 1990s and is currently widely used for the sampling of low molecular weight molecules, signaling energy crisis, and cellular distress in the neurointensive care (NIC) setting. There is a growing interest in MD for harvesting of intracerebral protein biomarkers of secondary injury mechanisms in acute traumatic and neurovascular brain injury in the NIC community. The initial enthusiasm over the opportunity to sample protein biomarkers with high molecular weight cut-off MD catheters has dampened somewhat with the emerging realization of inherent methodological problems including protein-protein interaction, protein adhesion, and biofouling, causing an unstable in vivo performance (i.e., fluid recovery and extraction efficiency) of the MD catheter. This review will focus on the results of a multidisciplinary collaborative effort, within the Uppsala Berzelii Centre for Neurodiagnostics during the past several years, to study the features of the complex process of high molecular weight cut-off MD for protein biomarkers. This research has led to new methodology showing robust in vivo performance with optimized fluid recovery and improved extraction efficiency, allowing for more accurate biomarker monitoring. In combination with evolving analytical methodology allowing for multiplex biomarker analysis in ultra-small MD samples, a new opportunity opens up for high-resolution temporal mapping of secondary injury cascades, such as neuroinflammation and other cell injury reactions directly in the injured human brain. Such data may provide an important basis for improved characterization of complex injuries, e.g., traumatic and neurovascular brain injury, and help in defining targets and treatment windows for neuroprotective drug development.

    National Category
    Neurology Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-239227 (URN)10.3389/fneur.2014.00245 (DOI)25520696 (PubMedID)
    Available from: 2014-12-19 Created: 2014-12-19 Last updated: 2017-12-05Bibliographically approved
  • 77.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Larsson, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Consequence of static pressure on transmembrane exchanges during in vitro microdialysis sampling of proteins2012In: Monitoring Molecules in Neuroscience: 14th International Conference, September 16 – 20, London, U.K., 2012Conference paper (Refereed)
  • 78.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Larsson, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Biochemial structure and function.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Impact of static pressure on transmembrane fluid exchange in high molecular weight cut off microdialysis2014In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 16, no 2, p. 301-310Article in journal (Refereed)
    Abstract [en]

    With the interest of studying larger biomolecules by microdialysis (MD), this sampling technique has reached into the ultrafiltration region of fluid exchange, where fluid recovery (FR)  has a strong dependence on pressure. Hence in this study, we focus on the fluid exchange across the high molecular weight cut off MD membrane under the influence of the static pressure in the sampling environment. A theoretical model is presented for MD with such membranes, where FR has a linear dependence upon the static pressure of the sample. Transmembrane (TM) osmotic pressure difference and MD perfusion rate decide how fast FR increases with increased static pressure.

    A test chamber for in vitro MD under static pressure was constructed and validated. It can hold four MD probes under controlled pressurized conditions. Comparison showed good agreement between experiment and theory. Moreover, test results showed that the fluid recovery of the test chamber MD can be set accurately via the chamber pressure, which is controlled by sample injection into the chamber at precise rate. This in vitro system is designed for modelling in vivo MD in cerebrospinal fluid and studies with biological samples in this system may be good models for in vivo MD. 

  • 79.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Koudriavtsev, Vitali
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Analysis of Dextran Leakage across large pore Microdialysis probe by Fluorescent Imaging2013Conference paper (Refereed)
  • 80.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Koudriavtsev, Vitali
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Flourescence imaging of molecule transport in high molecular weight cut-off microdialysis2014Conference paper (Refereed)
  • 81.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Koudriavtsev, Vitali
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Flourescence imaging of molecule transport in high molecular weight cut-off microdialysis2014Conference paper (Refereed)
  • 82.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Koudriavtsev, Vitali
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Fluorescence imaging of macromolecule transport in high molecular weight cut-off microdialysis2014In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 406, no 29, p. 7601-7609Article in journal (Refereed)
    Abstract [en]

