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  • 1.
    Ahlén, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Ahlgren, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Grönroos, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Katardjiev, Ilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Presentation of the VINN Excellence Center for Wireless Sensor Networks (WISENET)2008In: Conference on Radio Science (RVK08), Växjö, 2008Conference paper (Refereed)
  • 2. Ali, M.
    et al.
    Svensk, O.
    Zhen, Z.
    Suihkonen, S.
    Törmä, P. T.
    Lipsanen, H.
    Sopanen, M.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Jensen, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Reduced photoluminescence from InGaN/GaN multiple quantum well structures following 40 MeV iodine ion irradiation2009In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 404, no 23-24, 4925-4928 p.Article in journal (Refereed)
    Abstract [en]

    The effects following ion irradiation of GaN-based devices are still limited. Here we present data on the photoluminescence (PL) emitted from InGaN/GaN multiple quantum well (MQW) structures, which have been exposed to 40 MeV lion irradiation. The PL is reduced as a function of applied ion fluence, with essentially no PL signal left above 10(11) ions/cm(2). It is observed that even the ion fluences in the 10(9) ions/cm(2) range have a pronounced effect on the photoluminescence properties of the MQW structures. This may have consequences concerning application of InGaN/GaN MQW's in radiation-rich environments, in addition to defect build-up during ion beam analysis.

  • 3.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ek, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hedman, Ludvig
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Johansson, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sehlstedt, Viktor
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Stocklassa, Jesper
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Snögren, Pär
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Pettersson, Victor
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Larsson, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Vizuete, Olivier
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thin film metal sensors in fusion bonded glass chips for high-pressure microfluidics2017In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 27, no 1, 015018Article in journal (Refereed)
    Abstract [en]

    High-pressure microfluidics offers fast analyses of thermodynamic parameters for compressed process solvents. However, microfluidic platforms handling highly compressible supercritical CO2 are difficult to control, and on-chip sensing would offer added control of the devices. Therefore, there is a need to integrate sensors into highly pressure tolerant glass chips. In this paper, thin film Pt sensors were embedded in shallow etched trenches in a glass wafer that was bonded with another glass wafer having microfluidic channels. The devices having sensors integrated into the flow channels sustained pressures up to 220 bar, typical for the operation of supercritical CO2. No leakage from the devices could be found. Integrated temperature sensors were capable of measuring local decompression cooling effects and integrated calorimetric sensors measured flow velocities over the range 0.5-13.8 mm/s. By this, a better control of high-pressure microfluidic platforms has been achieved.

    The full text will be freely available from 2017-12-14 08:00
  • 4.
    Andersson, Martin
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Fracture strength of glass chips for high-pressure microfluidics2016In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 9, 095009Article in journal (Refereed)
    Abstract [en]

    High-pressure microfluidics exposes new areas in chemistry. In this paper, the reliability of transparent borosilicate glass chips is investigated. Two designs of circular cavities are used for fracture strength tests, either 1.6 mm wide with rounded corners to the fluid inlets, or 2.0 mm wide with sharp inlet corners. Two kinds of tests are done, either short-term,e.g. pressurization to fracture at room temperature, or long-term, with fracture at constant pressurization for up to one week, in the temperature region 11–125 °C. The speed of crack fronts is measured using a high-speed camera. Results show fracture stresses in the range of 129 and 254 MPa for short-term measurements. Long-term measurements conclude the presences of a temperature and stress dependent delayed fracture. For a reliability ofone week at 11–38 °C, a pressure limit is found at the lower end of the short-term measurements, or 15% lower than the average. At 80 °C, this pressure limit is 45% lower. Crack speeds are measured to be 10−5 m s-1 during short-term fracture. These measurements are comparable with estimations based on slow crack growth and show that the growth affects the reliability of glass chips. This effect is strongly affected by high temperatures, thus lowers the operating window of high-pressure glass microfluidic devices.

