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  • 101.
    Dahlin, Andreas P
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Purins, Karlis
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap, Neurokirurgi.
    Lewen, Anders
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap, Neurokirurgi.
    Hillered, Lars
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap, Neurokirurgi.
    Improved Microdialysis Sampling of Proteins using Surface Modified Catheters: An in vivo Study in Standardized Pig Brain Death Model2013Konferensbidrag (Refereegranskat)
  • 102.
    Dahlin, Andreas P.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Wetterhall, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Caldwell, Karin D.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Larsson, Anders
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper, Klinisk kemi.
    Bergquist, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Hillered, Lars
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap, Neurokirurgi.
    Hjort, Klas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Methodological aspects on microdialysis protein sampling and quantification in biological fluids: an in vitro study on human ventricular CSF.2010Ingår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 82, nr 11, s. 4376-4385Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is growing interest in sampling of protein biomarkers from the interstitial compartment of the brain and other organs using high molecular cutoff membrane microdialysis (MD) catheters. However, recent data suggest that protein sampling across such MD membranes is a highly complex process that needs to be further studied. Here, we report three major improvements for microdialysis sampling of proteins in complex biological matrixes. The improvements in this in vitro study using human ventricular cerebrospinal fluid as the sample matrix include increased fluid recovery control, decreased protein adsorption on the microdialysis membrane and materials, and novel quantitative mass spectrometry analysis. Dextrans in different concentrations and sizes were added to the perfusion fluid. It was found that dextrans with molecular mass 250 and 500 kDa provided a fluid recovery close to 100%. An improved fluid recovery precision could be obtained by self-assembly triblock polymer surface modification of the MD catheters. The modified catheters also delivered a significantly increased extraction efficiency for some of the investigated proteins. The final improvement was to analyze the dialysates with isobaric tagged (iTRAQ) proteomics, followed by tandem mass spectrometric analysis. By using this technique, 48 proteins could be quantified and analyzed with respect to their extraction efficiencies. The novel aspects of microdialysis protein sampling, detection, and quantification in biological fluids presented in this study should be considered as a first step toward better understanding and handling of the challenges associated with microdialysis sampling of proteins. The next step is to optimize the developed methodology in vivo.

  • 103.
    Dancila, Dragos
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Hoang Duc, Long
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Jobs, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Holmberg, Måns
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    Hjort, Adam
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Rydberg, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ruber, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, FREIA.
    A compact 10 kW solid-state RF power amplifier at 352 MHz2017Konferensbidrag (Refereegranskat)
  • 104.
    Darwish, Nasser
    et al.
    Universitat de Barcelona, Spain.
    Moreno, Mauricio
    Universitat de Barcelona, Spain.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Samitier, Josep
    Universitat de Barcelona, Spain.
    Nikolajeff, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Surface plasmon resonance using nanocrystaline diamond substrates2010Konferensbidrag (Refereegranskat)
  • 105.
    Delacroix, Christian
    et al.
    Hololab, Université de Liège.
    Absil, Olivier
    IAGL, Université de Liège.
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Mawet, Dimitri
    European Southern Observatory.
    Christiaens, Valentin
    IAGL, Université de Liège.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Boccaletti, Anthony
    LESIA-Observatoire de Paris.
    Baudoz, Pierre
    LESIA-Observatoire de Paris.
    Kuittinen, Markku
    Department of Physics and Mathematics, University of Eastern Finland.
    Vartiainen, Ismo
    Paul Scherrer Institut.
    Surdej, Jean
    IAGL, Université de Liège.
    Habraken, Serge
    IAGL, Université de Liège.
    Laboratory demonstration of a mid-infrared AGPM vector vortex coronagraph2013Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 553, s. A98-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context. Coronagraphy is a powerful technique to achieve high contrast imaging, hence to image faint companions around bright targets. Various concepts have been used in the visible and near-infrared regimes, while coronagraphic applications in the mid-infrared nowadays remain largely unexplored. Vector vortex phase masks based on concentric subwavelength gratings show great promise for such applications.

    Aims. We aim at producing and validating the first high-performance broadband focal plane phase mask coronagraphs for applications in the mid-infrared regime, and in particular the L band with a fractional bandwidth of  ~16% (3.5–4.1 μm).

    Methods. Based on rigorous coupled wave analysis, we designed an annular groove phase mask (AGPM) producing a vortex effect in the L band, and etched it onto a series of diamond substrates. The grating parameters were measured by means of scanning electron microscopy. The resulting components were then tested on a mid-infrared coronagraphic test bench.

    Results. A broadband raw null depth of 2 × 10-3 was obtained for our best L-band AGPM after only a few iterations between design and manufacturing. This corresponds to a raw contrast of about 6 × 10-5 (10.5 mag) at 2λ/D. This result is fully in line with our projections based on rigorous coupled wave analysis modelling, using the measured grating parameters. The sensitivity to tilt and focus has also been evaluated.

    Conclusions. After years of technological developments, mid-infrared vector vortex coronagraphs have finally become a reality and live up to our expectations. Based on their measured performance, our L-band AGPMs are now ready to open a new parameter space in exoplanet imaging at major ground-based observatories.

  • 106.
    Delacroix, Christian
    et al.
    Hololab, Université de Liège, Belgien.
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Mawet, Dimitri
    European Southern Observatory (ESO), Santiago, Chile.
    Absil, Olivier
    IAGL, Université de Liège, Belgien.
    Hanot, Charles
    IAGL, Université de Liège, Belgien.
    Surdej, Jean
    IAGL, Université de Liège, Belgien.
    Habraken, Serge
    Hololab, Université de Liège, Belgien.
    Design, manufacturing, and performance analysis of mid-infrared achromatic half-wave plates with diamond subwavelength gratings2012Ingår i: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 51, nr 24, s. 5897-5902Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we present a solution for creating robust monolithic achromatic half-wave plates (HWPs) for the infrared, based on the form birefringence of subwavelength gratings (SWGs) made out of diamond. We use the rigorous coupled wave analysis to design the gratings. Our analysis shows that diamond, besides its outstanding physical and mechanical properties, is a suitable substrate to manufacture mid-infrared HWPs, thanks to its high refractive index, which allows etching SWGs with lower aspect ratio. Based on our optimized design, we manufactured a diamond HWP for the 11-13.2 mu m region, with an estimated mean retardance similar to 3.143 +/- 0.061 rad ( 180.08 +/- 3.51 degrees). In addition, an antireflective grating was etched on the backside of the wave plate, allowing a total transmittance between 89% and 95% over the band.