    When microdialysis (MD) membrane exceeds molecular weight cut-off (MWCO) of 100 kDa, the fluid mechanics are in the ultrafiltration regime. Consequently, fluidic mass transport of macromolecules in the perfusate over the membrane may reduce the biological relevance of the sampling and cause an inflammatory response in the test subject. Therefore, a method to investigate the molecular transport of high MWCO MD is presented. An in vitro test chamber was fabricated to facilitate the fluorescent imaging of the MD sampling process, using fluoresceinylisothiocyanate (FITC) dextran and fluorescence microscopy. Qualitative studies on dextran behavior inside and outside the membrane were performed. Semiquantitative results showed clear dextran leakage from both 40 and 250 kDa dextran when 100 kDa MWCO membranes were used. Dextran 40 kDa leaked out with an order of magnitude higher concentration and the leakage pattern resembled more of a convective flow pattern compared with dextran 250 kDa, where the leakage pattern was more diffusion based. No leakage was observed when dextran 500 kDa was used as a colloid osmotic agent. The results in this study suggest that fluorescence imaging could be used as a method for qualitative and semiquantitative molecular transport and fluid dynamics studies of MD membranes and other hollow fiber catheter membranes.

  • 83.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Bergström Lind, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Influence of surface modification and static pressure on microdialysis protein extraction efficiency2015In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 17, no 5, article id UNSP 96Article in journal (Refereed)
    Abstract [en]

    There is growing interest in using microdialysis (MD) for monitoring larger and more complexmolecules such as neuropeptides and proteins. This promotes the use of MD membranes withmolecular weight cut off (MWCO) of 100 kDa or above. The hydrodynamic property of themembrane goes to ultrafiltration or beyond, making the MD catheters more sensitive to pressure.In the meantime, despite the large pore size, studies have shown that membrane biofouling stilllead to unstable catheter performance. The objective is to study in vitro how 500 kDa dextranand Poloxamer 407 surface modification affect the fluid recovery (FR) and extraction efficiency(EE) of 100 kDa MWCO MD catheters. A pressure chamber was designed to facilitate the tests,using as MD sample a protein standard with similar concentrations as in human cerebral spinalfluid, comparing native and Poloxamer 407 modified MD catheters. The collected dialysatefractions were examined for FR and protein EE, employing Dot-it Spot-it Protein Assay for totalprotein EE and targeted mass spectrometry (MS) for EE of individual proteins and peptides. TheFR results suggested that the surface modified catheters were less sensitive to the pressure andprovide higher precision, and provided a FR closer to 100%. The surface modification did notshow a significant effect on the protein EE. The average total protein EE of surface modifiedcatheters was slightly higher than that of the native ones. The MS EE data of individual proteinsshowed a clear trend of complex response in EE with pressure.

  • 84.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wang, Cong
    Park, Jungyul
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Protein Desalination Chip for Mass Spectrometry Sample Preparation2015Conference paper (Refereed)
    Abstract [en]

    This work focuses on desalination of a protein sample in a lab-on-chip device using the ion concentration polarization (ICP) technique. It was demonstrated with a salt containing buffer with four proteins and two peptides of concentrations typical to cerebrospinal fluid (CSF). Not only was the output desalinated but its protein concentration with large molecular weight (MW) was as much as 3 times higher for the largest protein compared to the original. We conclude that ICP based microfluidic chips have great potential for desalination and protein concentration in microdialysis sampling coupled to mass spectroscopy (MS).

  • 85.
    Chu, Jiangtao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Lind, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Influence of different pluronic surface modifications and pressure on microdialysis protein extraction efficiency2015In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781Article in journal (Refereed)
    Abstract [en]

    There is growing interest in using microdialysis (MD) for monitoring larger and more complexmolecules such as neuropeptides and proteins. This promotes the use of MD membranes withmolecular weight cut off (MWCO) of 100 kDa. Hence, the hydrodynamic property of themembrane goes to ultrafiltration, making the sampling more sensitive to pressure changes. Also,despite the large membrane pore size, studies have shown that membrane biofouling still leads tounstable catheter performance. Our objective is to study in vitro how four kinds of surfacemodifications (Pluronic L31, L44, F87 and F127+L31) affect the fluid recovery (FR) andextraction efficiency (EE) of 100 kDa MWCO MD catheters, under controlled pressure. Apressure chamber was employed to facilitate the tests, using as MD sample a protein standardwith proteins of similar concentrations as in human cerebral spinal fluid. The collected dialysatefractions were examined for FR and EE. Targeted mass spectrometry analysed the EE ofindividual proteins and peptides. The thicker the pluronic adsorption layer, the less thehydrodynamic diameter of the membrane pores, leading to lower and more stable FR. The foursurface modifications had three different behaviours: Pluronic F127 + L31 showed similarbehavior to the Pluronic F127 and the native original membrane; Pluronic F87 showed acontinuous EE increase with pressure; Pluronic L31 and L44 showed similar EE values, whichwere stable with pressure. Different surface modifications are clearly selective to differentproteins and peptides. We conclude that a pluronic surface modification could provide MDsampling with more stable FR, and more stable or enhanced EE with high FR, depending on theobjective of the sampling.