  • 5.
    Andersson, Martin
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High pressure glass microfluidics for supercritical CO2 with aqueous solutions2016Conference paper (Refereed)
    Abstract [en]

    A microfluidic system is presented to investigate interactions between supercritical CO2 and H2O using high-pressure glass chips. The reliability of these chips at pressures necessary to sustain CO2 in the supercritical phase is dependent of both time and temperature. 130 bar can be kept at 38°C for more than a week. These systems can be used to investigate fluid interaction between supercritical CO2 and aqueous solutions by the addition of pH sensitive dye and high speed absorption light imagining, making it possible to demonstrate acidification is in a multiphase chip. By the addition of integrated temperature sensors, better control of the states of the fluids inside the chips can be achieved.

  • 6.
    Andersson, Martin
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High-Speed Imaging Of The ph Drop In Aqueous solutions In Contact With Supercritical Co2 Segments2016Conference paper (Other academic)
    Abstract [en]

    A high-speed imaging system based on light absorption of bromophenol blue (BPB) pH sensitivedye in a glass high-pressure microchip is used to study the instantaneous dynamics of a pH drop in anaqueous phase in contact with segments of subcritical (liquid) and supercritical CO2. The dynamics ofthe pH-drop has been studied and visualized, demonstrating acidification rates of up to 3.5 pH/s.

  • 7.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    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 Glass Devices For CO2 And H2O2016Conference paper (Other academic)
    Abstract [en]

    A microfluidic system is presented to investigate interactions between supercritical CO2 and H2O using high-pressure glass chips. The reliability of these chips at pressures necessary to sustain CO2 in the supercritical phase is dependent of both time and temperature. 130 bar can be kept at 38°C for more than a week. These systems can be used to create parallel flow streams used to investigate reaction dynamics by the addition of pH sensitive dyes. 

  • 8.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Knaust, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    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.
    Bodén, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Integrated high-pressure fluid manipulation in microfluidic systems2014Conference paper (Other academic)
  • 9.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Stocklassa, Jesper
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    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.
    Control Systems For Gas-Expanded Liquids In Microreactors2017Conference paper (Other academic)
  • 10. Bjerketorp, J.
    et al.
    Ng Tze Chiang, A.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Rosenquist, M.
    Liu, Wen-Tso
    Jansson, J. K.
    Rapid lab-on-a-chip profiling of human gut bacteria2008In: Journal of Microbiological Methods, ISSN 0167-7012, E-ISSN 1872-8359, Vol. 72, no 1, 82-90 p.Article in journal (Refereed)
    Abstract [en]

    The human gut microbiota has a substantial impact on human health. Different factors such as disease, diet and drug use can have significant impacts on the gut microbiota. Therefore, it is of interest to have simple, rapid methods for analysis of the composition of the gut microbiota for clinical diagnostic purposes. Since only a minor fraction of the gastrointestinal bacterial community is presently possible to cultivate, molecular approaches are currently the best suited to investigate its composition. However, most of these molecular approaches require technical expertise and expensive equipment to run and they are not routinely available. Ideally, the analyses should be point-of-care options that can be run on a chip. In this study, an existing lab-on-chip (LOC) system for sizing/quantifying DNA was combined with length heterogeneity PCR (LH-PCR), a PCR-based profiling method targeting bacterial 16S rRNA gene sequences, to develop a fast, straightforward, reproducible, and economical method for profiling bacterial communities. The LOC LH-PCR method was first evaluated using a standardized gut cocktail containing genomic DNA from eight different bacterial species representing different genera of relevance for human health. The method was also tested on DNA that was directly extracted from human faecal samples and it was consistently capable of detecting alterations in the bacterial samples before and after antibiotic treatment. Although the resolution of the method needs improvement, this study represents the first step towards development of a diagnostic LOC for profiling gut bacterial communities.