  • 107.
    Delacroix, Christian
    et al.
    Université de Liège, Belgium.
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Mawet, Dimitri
    European Southern Observatory, Chile.
    Lenaerts, Cedric
    Université de Liège, Belgium.
    Habraken, Serge
    Université de Liège, Belgium.
    Absil, Olivier
    Université de Liège, Belgium.
    Hanot, Charles
    Université de Liège, Belgium.
    Surdej, Jean
    Université de Liège, Belgium.
    First manufactured diamond AGPM vector vortex for the L- and N- bands: metrology and expected performances2010Konferensbidrag (Refereegranskat)
  • 108.
    Delacroix, Christian
    et al.
    Université de Liège, Belgium.
    Habraken, Serge
    Université de Liège, Belgium.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Absil, Olivier
    Université de Liège, Belgium.
    Hanot, Charles
    Université de Liège, Belgium.
    Surdej, Jean
    Université de Liège, Belgium.
    Mawet, Dimitri
    European Southern Observatory, Chile.
    Development of diamond AGPM coronagraphs for VISIR and NACO2012Konferensbidrag (Refereegranskat)
  • 109.
    Delacroix, Christian
    et al.
    Université de Liège, Belgium.
    Habraken, Serge
    Université de Liège, Belgium.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Nikolajeff, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Diamond subwavelength gratings for mid-infrared diamond AGPM coronagraph: manufacturing assessment2010Konferensbidrag (Refereegranskat)
  • 110.
    Delacroix, Christian
    et al.
    Liège University, Hololab Group.
    Habraken, Serge
    Liège University, Hololab Group.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Nikolajeff, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Diamond subwavelength gratings for mid-infrared diamond AGPM coronagraph: manufacturing assessment2010Ingår i: EOSAM 2010, Paris, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present the manufacturing and measurement results obtained with a mid-infrared (L- band ~ 3.8 μm) diamond Annular Groove Phase Mask (AGPM) coronagraph (Mawet et al 20051), using subwavelength gratings and diamond-optimized micro-fabrication techniques such as Nano-Imprint Lithography and Reactive Ion Etching.

     

  • 111.
    D’Elía, Noelia L.
    et al.
    Universidad Nacional del Sur, Argentina.
    Rial Silva, Ramon
    Universidad Santiago de Compostela, Spain.
    Sartuqui, Javier
    Universidad Nacional del Sur, Argentina.
    Ercoli, Daniel
    Planta Piloto de Ingeniería Química – PLAPIQUI (UNS-CONICET), Argentina.
    Ruso, Juan
    Universidad Santiago de Compostela, Spain.
    Messina, Paula
    Universidad Nacional del Sur, Argentina.
    Mestres, Gemma
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Alginate - hydroxyapatite composites for guided bone regeneration: rheology and tensile strength2019Konferensbidrag (Övrigt vetenskapligt)
  • 112.
    Deng, Pan
    et al.
    Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan, Hubei, Peoples R China.
    Fu, Cheng-Jie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Systematisk biologi.
    Wu, Zhigang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan, Hubei, Peoples R China.
    High purity and viability cell separation of a bacterivorous jakobid flagellate based on a steep velocity gradient induced soft inertial force2018Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, nr 62, s. 35512-35520Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cell separation is one of the key limiting factors for precise analysis of non-axenic microbial lab cultures or environmental samples, and it remains a challenge to isolate target cells with high purity and viability via high-throughput cell sorting. During the past decade, hydrodynamic microfluidic platforms have attracted great attention in cell preparation for their high efficiency, robust performance and low cost. Here, we employ the use of a low-velocity sheath flow with high viscosity near the wall and a high-velocity sheath flow with low viscosity on the other side of the sample flow in a soft inertial separation chip. This not only prevents hard interactions between cells and chip walls but, in comparison to previous inertial separation methods, generates a significant increase in deflection of large cells while keeping the small ones in the original flow. We first conducted experiments on a mixture of small and large fluorescent particles (1.0 and 9.9 m, respectively) and removed over 99% of the small particles. The separation efficiency was then tested on a culture of a bacterivorous jakobid flagellate, Seculamonas ecuadoriensis fed on the live bacterium, Klebsiella sp. Using our microfluidic chip, over 94% of live bacteria were removed while maintaining high jakobid cell viability. For comparison, we also conducted size-based cell sorting of the same culture using flow cytometry, which is widely used as a rapid and automated separation tool. Compared with the latter, our chip showed more than 40% higher separation efficiency. Thus, our device provides high purity and viability for cell separation of a sensitive cell sample (jakobid cells). Potentially, the method can be further used for applications in diagnostics, biological analyses and environmental assessment of mixed microbial samples.

  • 113.
    Diez-Escudero, Anna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Liu, Yuling
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Lançon, Victorine
    KTH Royal Institute of Technology, Stockholm.
    Widhe, Mona
    KTH Royal Institute of Technology, Stockholm.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Hedhammar, My
    KTH Royal Institute of Technology, Stockholm.
    Mestres, Gemma
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Recombinant silk with calcium phosphates as macroporous bone scaffolds2019Konferensbidrag (Refereegranskat)
  • 114. Duoc, Vo Thanh
    et al.
    Le, Dang Thi Thanh
    Hoa, Nguyen Duc
    Duy, Nguyen Van
    Hung, Chu Manh
    Nguyen, Hugo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Phenikaa Research and Technology Institute (PRATI), A&A Green Phoenix Group, 167 Hoang Ngan, Hanoi 100000, Vietnam.
    Hieu, Nguyen Van
    New Design of ZnO Nanorod- and Nanowire-Based NO2 Room-Temperature Sensors Prepared by Hydrothermal Method2019Ingår i: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, artikel-id 6821937Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Room-temperature gas sensors are attracting attention because of their low power consumption, safe operation, and long-term stability. Herein, ZnO nanorods (NRs) and nanowires (NWs) were on-chip grown via a facile hydrothermal method and used for room-temperature NO2 gas sensor applications. The ZnO NRs were obtained by a one-step hydrothermal process, whereas the NWs were obtained by a two-step hydrothermal process. To obtain ZnO NW sensor, the length of NRs was controlled short enough so that none of the nanorod-nanorod junction was made. Thereafter, the NWs were grown from the tips of no-contact NRs to form nanowire-nanowire junctions. The gas-sensing characteristics of ZnO NRs and NWs were tested against NO2 gas at room temperature for comparison. The gas-sensing characteristics of the sensors were also tested at different applied voltages to evaluate the effect of the self-activated gas-sensing performance. Results show that the diameter of ZnO NRs and NWs is the dominant parameter of their NO2 gas-sensing performance at room temperature. In addition, self-activation by local heating occurred for both sensors, but because the NWs were smaller and sparser than the NRs, local heating thus required a lower applied voltage with maximal response compared with the NRs.

  • 115.
    Edqvist, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Corradi, Paolo
    Center for Applied Research in Micro Engineering, Scuola Superiore Sant’Anna, Pontedera, Italy.
    A vibrating microcantilever sensor for microrobotic applicationsIngår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to actively interact with the environment and to perform advanced tasks, microrobots need to be equipped with sensing tools to detect object and obstacles, and eventually manipulate and transport micro-parts. The concept, design, simulations and first characterization of a simple multifunctional microsystem, a vibrating microcantilever, capable of working as touch sensor and potentially as manipulation tool with feedback sensing is presented. The presented microcantilever was designed to be integrated onboard a microrobot of about 3 × 3 × 3 mm3. The microcantilever is applied as a sensing antenna on the microrobot in order to recognize objects or obstacles through direct contact, causing a voltage drop in a feedback layer. The microcantilever produced is 2.85×0.45×0.098 mm, and the experiments verified that it could be used as a contact sensor featuring high sensitivity with extremely low power consumption and good mass-manufacturability.