  • 86.
    Chu, Thi Quy
    et al.
    Hanoi Univ Sci & Technol, Int Training Inst Mat Sci ITIMS, 1 Dai Co Viet, Hanoi, Vietnam.
    Chu, Manh Hung
    Hanoi Univ Sci & Technol, Int Training Inst Mat Sci ITIMS, 1 Dai Co Viet, Hanoi, Vietnam.
    Nguyen, Van Duy
    Hanoi Univ Sci & Technol, Int Training Inst Mat Sci ITIMS, 1 Dai Co Viet, Hanoi, Vietnam.
    Nguyen, Duc Hoa
    Hanoi Univ Sci & Technol, Int Training Inst Mat Sci ITIMS, 1 Dai Co Viet, Hanoi, Vietnam.
    Jiao, Mingzhi
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nguyen, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ethanol-Sensing Characteristics of Nanostructured ZnO: Nanorods, Nanowires, and Porous Nanoparticles2017In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 46, no 6, p. 3406-3411Article in journal (Refereed)
    Abstract [en]

    The morphology and crystalline size of metal oxide-sensing materials arebelieved to have a strong influence on the performance of gas sensors. In thispaper, we report a comparative study on the ethanol-sensing characteristics ofZnO nanorods, nanowires, and porous nanoparticles. The porous ZnOnanoparticles were prepared using a simple thermal decomposition of a sheet-like hydrozincite, whereas the nanorods and nanowires were grown byhydrothermal and chemical vapor deposition methods, respectively. Themorphology and crystal structure of the synthesized materials were charac-terized by field-emission scanning electron microscopy and x-ray diffraction.Ethanol gas-sensing characteristics were systematically studied at differenttemperatures. Our findings show that for ethanol gas-sensing applications,ZnO porous nanoparticles exhibited the best sensitivity, followed by thenanowires and nanorods. Gas-sensing properties were also examined withrespect to the role of crystal growth orientation, crystal size, and porosity.

  • 87.
    Clausen, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Chu, Jiangtao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Kaller, Bodil
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    During, Erik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Marklund, Niklas
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Hillered, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Novel Microdialysis Method to Study The Acute Cytokine Response to Diffuse Traumatic Brain Injury in the Rat2014In: Journal of Neurotrauma, ISSN 0897-7151, E-ISSN 1557-9042, Vol. 31, no 5, p. A19-A19Article in journal (Refereed)
  • 88.
    Cruz, F. Javier
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High pressure inertial focusing for separation and concentration of bacteria at high throughput2017In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, article id UNSP 012001Article in journal (Refereed)
    Abstract [en]

    Inertial focusing is a phenomenon where particles migrate across streamlines in microchannels and focus at well-defined, size dependent equilibrium points of the cross section. It can be taken into advantage for focusing, separation and concentration of particles at high through-put and high efficiency. As particles decrease in size, smaller channels and higher pressures are needed. Hence, new designs are needed to decrease the pressure drop. In this work a novel design was adapted to focus and separate 1 mu m from 3 mu m spherical polystyrene particles. Also 0.5 mu m spherical polystyrene particles were separated, although in a band instead of a single line. The ability to separate, concentrate and focus bacteria, its simplicity of use and high throughput make this technology a candidate for daily routines in laboratories and hospitals.