  • 11.
    Bjorkman, H
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. MATERIALS SCIENCE.
    Rangsten, Pelle
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Hjort, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. Materialvetenskap.
    Diamond microstructures for optical micro electromechanical systems1999In: SENSORS AND ACTUATORS A-PHYSICAL, ISSN 0924-4247, Vol. 78, no 1, 41-47 p.Article in journal (Refereed)
    Abstract [en]

    We have used hot filament chemical vapour deposition (HFCVD) to fabricate diamond microstructure components for optical micro electromechanical systems (MEMS). In order to demonstrate the wide application range for diamond technology we have made componen

  • 12.
    Bjorkman, H
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. MATERIALS SCIENCE.
    Rangsten, Pelle
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Hollman, Patrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. Materialvetenskap.
    Hjort, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. Materialvetenskap.
    Diamond replicas from microstructured silicon masters1999In: SENSORS AND ACTUATORS A-PHYSICAL, ISSN 0924-4247, Vol. 73, no 1-2, 24-29 p.Article in journal (Refereed)
    Abstract [en]

    We are developing a microstructure technology for thick film diamond replicas, using deposition by hot filament chemical vapour deposition (CVD) on microstructured silicon. This technology is primarily intended to make micromechanical structures for micro

  • 13.
    Boden, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Simu, U.
    Margell, J.
    Lehto, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Materialvetenskap.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Metallic high-pressure microfluidicpump with active valves2007Conference paper (Refereed)
  • 14.
    Bodén, Roger
    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.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Simu, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A metallic micropump for high-pressure microfluidics2008In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 18, no 11, 115009- p.Article in journal (Refereed)
    Abstract [en]

    This paper presents one of the strongest mechanical sub-cm(3) sized micropumps for microfluidics. It consists of two active valves and one pumping chamber, each operated by a paraffin actuator that is driven by a low-voltage square pulse waveform. The pump is fabricated in a simple process using parylene-coated stainless steel stencils, paraffin and copper clad polyimide. When driving the pump at 0.07 Hz and 2.0 V (0.8 W) per actuator, it pumped water without leakage at a flow rate of 0.75 mu L min(-1) up to above 50 bar (5 MPa) back-pressure. The frequency dependence was evaluated and a maximum flow rate of 1 mu L min(-1) at 0.21 Hz and 1.8 V was observed. A thermomechanical FEM analysis, which was in good agreement with experiments at low frequencies, predicts the behaviour at higher frequencies.

  • 15.
    Bodén, Roger
    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.
    Simu, Urban
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Metallic high-pressure microfluidic pump2008In: MSW08, 2008, 29- p.Conference paper (Refereed)
  • 16.
    Bodén, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Lehto, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Margell, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    On-chip liquid storage and dispensing for lab-on-a-chip applications2008In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 18, no 7, 075036- p.Article in journal (Refereed)
    Abstract [en]

    This work presents novel components for on-chip storage and dispensing inside a lab-on-a-chip (LOC) for applications in immunoassay point-of-care testing (POCT), where incubation and washing steps are essential. It involves easy-to-use on-chip solutions for the sequential thermo-hydraulic actuation of liquids. The novel concept of combining the use of a rubber plug, both as a non-return valve cap and as a liquid injection interface of a sealed reservoir, allows simple filling of a sterilized cavity, as well as the storage and dispensing of reagent and washing buffer liquids. Segmenting the flow with air spacers enables effective rinsing and the use of small volumes of on-chip stored liquids. The chip uses low-resistance resistors as heaters in the paraffin actuator, providing the low-voltage actuation that is preferred for handheld battery driven instruments.