  • 116.
    Edqvist, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Hedlund, Emma
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Design and manufacturing considerations of low voltage multilayer P(VDF-TrFE) actuators2009Ingår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 19, nr 11, s. 115019-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An actuator unit consisting of three multilayered cantilevers with poly(vinylidene fluoride-trifluoroethylene) on top of a flexible printed circuit board substrate is presented. The multilayer structure has five active polymer layers and six electrodes with an alternating ground and phase configuration. Different aspects regarding processing and deflection advantages, depending on which side of the substrate the multilayer structure is manufactured, are discussed.  One of the cantilever configurations is dynamically modelled using a finite element software and the results are compared to measured values. Because of the combination of a multilayer design and the resonant driving mode, the actuators could be powered by solar cells or used in portable electronics. A 2 V sine wave signal resulted in a tip deflection of 56 μm. To test the unit as a conveyer, speed measurements were conducted. With a 2.5 V square wave signal the speed was 29 µm/s whereas a 8 V signal resulted in 732 µm/s. Motion in all four directions could be confirmed by tuning the frequency of a 10 V square wave signal from 640 Hz to 740 Hz.

  • 117.
    Edqvist, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Hedlund, Emma
    Resonating low voltage P(VDF-TrFE) multilayered microactuator built on flexible printed circuit boardIngår i: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A resonating low voltage microactuator module is presented and evaluated as conveyer. The characterized module has four cantilevers, of which three are used as legs and one as a sensor. A lithographically patterned flexible printed circuit board acts as the passive part of the cantilever whereas the active part consist of 14 layers of spin coated poly(vinylidenefluoride-trifluoroethylene) with alternating evaporated aluminum electrodes. Among the process steps developed are: a batchwise contacting of the multilayer stack, a batchwise polarization method, and an extended polarization procedure. In the final manufacturing step, the legs are bent 60° out of the plane using a folding equipment. The locomotion module is characterized by connecting it with four copper wires and tested with the legs downwards and upside down against a glass plate. Different weights are added to the module and different driving voltage levels and frequencies are tested. The module was found to operate already at 3.0 V peak-to-peak and capable of forward, backward, right and left movement. With wires attached to it, and using a 80 V peak-to-peak square wave signal at 18020 Hz, it could move 150 mg, which is more than 37 times it own weight.

  • 118.
    Edqvist, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Hedlund, Emma
    Lundberg, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Quasi-static and dynamic electromechanical response of piezoelectric multilayer cantilever beams2010Ingår i: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 157, nr 2, s. 198-209Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Piezoelectric multilayer cantilever beams were considered with the aim to establish a simple but general theoretical model, fabricate such beams by a procedure suitable for devices on millimetre scale such as actuators, and study their quasi-static and dynamic electro-mechanical responses. In addition to Euler-Bernoulli assumptions, the beams were assumed to be lossless and have linear piezoelectric response. Four types of beams of nominal length 10 mm, width 2 mm and thickness either 55 or 86 µm, and with two asymmetric configurations of 14 or 15 layers, were fabricated. From top to bottom, each beam consisted of six aluminium electrode layers alternating with five active P(VDF-TrFE) layers, of one passive such layer, and of one polyimide and one copper layer, or vice versa. The thicknesses of the layers and of the beam were determined by use of focused ion beam, scanning electron microscope, light microscope, and Heidenhain probe. Both theoretical and experimental results for resonance frequencies and transverse tip displacement per unit driving voltage showed fair overall agreement from quasi-static conditions to frequencies above the second resonance frequency. Deviations observed are mainly due to variations resulting from the manufacturing process, to nonlinear piezoelectricity and to the presence of losses.

  • 119.
    Edqvist, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Snis, Niklas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Casanova Mohr, Raimon
    SiC, Electronics Department, University of Barcelona, Barcelona, Spain.
    Scholz, Oliver
    IBMT, Fraunhofer Institute for Biomedical Engineering, St Ingbert, Germany.
    Corradi, Paolo
    Scuola Superiore Sant’Anna, Pisa, Italy.
    Gao, Jianbo
    IBMT, Fraunhofer Institute for Biomedical Engineering, St Ingbert, Germany.
    Di´eguez, Angel
    SiC, Electronics Department, University of Barcelona, Barcelona, Spain.
    Wyrsch, Nicolas
    Institut de Microtechnique, University of Neuchˆatel, Neuchˆatel, Switzerland.
    Johansson, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Evaluation of building technology for mass producible millimetre-sized robots using flexible printed circuit boards2009Ingår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 19, nr 7, s. 11pp-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Initial tests of a building technology for a compact three-dimensional mass produciblemicrorobot are presented. The 3.9 × 3.9 × 3.3 mm3 sized prototype robot represents amicrosystem with actuators, sensors, energy management and integrated electronics. Theweight of a folded robot is 65 mg and the total volume is less than 23 mm3. The design of theinterfaces of the different modules in the robot, as well as the building technology, isdescribed. The modules are assembled using conductive adhesive with industrial surfacemounting technology on a thin double-sided flexible printed circuit board. The final shape ofthe microrobots is achieved by folding the flexible printed circuit board twice. Electrical andmechanical studies are performed to evaluate the assembly and it is concluded that thetechnology can be used for this type of microsystem. Several issues using the presentedassembly technique are identified and addressed.

  • 120.
    Eklund, Melika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Kjäll, Nellie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Silicone-based Carbon Black Composite for Epidermal Electrodes2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    A method of synthesizing silicone-based composite consisting of carbon black

    (CB) as a conductive ller in Polydimethylsiloxane (PDMS) was developed.

    The aim was to nd a cost eective and easier method to fabricate stretchable,

    epidermal and conductive electrodes in striving for inexpensive real-time health

    monitoring. In this work, instead of expensive additive materials for enhancement

    of PDMS conductivity, CB powder, at lower cost was used. To optimize

    the electrophysiological properties of the electrodes, limited amount of silver

    (Ag) and silver chloride (AgCl) particles were added. The electrical characteristic

    of the electrodes and their stretchability was studied.

    Since fabrication and characterization did not require clean room enviroment,

    the developed method was less costly and less time consuming. Samples were

    made of six dierent ller concentrations in three sets, which in total were 18

    samples, in order to obtain better statistics. Resistance of all samples was measured

    and resistivity values were calculated. Tensile test were performed on all

    samples. The result showed that all samples had elongation of over 50 %, which

    is feasible for stretchable, epidermal patches. Samples with ller concentration

    of 10 wt% CB + 5 wt% Ag/AgCl and 10 wt% CB + 8 wt% Ag/AgCl showed

    resistivity of Wcm range. The electrodes were conductive, soft, stretchable and

    biocompatible. They fulll the requirements of epidermal patches for health

    monitoring.

  • 121.
    Enlund, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Johansson, Linda
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Katardjiev, Ilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Johansson, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Yantchev, Ventsislav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Acoustic manipulation of sub-micrometer particles by interface waves in microfluidic channelsArtikel i tidskrift (Refereegranskat)
  • 122.
    Eriksson, Mimmi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Corrosion and microfluidics in hot water microsystems2013Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis addresses some important issues when designing microfluidic systems for hot pressurized water. The properties and behavior of water at elevated temperatures and in micro scale is briefly reviewed, and opportunities and possible problems of using hot pressurized water in microfluidic devices are brought up. Experimental work was focused on corrosion resistance for commonly used microsystem materials in hot pressurized water, and the microfluidic behavior for hot pressurized water.