  • 89.
    Cruz, F. Javier
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High pressure inertial focusing: integration in parallel and series2018Conference paper (Other academic)
  • 90.
    Cruz, Javier
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Graells, Tiscar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Wallden, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Inertial focusing with sub-micron resolution for separation of bacteria2019In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 19, no 7, p. 1257-1266Article in journal (Refereed)
    Abstract [en]

    In this paper, we study inertial focusing in curved channels and demonstrate the alignment of particles with diameters between 0.5 and 2.0 m, a range of biological relevance since it comprises a multitude of bacteria and organelles of eukaryotic cells. The devices offer very sensitive control over the equilibrium positions and allow two modes of operation. In the first, particles having a large variation in size are focused and concentrated together. In the second, the distribution spreads in a range of sizes achieving separation with sub-micron resolution. These systems were validated with three bacteria species (Escherichia coli, Salmonella typhimurium and Klebsiella pneumoniae) showing good alignment while maintaining the viability in all cases. The experiments also revealed that the particles follow a helicoidal trajectory to reach the equilibrium positions, similar to the fluid streamlines simulated in COMSOL, implying that these positions occupy different heights in the cross section. When the equilibrium positions move to the inner wall as the flow rate increases, they are at a similar distance from the centre than in straight channels (approximate to 0.6R), but when the equilibrium positions move to the outer wall as the flow rate increases, they are closer to the centre and the particles pass close to the inner wall to elevate their position before reaching them. These observations were used along with COMSOL simulations to explain the mechanism behind the local force balance and the migration of particles, which we believe contributes to further understanding of the phenomenon. Hopefully, this will make designing more intuitive and reduce the high pressure demands, enabling manipulation of particles much smaller than a micrometer.

  • 91.
    Cruz, Javier
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High pressure inertial focusing for separation and concentration of bacteria at high throughput2017Conference paper (Refereed)
  • 92.
    Cruz, Javier
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hooshmand Zadeh, S
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, China.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Inertial focusing of microparticles and its limitations2016Conference paper (Refereed)
    Abstract [en]

    Microfluidic devices are useful tools for healthcare, biological and chemical analysis and m aterials synthesis amongst fields that can benefit from the unique physics of these systems. In this paper we studied inertial focusing as a tool for hydrodynamic sorting of particles by size. Theory and experimental results are provided as a background for a discussion on how to extend the technology to submicron particles. Different geometries and dimensions of microchannels were designed and simulation data was compared to the experimental results.

  • 93.
    Cruz, Javier
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Walden, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidic sample concentrator2016Conference paper (Refereed)
    Abstract [en]

    We present a rapid, point-of-care microfluidic chip that concentrates water-based samples several orders of magnitude. This reduces the demands of the analysis system and enables the detection of analytes whose concentration would otherwise be lower than the detection limit.

  • 94.
    Cruz, Javier
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Zadeh, S. Hooshmand
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Graells, Tiscar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences. Univ Autonoma Barcelona, Dept Genet & Microbiol, Barcelona, Spain..
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Malmström, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Wu, Zhigang G.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan, Peoples R China..
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High pressure inertial focusing for separating and concentrating bacteria at high throughput2017In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 27, no 8, article id 084001Article in journal (Refereed)
    Abstract [en]

    Inertial focusing is a promising microfluidic technology for concentration and separation of particles by size. However, there is a strong correlation of increased pressure with decreased particle size. Theory and experimental results for larger particles were used to scale down the phenomenon and find the conditions that focus 1 mu m particles. High pressure experiments in robust glass chips were used to demonstrate the alignment. We show how the technique works for 1 mu m spherical polystyrene particles and for Escherichia coli, not being harmful for the bacteria at 50 mu l min(-1). The potential to focus bacteria, simplicity of use and high throughput make this technology interesting for healthcare applications, where concentration and purification of a sample may be required as an initial step.

  • 95.
    Dahlin, Andreas P
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microdialysis sampling of proteins in vitro and in vivo2013Conference paper (Refereed)
  • 96.
    Dahlin, Andreas P.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Protein digestion, like you never seen it before. Identification and quantification of femtomole amounts of proteins adsorbed onto microdialysis membranes using on surface enzymatic digestion (oSED) in conjunction with isobaric tagging, nanoliquid chromatography and tandem mass spectrometry2012Other (Other (popular science, discussion, etc.))
  • 97.
    Dahlin, Andreas P
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hillered, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Sjödin, Marcus O D
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Wetterhall, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Quantification of Proteins Adsorbed to Surface Modified and Non-Modified Microdialysis Membranes using on-Surface Enzymatic Digestion (oSED) iTRAQ-MALDI-TOF/TOF MS2012In: 60th ASMS Conference on Mass Spectrometry and Allied Topics, May 20 - 24, Vancouver, Canada, 2012Conference paper (Refereed)
  • 98.
    Dahlin, Andreas P
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hillered, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Sjödin, Marcus O.D.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Wetterhall, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Multiplexed quantification of proteins adsorbed to surface-modified and non-modified microdialysis membranes2012In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 402, no 6, p. 2057-2067Article in journal (Refereed)
    Abstract [en]