  • 17.
    Bodén, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Lehto, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Margell, Joakim
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Towards a self-contained Lab on a Chip concept with sequential drive for point-of-care testingIn: Lab-on-a-chipArticle in journal (Other academic)
  • 18.
    Bodén, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Lehto, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Simu, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    A polymeric paraffin actuated high-pressure micropump2006In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 127, no 1, 88-93 p.Article in journal (Refereed)
  • 19.
    Bodén, Roger
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Lehto, Marcus
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Thornell, Greger
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Hjort, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Schweitz, Jan-Åke
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    A Polymeric Paraffin Micropump with Active Valves for High-Pressure Microfluidics2005In: The 13th International Conference on Solid-State Sensors, Actuators and Microsystems, Seoul, Korea, 2005Conference paper (Refereed)
  • 20.
    Bodén, Roger
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Lehto, Marcus
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Thornell, Greger
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Hjort, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Schweitz, Jan-Åke
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    A polymeric paraffin actuated high-pressure micropump2005In: SenArticle in journal (Refereed)
  • 21.
    Bodén, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    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.
    Microdispenser with continuous flow and selectable target volume for microfluidic high-pressure applications2014In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 23, no 2, 452-458 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a reusable microdispenser intended for continuous flow dispensing of variable and controlled volumes of liquid against high back-pressures. The microdispenser consists of two active valves and a dispenser chamber, all actuated by the volume change associated with the solid-to-liquid phase transition of paraffin wax. It is fabricated using stainless steel sheets, a flexible printed circuit board, and a polyimide membrane. All are covered with Parylene C for insulation and fusion bonding at assembly. A finite element method (FEM) model of the paraffin actuator is used to predict the resulting flow characteristics. The results show dispensing of well-defined volumes of 350 and 540 nL, with a good repeatability between dispensing sequences, as well as reproducibility between devices. In addition, the flow characteristics show no back-pressure dependence of the dispensed flow in the interval 0.5--2.0 MPa. The FEM model can be used to predict the flow characteristics qualitatively

  • 22.
    Bordas, Cloe
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Skupinski, Marek
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Öjefors, Erik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Lindeberg, Mikael
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Hjort, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    First results on a polyimide based ferromagnetic resonance microwave filter2004In: MEMSWAVE 2004, Uppsala, Sweden, 2004Conference paper (Other scientific)
  • 23.
    Bäcklund, Ylva
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science. Fasta tillståndets elektronik. 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, Electronics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science. Materialvetenskap. 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, Electronics.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science. Materialvetenskap. 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, Electronics.
    Stenmark, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science. ÅSTC. 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, Electronics.
    Micro sculpturing - Somewhat new materials and micromachining methods to meet new applications1999In: Eurosensors -99, 1999Conference paper (Other academic)
  • 24.
    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.

  • 25.
    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, 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.

  • 26.
    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, 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.

  • 27.
    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, 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.

  • 28.
    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, P19Conference paper (Refereed)
  • 29. 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)
  • 30.
    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, 144103- p.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%.

  • 31.
    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, 3765-3771 p.Article 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.

  • 32.
    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, 1946-1948 p.Conference paper (Refereed)
  • 33. 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)
  • 34.
    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)
  • 35.
    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)
  • 36.
    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)
  • 37.
    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)
  • 38.
    Chitica, N
    et al.
    MATERIALS SCIENCE/MST.
    Daleiden, J
    Bentell, J
    Andre, J
    Strassner, M
    Greek, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Pasquariello, Donato
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Gupta, Ram
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Fabrication of tunable InP/air-gap Fabry-Perot cavities by selective etching of InGaAs sacrificial layers1999In: Physica scripta. T, ISSN 0281-1847, Vol. T79, 131-134 p.Article in journal (Refereed)
    Abstract [en]

    We report the fabrication of InP/air-gap Fabry-Perot resonant cavities with an improved tunability characteristic achieved through the micromachining of more flexible suspended InP beams. The micromechanical structures are electrostatically actuated. A tuning range of 55 nm is demonstrated for an actuation voltage of 12 V. The low leakage current, of less than 10 µA for a bias of up to 30 V, provides a low actuation power. The tunable air-gap cavities are fabricated by selective wet etching of InGaAs sacrificial layers. An FeCl3 based etchant is used to completely remove the InGaAs material without affecting the thickness of the InP layer. The anisotropy of the etch rate of InGaAs was also investigated and exploited in the micromachining process.

  • 39.
    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)
  • 40.
    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, 301-310 p.Article 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. 

  • 41.
    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)
  • 42.
    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)
  • 43.
    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, 7601-7609 p.Article 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.

  • 44.
    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, 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.

  • 45.
    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).

  • 46.
    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.

  • 47.
    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 (Other academic)
  • 48.
    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.

  • 49.
    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.

  • 50.
    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)
12345 1 - 50 of 233
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