    An experiment system was successfully designed, assembled and used for corrosion resistance experiments in hot pressurized water. Corrosion resistance tests were performed for some common materials used in microfluidic and microsystems (silicon, stainless steel grade 304, silicon carbide, aluminum nitride, aluminum oxide, soda-lime glass and borosilicate glass) in deionized water and in low concentration HCl (0.1 mM) at two different temperatures (180oC and 270oC). All of the tested materials, except soda-lime glass, showed a good overall performance in the low temperature range. In the high temperature range, all materials showed signs of corrosion to some extent. Severe damages and high corrosion rates were observed for silicon and the two glasses, and stainless steel 304 showed signs of pitting corrosion.

    A microfluidic study identified some major issues needed to be overcome to make future microfluidic studies with hot pressurized water possible. Important observations included the importance of a short traveling distance for a hot micro flow to avoid rapid cooling, and to choose a suitable dye to avoid particles clogging thin capillaries and micro channels.

  • 123. Espanol, Montse
    et al.
    Mestres, Gemma
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Luxbacher, Thomas
    Ginebra, Maria-Pau
    The Role of Porosity on the Z-Potential of Calcium Phosphate Cements2014Konferensbidrag (Refereegranskat)
  • 124. Espanol, Montserrat
    et al.
    Mestres, Gemma
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Luxbacher, Thomas
    Dory, Jean-Baptiste
    Ginebra, Maria-Pau
    Impact of Porosity and Electrolyte Composition on the Surface Charge of Hydroxyapatite Biomaterials2016Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 1, s. 908-917Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The success or failure of a material when implanted in the body is greatly determined by the surface properties of the material and the host tissue reactions. The very first event that takes place after implantation is the interaction of soluble ions, molecules and proteins from the biological environment with the material surface leading to the formation of an adsorbed protein layer that will later influence cell attachment. In this context, the particular topography and surface charge of a material become critical as they influence the nature of the proteins that will adsorb. However, very limited information is available on the surface charge of porous substrates. Only until very recently was the determination of the zeta potential on porous membranes accurately determined. The goal of this work was to implement the previous findings for the determination of the zeta potential of a series of porous hydroxyapatite (HA) substrates and to assess how porosity affects the measurements. In addition, studies using various electrolytes were also performed to prove how the specific affinity of certain ions for HA can further impact surface charge. The results showed that all materials exhibited very similar external surface charge (approximately −23 mV), consistent with their almost identical topographies. However, the presence of interconnected pores underneath the sample surface resulted in an additional internal zeta potential that varied with the porosity content. Measurements with different electrolytes confirmed the selectivity of divalent ions for HA underlying the importance of testing biomaterials using relevant electrolytes.

  • 125. Evander, Mikael
    et al.
    Johansson, Linda
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Lilliehorn, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Piskur, Jure
    Lindvall, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Johansson, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Almqvist, Monica
    Laurell, Thomas
    Nilsson, Johan
    Noninvasive acoustic cell trapping in a microfluidic perfusion system for online bioassays2007Ingår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 79, nr 7, s. 2984-2991Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Techniques for manipulating, separating, and trapping particles and cells are highly desired in today's bioanalytical and biomedical field. The microfluidic chip-based acoustic noncontact trapping method earlier developed within the group now provides a flexible platform for performing cell- and particle-based assays in continuous flow microsystems. An acoustic standing wave is generated in etched glass channels (600x61 microm2) by miniature ultrasonic transducers (550x550x200 microm3). Particles or cells passing the transducer will be retained and levitated in the center of the channel without any contact with the channel walls. The maximum trapping force was calculated to be 430+/-135 pN by measuring the drag force exerted on a single particle levitated in the standing wave. The temperature increase in the channel was characterized by fluorescence measurements using rhodamine B, and levels of moderate temperature increase were noted. Neural stem cells were acoustically trapped and shown to be viable after 15 min. Further evidence of the mild cell handling conditions was demonstrated as yeast cells were successfully cultured for 6 h in the acoustic trap while being perfused by the cell medium at a flowrate of 1 microL/min. The acoustic microchip method facilitates trapping of single cells as well as larger cell clusters. The noncontact mode of cell handling is especially important when studies on nonadherent cells are performed, e.g., stem cells, yeast cells, or blood cells, as mechanical stress and surface interaction are minimized. The demonstrated acoustic trapping of cells and particles enables cell- or particle-based bioassays to be performed in a continuous flow format.

  • 126.
    Fornell, Anna
    et al.
    Department of Biomedical Engineering, Lund University, Sweden.
    Cushing, Kevin
    Department of Biomedical Engineering, Lund University, Lund, Sweden.
    Nilsson, Johan
    Department of Biomedical Engineering, Lund University, Lund, Sweden.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Intra-droplet acoustic separation of two particle species in a droplet microfluidic system2017Konferensbidrag (Refereegranskat)
  • 127.
    Fornell, Anna
    et al.
    Lund University.
    Garofalo, Fabio
    Lund University.
    Nilsson, Johan
    Lund University.
    Bruus, Henrik
    Technical University of Denmark.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab. Lund University.
    Intra-droplet acoustic particle focusing: simulations and experimental observations2018Ingår i: Microfluidics and Nanofluidics, ISSN 1613-4982, E-ISSN 1613-4990, Vol. 22, nr 75Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this paper is to study resonance conditions for acoustic particle focusing inside droplets in two-phase microfluidic systems. A bulk acoustic wave microfluidic chip was designed and fabricated for focusing microparticles inside aqueous droplets (plugs) surrounded by a continuous oil phase in a 380-μm-wide channel. The quality of the acoustic particle focusing was investigated by considering the influence of the acoustic properties of the continuous phase in relation to the dispersed phase. To simulate the system and study the acoustic radiation force on the particles inside droplets, a simplified 3D model was used. The resonance conditions and focusing quality were studied for two different cases: (1) the dispersed and continuous phases were acoustically mismatched (water droplets in fluorinated oil) and (2) the dispersed and continuous phases were acoustically matched (water droplets in olive oil). Experimentally, we observed poor acoustic particle focusing inside droplets surrounded by fluorinated oil while good focusing was observed in droplets surrounded by olive oil. The experimental results are supported qualitatively by our simulations. These show that the acoustic properties (density and compressibility) of the dispersed and continuous phases must be matched to generate a strong and homogeneous acoustic field inside the droplet that is suitable for high-quality intra-droplet acoustic particle focusing.

  • 128.
    Fornell, Anna
    et al.
    Lund University.
    Garofalo, Fabio
    Lund University.
    Nilsson, Johan
    Lund University.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab. Lund University.
    Acoustophoretic particle manipulation in droplet microfluidics at higher resonance modes2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we investigate focusing of microparticles in the presence of multiple pressure nodes inside aqueous droplets by using bulk acoustic waves. The microfluidic chip s for droplet generation and particle encapsulation (within the droplets) were fabricated using anisotropic wet - etching of a silicon wafer. Subsequently, piezoelectric transducers featuring different thicknesses were glued on the chips to build the final devices. The transducer thicknesses were chosen as to match the acoustic resonances of the embedded micro channel at the fundamental frequency, the first and the second harmonics. The actuation of the devices at the first three resonance modes enabled the positioning of the microparticles in one, two or three bands, in accordance with the presence of pressure nodes within the droplet contained in the microchannel. This acoustic particle manipulation technique opens up for new possibilities to perform biological assays using droplet microfluidic platforms.