    A simple and straightforward method for discovery and quantification of proteins adsorbed onto delicate and sensitive membrane surfaces is presented. The adsorbed proteins were enzymatically cleaved while still adsorbed onto the membranes using an on-surface enzymatic digestion (oSED). This was followed by isobaric tagging, nanoliquid chromatography, and tandem mass spectrometry. Protein adsorption on tri-block copolymer Poloxamer 407 surface-modified microdialysis (MD) membranes were compared with protein adsorption on unmodified MD membranes. Ventricular cerebrospinal fluid (vCSF) kept at 37 °C was used as sample matrix. In total, 19 proteins were quantified in two biological replicates. The surface-modified membranes adsorbed 33% less proteins than control membranes and the most abundant proteins were subunits of hemoglobin and clusterin. The adsorption of clusterin on the modified membranes was on average 36% compared to control membranes. The most common protein in vCSF, Albumin, was not identified adsorbed to the surface at all. It was also experimentally verified that oSED, in conjunction with tandem mass spectrometry can be used to quantify femtomole amounts of proteins adsorbed on limited and delicate surfaces, such as MD membranes. The method has great potential and can be used to study much more complex protein adsorption systems than previously reported.

  • 99.
    Dahlin, Andreas P
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Purins, Karlis
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Clausen, Fredrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Chu, Jiangtao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sedigh, Amir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Transplantation Surgery.
    Lorant, Tomas
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Transplantation Surgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Hillered, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Refined microdialysis method for protein biomarker sampling in acute brain injury in the neurointensive care setting2014In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 86, no 17, p. 8671-8679Article in journal (Refereed)
    Abstract [en]

    There is growing interest in cerebral microdialysis (MD) for sampling of protein biomarkers in neurointensive care (NIC) patients. Published data point to inherent problems with this methodology including protein interaction and biofouling leading to unstable catheter performance. This study tested the in vivo performance of a refined MD method including catheter surface modification, for protein biomarker sampling in a clinically relevant porcine brain injury model. Seven pigs of both sexes (10-12 weeks old; 22.2-27.3 kg) were included. Mean arterial blood pressure, heart rate, intracranial pressure (ICP) and cerebral perfusion pressure was recorded during the stepwise elevation of intracranial pressure by inflation of an epidural balloon catheter with saline (1 mL/20 min) until brain death. One naïve MD catheter and one surface modified with Pluronic F-127 (10 mm membrane, 100 kDa molecular weight cutoff MD catheter) were inserted into the right frontal cortex and perfused with mock CSF with 3% Dextran 500 at a flow rate of 1.0 μL/min and 20 min sample collection. Naïve catheters showed unstable fluid recovery, sensitive to ICP changes, which was significantly stabilized by surface modification. Three of seven naïve catheters failed to deliver a stable fluid recovery. MD levels of glucose, lactate, pyruvate, glutamate, glycerol and urea measured enzymatically showed an expected gradual ischemic and cellular distress response to the intervention without differences between naïve and surface modified catheters. The 17 most common proteins quantified by iTRAQ and nanoflow LC-MS/MS were used as biomarker models. These proteins showed a significantly more homogeneous response to the ICP intervention in surface modified compared to naïve MD catheters with improved extraction efficiency for most of the proteins. The refined MD method appears to improve the accuracy and precision of protein biomarker sampling in the NIC setting.

  • 100.
    Dahlin, Andreas P
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Purins, Karlis
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lewen, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Hillered, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Improved Microdialysis Sampling of Proteins using Surface Modified Catheters: An in vivo Study in Standardized Pig Brain Death Model2013Conference paper (Refereed)
1234567 51 - 100 of 555
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