  • 129.
    Fornell, Anna
    et al.
    Lund University.
    Garofalo, Fabio
    Lund University.
    Nilsson, Johan
    Lund University.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab. Lund University.
    Experimental investigation of resonance conditions for particle focusing in droplet acoustofluidics2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    We have experimentally studied the conditions for acoustic particle focusing inside aqueous droplets in two-phase-systems, and confirmed our findings by theoretical analysis. The results show that the acoustic properties of the two fluids have to be matched to achieve strong acoustic resonance and focusing in the system.

  • 130. Fornell, Anna
    et al.
    Joensson, Haakan
    Antfolk, Maria
    Nilsson, Johan
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Focusing microparticles inside droplets using acoustics2015Konferensbidrag (Refereegranskat)
  • 131.
    Fornell, Anna
    et al.
    Lund University.
    Joensson, Haakan
    Royal Institute of Technology (KTH).
    Nilsson, Johan
    Lund University.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Acoustic focusing of microparticles in two-phase systems: Towards cell enrichment or medium exchange in droplets2015Ingår i: 19th International Conference on Miniaturised Systems for Chemistry and Life Sciences (µTAS 2015), Gyeongju, Korea, October 25-29 2015, 2015Konferensbidrag (Refereegranskat)
  • 132.
    Fornell, Anna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Johannesson, Carl
    Lund University.
    Searle, Sean
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab. National University of Singapore.
    Happstadius, Axel
    Lund University.
    Nilsson, Johan
    Lund University.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Acoustic trapping: a non-contact method to handle cell-laden hydrogel droplets in a microchannel2019Konferensbidrag (Övrigt vetenskapligt)
  • 133.
    Fornell, Anna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Johannesson, Carl
    Lund University, Lund, Sweden.
    Searle, Sean
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab. National University of Singapore, Singapore.
    Happstadius, Axel
    Lund University, Lund, Sweden.
    Nilsson, Johan
    Lund University, Lund, Sweden.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Trapping of cell-laden hyaluronic acid-acrylamide hydrogel droplets using bulk acoustic waves2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper an acoustofluidic system to trap hydrogel droplets is shown. The presented trapping method is label-free, biocompatible and operated in non-contact mode. The results show that the droplets can be trapped at flow rates up to 76 µL/min which corresponds to an average flow speed of 3.2 mm/s. Moreover, it is shown that the droplets can be trapped for several hours, thus allowing for studies of the encapsulated cells over time. An application of the system is shown by performing on-chip cell nuclei staining. 

  • 134.
    Fornell, Anna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Johannesson, Carl
    Lund University.
    Searle, Sean S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab. Natl Univ Singapore, Dept Biomed Engn, Fac Engn,.
    Happstadius, Axel
    Lund University.
    Nilsson, Johan
    Lund University.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    An acoustofluidic platform for non-contact trapping of cell-laden hydrogel droplets compatible with optical microscopy2019Ingår i: Biomicrofluidics, ISSN 1932-1058, E-ISSN 1932-1058, Vol. 13, artikel-id 044101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Production of cell-laden hydrogel droplets as miniaturized niches for 3D cell culture provides a new route for cell-based assays. Such production can be enabled by droplet microfluidics and here we present a droplet trapping system based on bulk acoustic waves for handling hydrogel droplets in a continuous flow format. The droplet trapping system consists of a glass capillary equipped with a small piezoelectric transducer. By applying ultrasound (4 MHz), a localized acoustic standing wave field is generated in the capillary, trapping the droplets in a well-defined cluster above the transducer area. The results show that the droplet cluster can be retained at flow rates of up to 76 mu l/min, corresponding to an average flow speed of 3.2 mm/s. The system allows for important operations such as continuous perfusion and/or addition of chemical reagents to the encapsulated cells with in situ optical access. This feature is demonstrated by performing on-chip staining of the cell nuclei. The key advantages of this trapping method are that it is label-free and gentle and thus well-suited for biological applications. Moreover, the droplets can easily be released on-demand, which facilitates downstream analysis. It is envisioned that the presented droplet trapping system will be a valuable tool for a wide range of multistep assays as well as long-term monitoring of cells encapsulated in gel-based droplets.

  • 135.
    Fornell, Anna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Liu, Zhenhua
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Improved acoustic particle enrichment in droplets by optimising the droplet split design2019Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Droplet microfluidics has emerged as a valuable platform for miniaturisation of biological experiments on-chip. In droplet microfluidic chips monodisperse droplets containing cells or other bioparticles can be generated at high throughput, and each droplet can be used as an isolated reaction chamber for individual measurements. A general trend in droplet microfluidics is reducing the size of the droplets, but the challenge is maintaining the particles in the droplets after splitting. We have previously reported on an acoustofluidic chip where bulk acoustic waves were used to control particle positioning in a trident-shaped droplet split. However, the reported particle enrichment was modest (3-fold), and the aim of this study is to increase the particle enrichment by optimising the droplet split design. With our new optimised droplet split we show up to 16.7-fold particle enrichment with high particle recovery.

  • 136. Fornell, Anna
    et al.
    Nilsson, Johan
    Jonsson, Linus
    Periyannan Rajeswari, Prem
    Joensson, Haakan
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Controlled lateral positioning of microparticles inside droplets using acoustophoresis2015Ingår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 87, nr 20, s. 10521-10526Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we utilize bulk acoustic waves to control the position of microparticles inside droplets in two-phase microfluidic systems and demonstrate a method to enrich the microparticles. In droplet microfluidics, different unit operations are combined and integrated on-chip to miniaturize complex biochemical assays. We present a droplet unit operation capable of controlling the position of microparticles during a trident shaped droplet split. An acoustic standing wave field is generated in the microchannel, and the acoustic forces direct the encapsulated microparticles to the center of the droplets. The method is generic, requires no labeling of the microparticles, and is operated in a noncontact fashion. It was possible to achieve 2+-fold enrichment of polystyrene beads (5 μm in diameter) in the center daughter droplet with an average recovery of 89% of the beads. Red blood cells were also successfully manipulated inside droplets. These results show the possibility to use acoustophoresis in two-phase systems to enrich microparticles and open up the possibility for new droplet-based assays that are not performed today.

  • 137.
    Fornell, Anna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Nilsson, Johan
    Jonsson, Linus
    Periyannan Rajeswari, Prem
    Joensson, Haakan
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Particle enrichment in droplet acoustofluidics2016Konferensbidrag (Refereegranskat)
  • 138.
    Fornell, Anna
    et al.
    Lund University.
    Nilsson, Johan
    Lund University.
    Jonsson, Linus
    Lund University.
    Periyannan Rajeswari, Prem
    KTH, Science for Life Laboratory.
    Joensson, Haakan
    KTH, Science for Life Laboratory.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab. Lund University.
    Particle enrichment in two-phase microfluidic systems using acoustophoresis2016Konferensbidrag (Refereegranskat)
  • 139.
    Fornell, Anna
    et al.
    Lund University.
    Ohlin, Mathias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Garofalo, Fabio
    Department Biomedical Engineering, Lund University.
    Nilsson, Johan
    Department Biomedical Engineering, Lund University.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab. Department Biomedical Engineering, Lund University.
    An intra-droplet particle switch for droplet microfluidics using bulk acoustic waves2017Ingår i: Biomicrofluidics, ISSN 1932-1058, E-ISSN 1932-1058, Vol. 11, artikel-id 031101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To transfer cell- and bead-assays into droplet-based platforms typically requires the use of complex microfluidic circuits, which calls for methods to switch the direction of the encapsulated particles. We present a microfluidic chip where the combination of acoustic manipulation at two different harmonics and a trident-shaped droplet-splitter enables direction-switching of microbeads and yeast cells in droplet microfluidic circuits. At the first harmonic, the encapsulated particles exit the splitter in the center daughter droplets, while at the second harmonic, the particles exit in the side daughter droplets. This method holds promises for droplet-based assays where particle-positioning needs to be selectively controlled.

  • 140.
    Fornell, Anna
    et al.
    Department of Biomedical Engineering, Lund University, Sweden.
    Ohlin, Mathias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Nilsson, Johan
    Department Biomedical Engineering, Lund University.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    A droplet unit operator for controlled particle switching and enrichment2017Konferensbidrag (Refereegranskat)
  • 141.
    Fornell, Anna
    et al.
    Department of Biomedical Engineering, Lund University, Sweden.
    Ohlin, Mathias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Nilsson, Johan
    Department of Biomedical Engineering, Lund University, Sweden.
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    An optimized droplet split designed for acoustic intra-droplet particle enrichment2017Konferensbidrag (Refereegranskat)
  • 142.
    Fornell, Anna
    et al.
    Lund Univ, Dept Biomed Engn, Lund, Sweden..
    Cushing, Kevin
    Lund Univ, Dept Biomed Engn, Lund, Sweden..
    Nilsson, Johan
    Lund Univ, Dept Biomed Engn, Lund, Sweden..
    Tenje, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Science for Life Laboratory, SciLifeLab. Lund Univ, Dept Biomed Engn, Lund, Sweden.
    Binary particle separation in droplet microfluidics using acoustophoresis2018Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 112, nr 6, artikel-id 063701Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We show a method for separation of two particle species with different acoustic contrasts originally encapsulated in the same droplet in a continuous two-phase system. This was realized by using bulk acoustic standing waves in a 380 mu m wide silicon-glass microfluidic channel. Polystyrene particles (positive acoustic contrast particles) and in-house synthesized polydimethylsiloxane (PDMS) particles (negative acoustic contrast particles) were encapsulated inside water-in-oil droplets either individually or in a mixture. At acoustic actuation of the system at the fundamental resonance frequency, the polystyrene particles were moved to the center of the droplet (pressure node), while the PDMS particles were moved to the sides of the droplet (pressure anti-nodes). The acoustic particle manipulation step was combined in series with a trifurcation droplet splitter, and as the original droplet passed through the splitter and was divided into three daughter droplets, the polystyrene particles were directed into the center daughter droplet, while the PDMS particles were directed into the two side daughter droplets. The presented method expands the droplet microfluidics tool-box and offers new possibilities to perform binary particle separation in droplet microfluidic systems.

  • 143.
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Diamond Microfabrication for Applications in Optics and Chemical Sensing2013Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Diamond is a material with many exceptional properties. In this thesis methods for fabrication of microstructures as well as several applications of such structures in optics, microfluidics and electrochemistry are presented.

    A method for etching deep and highly precise gratings is described. This method was used to fabricate circularly symmetric half wave plates for use in vector vortex coronagraphs. Such coronagraphs are a very promising approach to the direct imaging of extrasolar planets.

    By varying the lateral etch rate of the aluminum mask during diamond etching in an inductively coupled plasma, the sidewall angle of the etched structures could be controlled. This method was used to make smooth sloped sides on a waveguide for coupling light into it. Antireflective structures that drastically reduced the surface reflection in a wavelength band between 10 and 50 µm were also fabricated.

    An array of boron doped diamond microelectrodes for electrochemical measurements in a microchannel was fabricated and tested, showing very good stability and reusability. Several hundred hours of use did not adversely affect their performance and no damage to them could be detected by atomic force microscopy or scanning electron microscopy.

    Superhydrophobic surfaces in diamond were demonstrated, using both hydrogen and fluorine termination. Hydrogen termination on a flat surface gives contact angles below 90°. To achieve a superhydrophobic surface with this low intrinsic hydrophobicity, structures looking like microscopic nail heads were fabricated. The effect of water pressure on immersed superhydrophobic surfaces was also studied and it was found that the collapse of the superhydrophobic state due to pressure was sometimes reversible as the pressure was lowered.

    Finally, a method was tested for functionalizing diamond surfaces using block copolymers of polyethylene oxide and polypropylene oxide to both passivate the surface and to attach synthetic binder molecules. This method was found to give very high signal to noise ratios when detecting C-reactive protein.

    Delarbeten
    1. High aspect ratio optical gratings in diamond
    Öppna denna publikation i ny flik eller fönster >>High aspect ratio optical gratings in diamond
    2013 (Engelska)Ingår i: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 34, s. 19-24Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In this paper we describe a process for fabricating high aspect ratio gratings in single- or polycrystalline diamond with the high precision required by micro-optics. Nanoimprint lithography with a soft stamp and several layers of hard masks allowed for rapid and accurate replication of patterns written by e-beam or laser into thick Al masks on diamond substrates as large as 2 cm in diameter. Vertical sidewalls in the mask were crucial for avoiding microvilli formation during diamond plasma etching and were achieved by etching and oxidizing the Al mask in cycles. Circularly symmetric half-wave plates for wavelength bands around 4 and 11 mu m were fabricated with deep circular gratings on one side and antireflective gratings on the other.

    Nyckelord
    Reactive ion etching, synthetic diamond, plasma etching, grating, optics, interface structure
    Nationell ämneskategori
    Bearbetnings-, yt- och fogningsteknik Astronomi, astrofysik och kosmologi
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik
    Identifikatorer
    urn:nbn:se:uu:diva-192561 (URN)10.1016/j.diamond.2013.01.009 (DOI)000317795400004 ()
    Tillgänglig från: 2013-01-22 Skapad: 2013-01-22 Senast uppdaterad: 2017-12-06Bibliografiskt granskad
    2. Design, manufacturing, and performance analysis of mid-infrared achromatic half-wave plates with diamond subwavelength gratings
    Öppna denna publikation i ny flik eller fönster >>Design, manufacturing, and performance analysis of mid-infrared achromatic half-wave plates with diamond subwavelength gratings
    Visa övriga...
    2012 (Engelska)Ingår i: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 51, nr 24, s. 5897-5902Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In this paper, we present a solution for creating robust monolithic achromatic half-wave plates (HWPs) for the infrared, based on the form birefringence of subwavelength gratings (SWGs) made out of diamond. We use the rigorous coupled wave analysis to design the gratings. Our analysis shows that diamond, besides its outstanding physical and mechanical properties, is a suitable substrate to manufacture mid-infrared HWPs, thanks to its high refractive index, which allows etching SWGs with lower aspect ratio. Based on our optimized design, we manufactured a diamond HWP for the 11-13.2 mu m region, with an estimated mean retardance similar to 3.143 +/- 0.061 rad ( 180.08 +/- 3.51 degrees). In addition, an antireflective grating was etched on the backside of the wave plate, allowing a total transmittance between 89% and 95% over the band.

    Nationell ämneskategori
    Fysik Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik
    Identifikatorer
    urn:nbn:se:uu:diva-182532 (URN)10.1364/AO.51.005897 (DOI)000308076600020 ()
    Tillgänglig från: 2012-10-12 Skapad: 2012-10-11 Senast uppdaterad: 2017-12-07Bibliografiskt granskad
    3. Laboratory demonstration of a mid-infrared AGPM vector vortex coronagraph
    Öppna denna publikation i ny flik eller fönster >>Laboratory demonstration of a mid-infrared AGPM vector vortex coronagraph
    Visa övriga...
    2013 (Engelska)Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 553, s. A98-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Context. Coronagraphy is a powerful technique to achieve high contrast imaging, hence to image faint companions around bright targets. Various concepts have been used in the visible and near-infrared regimes, while coronagraphic applications in the mid-infrared nowadays remain largely unexplored. Vector vortex phase masks based on concentric subwavelength gratings show great promise for such applications.

    Aims. We aim at producing and validating the first high-performance broadband focal plane phase mask coronagraphs for applications in the mid-infrared regime, and in particular the L band with a fractional bandwidth of  ~16% (3.5–4.1 μm).

    Methods. Based on rigorous coupled wave analysis, we designed an annular groove phase mask (AGPM) producing a vortex effect in the L band, and etched it onto a series of diamond substrates. The grating parameters were measured by means of scanning electron microscopy. The resulting components were then tested on a mid-infrared coronagraphic test bench.

    Results. A broadband raw null depth of 2 × 10-3 was obtained for our best L-band AGPM after only a few iterations between design and manufacturing. This corresponds to a raw contrast of about 6 × 10-5 (10.5 mag) at 2λ/D. This result is fully in line with our projections based on rigorous coupled wave analysis modelling, using the measured grating parameters. The sensitivity to tilt and focus has also been evaluated.

    Conclusions. After years of technological developments, mid-infrared vector vortex coronagraphs have finally become a reality and live up to our expectations. Based on their measured performance, our L-band AGPMs are now ready to open a new parameter space in exoplanet imaging at major ground-based observatories.

    Nyckelord
    coronagraph diamond
    Nationell ämneskategori
    Astronomi, astrofysik och kosmologi Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik
    Identifikatorer
    urn:nbn:se:uu:diva-192563 (URN)10.1051/0004-6361/201321126 (DOI)000319858700098 ()
    Tillgänglig från: 2013-01-22 Skapad: 2013-01-22 Senast uppdaterad: 2017-12-06Bibliografiskt granskad
    4. Inclined surfaces in diamond: broadband antireflective structures and coupling light through waveguides
    Öppna denna publikation i ny flik eller fönster >>Inclined surfaces in diamond: broadband antireflective structures and coupling light through waveguides
    2013 (Engelska)Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, nr 3, s. 2693-2700Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

     Control of the sidewall angle of diamond microstructures was achieved by varying the gas mixture, bias power and mask shape during inductively coupled plasma etching. Different etch mechanisms were responsible for the angle of the lower and upper part of the sidewall formed during diamond etching. These angles could to some extent be controlled separately. The developed etch process was used to fabricate wideband antireflective structures with an average transmission of 96.4% for wavelengths between 10 and 50 mu m. Smooth facetted edges for coupling light through waveguides from above were also demonstrated. 

    Nyckelord
    diamond, etching, waveguide, antireflection
    Nationell ämneskategori
    Bearbetnings-, yt- och fogningsteknik Annan fysik
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik
    Identifikatorer
    urn:nbn:se:uu:diva-192566 (URN)10.1364/OE.21.002693 (DOI)000315991400015 ()
    Tillgänglig från: 2013-01-22 Skapad: 2013-01-22 Senast uppdaterad: 2017-12-06
    5. Designed protein binders in combination with nanocrystalline diamond for use in high-sensitivity biosensors
    Öppna denna publikation i ny flik eller fönster >>Designed protein binders in combination with nanocrystalline diamond for use in high-sensitivity biosensors
    Visa övriga...
    2012 (Engelska)Ingår i: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 404, nr 6-7, s. 1643-1651Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A platform for diagnostic applications showing signal-to-noise ratios that by far surpass those of traditional bioanalytical test formats has been developed. It combines the properties of modified nanocrystalline diamond (NCD) surfaces and those of polyethylene oxide and polypropylene oxide based block copolymers for surface passivation and binder conjugation with a new class of synthetic binders for proteins. The NCD surfaces were fluorine-, hydrogen-, or oxygen-terminated prior to further biofunctionalization and the surface composition was characterized by X-ray photoelectron spectroscopy. In a proof of principle demonstration targeting the C-reactive protein, an ELISA carried out using an F-terminated diamond surface showed a signal-to-noise ratio of 3,900 which compares well to the signal-to-noise of 89 obtained in an antibody-based ELISA on a polystyrene microtiter plate, a standard test format used in most life science laboratories today. The increase in signal-to-noise ratio is to a large extent the result of extremely efficient passivation of the diamond surface. The results suggest that significant improvements can be obtained in standardized test formats using new materials in combination with new types of chemical coatings and receptor molecules.

    Nyckelord
    Protein binders, Nanocrystalline diamond, CRP, Biosensor, Surface characterization
    Nationell ämneskategori
    Naturvetenskap Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik
    Identifikatorer
    urn:nbn:se:uu:diva-184455 (URN)10.1007/s00216-012-6245-7 (DOI)000309348400004 ()
    Tillgänglig från: 2012-11-09 Skapad: 2012-11-07 Senast uppdaterad: 2017-12-07Bibliografiskt granskad
    6. From Hydrophilic to Superhydrophobic: Fabrication of Micrometer-Sized Nail-Head-Shaped Pillars in Diamond
    Öppna denna publikation i ny flik eller fönster >>From Hydrophilic to Superhydrophobic: Fabrication of Micrometer-Sized Nail-Head-Shaped Pillars in Diamond
    2010 (Engelska)Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, nr 2, s. 889-893Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The hydrophobicity of microtextured diamond surfaces was investigated. Pillarlike structures were fabricated in both nanocrystalline diamond and microcrystalline diamond. By changing the surface termination of the textured diamond surface, we could switch between superhydrophobic surfaces and hydrophilic surfaces. Examined terminations were hydrogen, fluorine, and oxygen. To evaluate the wetting properties, advancing and receding contact angles were measured. By designing pillars with a wide diamond top on a narrower silicon stem, superhydrophobicity was achieved even when the advancing contact angle on the unstructured diamond surface was below 70°. The possibility to manipulate the hydrophobicity and the Fresnel reflection simultaneously at an infrared wavelength is also demonstrated.

    Nyckelord
    superhydrophobic diamond nanocrystalline polycrystalline cassie wenzel
    Nationell ämneskategori
    Den kondenserade materiens fysik Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-135623 (URN)10.1021/la902361c (DOI)000273403400038 ()
    Anmärkning

    PMID: 19775135

    Tillgänglig från: 2010-12-07 Skapad: 2010-12-07 Senast uppdaterad: 2017-12-11
    7. Cassie-Wenzel and Wenzel-Cassie transitions on immersed superhydrophobic surfaces under hydrostatic pressure
    Öppna denna publikation i ny flik eller fönster >>Cassie-Wenzel and Wenzel-Cassie transitions on immersed superhydrophobic surfaces under hydrostatic pressure
    2011 (Engelska)Ingår i: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 7, nr 1, s. 104-109Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    For incorporating superhydrophobic surfaces in microfluidic systems, it is important to understand the ability of the superhydrophobic state to withstand hydraulic pressure. In this paper we describe experiments to probe the collapse transition on superhydrophobic surfaces completely covered by water, where the air film formed on the surface is closed. Polyethylene foils nanoimprinted with micrometre sized pillars in different geometries and densities are used as the model superhydrophobic surfaces. The pressure required for the transition from Cassie to Wenzel state is measured for all surfaces and also compared to analytical and numerical models. We find that the closed film of trapped air helps stabilise the Cassie state at low pillar densities and that the effect of a small change in pillar sidewall angle can drastically change the collapse behaviour. Finally, the reverse transition, from Wenzel to Cassie state, is observed on densely pillared surfaces at low water pressure.

    Nationell ämneskategori
    Fysikalisk kemi Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik
    Identifikatorer
    urn:nbn:se:uu:diva-134448 (URN)10.1039/C0SM00595A (DOI)000285360200015 ()
    Tillgänglig från: 2010-11-26 Skapad: 2010-11-26 Senast uppdaterad: 2018-05-28
    8. Fabrication of boron doped diamond microband electrodes for electrochemical detection in a microfluidic channel
    Öppna denna publikation i ny flik eller fönster >>Fabrication of boron doped diamond microband electrodes for electrochemical detection in a microfluidic channel
    Visa övriga...
    2011 (Engelska)Ingår i: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 20, nr 8, s. 1121-1124Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The manufacturing and electrochemical characterisation of an array of 20 boron doped nanocrystalline diamond (BNCD) microband electrodes for use in a poly(dimethylsiloxane) (PDMS) based microfluidic system are described. The electrodes were fabricated by plasma etching of a silicon oxide- and BNCD thin film coated silicon wafer and the resulting surface structured silicon wafer was subsequently bonded to the PDMS so that the BNCD microband electrodes were located within the PDMS microchannel. The electrochemical performance of the BNCD electrodes was studied and the electrodes were found to exhibit significantly better stability than previously employed gold microband arrays.

    Nyckelord
    Nanocrystalline, Diamond film, Electrodes, Electrochemical applications, Micro electromechanical systems, Sensors
    Nationell ämneskategori
    Teknik och teknologier Oorganisk kemi
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik; Oorganisk kemi
    Identifikatorer
    urn:nbn:se:uu:diva-160514 (URN)10.1016/j.diamond.2011.06.024 (DOI)000295300800004 ()
    Tillgänglig från: 2011-10-25 Skapad: 2011-10-25 Senast uppdaterad: 2017-12-08
  • 144.
    Forsberg, Pontus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Delacroix, Christian
    Université de Liège, Belgium.
    Mawet, Dimitri
    European Southern Observatory, Chile.
    Absil, Olivier
    Université de Liège, Belgium.
    Hanot, Charles
    Université de Liège, Belgium.
    Habraken, Serge
    Université de Liège, Belgium.
    Surdej, Jean
    Université de Liège, Belgium.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Etching High Aspect Ratio Optical Gratings in Diamond2012Konferensbidrag (Refereegranskat)
  • 145.
    Forsberg, Pontus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Delacroix, Christian
    Université de Liège, Belgium.
    Mawet, Dimitri
    European Southern Observatory, Chile.
    Absil, Olivier
    Université de Liège, Belgium.
    Hanot, Charles
    Université de Liège, Belgium.
    Habraken, Serge
    Université de Liège, Belgium.
    Surdej, Jean
    Université de Liège, Belgium.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Fabricating an annular groove phase mask in diamond2012Konferensbidrag (Refereegranskat)
  • 146.
    Forsberg, Pontus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Hamberg, Mathias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Diamond gratings for dielectric laser acceleration2019Konferensbidrag (Refereegranskat)
  • 147.
    Forsberg, Pontus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Jorge, Eleonora de Oliveira
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Nyholm, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Nikolajeff, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Fabrication of boron doped diamond microband electrodes for electrochemical detection in a microfluidic channel2011Ingår i: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 20, nr 8, s. 1121-1124Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The manufacturing and electrochemical characterisation of an array of 20 boron doped nanocrystalline diamond (BNCD) microband electrodes for use in a poly(dimethylsiloxane) (PDMS) based microfluidic system are described. The electrodes were fabricated by plasma etching of a silicon oxide- and BNCD thin film coated silicon wafer and the resulting surface structured silicon wafer was subsequently bonded to the PDMS so that the BNCD microband electrodes were located within the PDMS microchannel. The electrochemical performance of the BNCD electrodes was studied and the electrodes were found to exhibit significantly better stability than previously employed gold microband arrays.

  • 148.
    Forsberg, Pontus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    High aspect ratio optical gratings in diamond2013Ingår i: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 34, s. 19-24Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper we describe a process for fabricating high aspect ratio gratings in single- or polycrystalline diamond with the high precision required by micro-optics. Nanoimprint lithography with a soft stamp and several layers of hard masks allowed for rapid and accurate replication of patterns written by e-beam or laser into thick Al masks on diamond substrates as large as 2 cm in diameter. Vertical sidewalls in the mask were crucial for avoiding microvilli formation during diamond plasma etching and were achieved by etching and oxidizing the Al mask in cycles. Circularly symmetric half-wave plates for wavelength bands around 4 and 11 mu m were fabricated with deep circular gratings on one side and antireflective gratings on the other.

  • 149.
    Forsberg, Pontus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Inclined surfaces in diamond: broadband antireflective structures and coupling light through waveguides2013Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, nr 3, s. 2693-2700Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     Control of the sidewall angle of diamond microstructures was achieved by varying the gas mixture, bias power and mask shape during inductively coupled plasma etching. Different etch mechanisms were responsible for the angle of the lower and upper part of the sidewall formed during diamond etching. These angles could to some extent be controlled separately. The developed etch process was used to fabricate wideband antireflective structures with an average transmission of 96.4% for wavelengths between 10 and 50 mu m. Smooth facetted edges for coupling light through waveguides from above were also demonstrated. 

  • 150.
    Forsberg, Pontus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Nikolajeff, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Cassie-Wenzel and Wenzel-Cassie transitions on immersed superhydrophobic surfaces under hydrostatic pressure2011Ingår i: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 7, nr 1, s. 104-109Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For incorporating superhydrophobic surfaces in microfluidic systems, it is important to understand the ability of the superhydrophobic state to withstand hydraulic pressure. In this paper we describe experiments to probe the collapse transition on superhydrophobic surfaces completely covered by water, where the air film formed on the surface is closed. Polyethylene foils nanoimprinted with micrometre sized pillars in different geometries and densities are used as the model superhydrophobic surfaces. The pressure required for the transition from Cassie to Wenzel state is measured for all surfaces and also compared to analytical and numerical models. We find that the closed film of trapped air helps stabilise the Cassie state at low pillar densities and that the effect of a small change in pillar sidewall angle can drastically change the collapse behaviour. Finally, the reverse transition, from Wenzel to Cassie state, is observed on densely pillared surfaces at low water pressure.

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