| 1. |
- Psoma, Sotiria D., et al.
(författare)
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A novel enzyme entrapment in SU-8 microfabricated films for glucose micro-biosensors
- 2010
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 26:4, s. 1582-1587
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Tidskriftsartikel (refereegranskat)abstract
- The present work investigates the utilisation of the widely used SU-8 photoresist as an immobilisation matrix for glucose oxidase (GOx) for the development of glucose micro-biosensors. The strong advantage of the proposed approach is the simultaneous enzyme entrapment during the microfabrication process within a single step, which is of high importance for the simplification of the BioMEMS procedures. Successful encapsulation of the enzyme GOx in "customised" SU-8 microfabricated structures was achieved through optimisation of the one-step microfabrication process. Although the process involved contact with organic solvents, UV-light exposure, heating for pre- and post-bake and enzyme entrapment in a hard and rigid epoxy resin matrix, the enzyme retained its activity after encapsulation in SU-8. Measurements of the immobilised enzymes activity inside the SU-8 matrix were carried out using amperometric detection of hydrogen peroxide in a 3-electrode setup. Films without enzyme showed negligible variation in current upon the addition of glucose, as opposed to films with encapsulated enzyme which showed a very clear increase in current. Experiments using films of increased thickness or enzyme concentration, showed a higher response, thus proving that the enzyme remained active not only on the films surface, but also inside the matrix as well. The proposed enzyme immobilisation in SU-8 films opens up new possibilities for combining BioMEMS with biosensors and organic electronics.
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| 2. |
- Briand, D., et al.
(författare)
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Low-power micromachined MOSFET gas sensor
- 2000
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Ingår i: Journal of microelectromechanical systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1057-7157 .- 1941-0158. ; 9:3, s. 303-308
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the design, fabrication, and characterization of the first low-power consumption MOSFET gas sensor. The novel MOSFET array gas sensor has been fabricated using anisotropic bulk silicon micromachining. A heating resistor, a diode used as temperature sensor, and four MOSFETs are located in a silicon island suspended by a dielectric membrane. The membrane has a low thermal conductivity coefficient and, therefore, thermally isolates the electronic components from the chip frame. This low thermal mass device allows the reduction of the power consumption to a value of 90 mW for an array of four MOSFETs at an operating temperature of 170 °C. Three of the MOSFETs have their gate covered with thin catalytic metals and are used as gas sensors. The fourth one has a standard gate covered with nitride and could act as a reference. The sensor was tested under different gaseous atmospheres and has shown good gas sensitivities to hydrogen and ammonia. The low-power MOSFET array gas sensor presented is suitable for applications in portable gas sensor instruments, electronic noses, and automobiles.
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| 3. |
- Briand, D., et al.
(författare)
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Modulated operating temperature for MOSFET gas sensors : Hydrogen recovery time reduction and gas discrimination
- 2003
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Ingår i: Sensors and actuators. B, Chemical. - 0925-4005 .- 1873-3077. ; 93:1-3, s. 276-285
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This communication presents a modulated mode of operation for MOSFET gas sensors. A low-power micromachined device allows pulsing the temperature of MOSFET gas sensors with a time constant less than 100ms. Modulating the temperature during the gas exposure modifies the kinetics of the gas reactions with the sensing film. The way the sensor response is modified by the temperature modulation depends on the sensor "history", on the nature of the surrounding gaseous atmosphere, and on the type of materials used as catalytic sensing film. Pulsing the temperature up just after the gas exposure can reduce the recovery time for specific applications, such as for hydrogen detection. Cycling the temperature can allow the discrimination between different gas mixtures. Discrimination was shown for gaseous mixtures of hydrogen and ammonia in air. The results obtained indicate that a "smart" combination of sample and temperature profile could be used to expand the information content in the sensor response. © 2003 Elsevier Science B.V. All rights reserved.
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| 4. |
- Briand, D., et al.
(författare)
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Thermally isolated MOSFET for gas sending application
- 2001
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Ingår i: IEEE Electron Device Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 0741-3106 .- 1558-0563. ; 22:1, s. 11-13
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Tidskriftsartikel (refereegranskat)abstract
- This work reports on thermally isolated electronic components for gas sensing applications. The device is composed of an array of 4 MOSFET, a diode and a semiconductor resistor integrated on a micro-hotplate, which is fabricated using bulk micromachining of silicon. The thermal efficiency of the device is 2°C/mW with a thermal constant less than 100 ms. Holes are made in the passivation film over the gates of the MOSFET and gas sensitive films deposited on top of the gate insulator. The low thermal mass device realized allows new modes of operation for MOSFET gas sensors such as a combination of the field and thermal effects and a pulsed temperature mode of operation.
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| 5. |
- Korrel, Maarten, et al.
(författare)
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Minimally invasive versus open distal pancreatectomy: an individual patient data meta-analysis of two randomized controlled trials
- 2021
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Ingår i: HPB. - : ELSEVIER SCI LTD. - 1365-182X .- 1477-2574. ; 23:3, s. 323-330
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Forskningsöversikt (refereegranskat)abstract
- Background: Minimally invasive distal pancreatectomy (MIDP) has been suggested to reduce postoperative outcomes as compared to open distal pancreatectomy (ODP). Recently, the first randomized controlled trials (RCTs) comparing MIDP to ODP were published. This individual patient data meta analysis compared outcomes after MIDP versus ODP combining data from both RCTs. Methods: A systematic literature search was performed to identify RCTs on MIDP vs. ODP, and individual patient data were harmonized. Primary endpoint was the rate of major (Clavien-Dindo > III) complications. Sensitivity analyses were performed in high-risk subgroups. Results: A total of 166 patients from the LEOPARD and LAPOP RCTs were included. The rate of major complications was 21% after MIDP vs. 35% after ODP (adjusted odds ratio 0.54; p = 0.148). MIDP significantly reduced length of hospital stay (6 vs. 8 days, p = 0.036), and delayed gastric emptying (4% vs. 16%, p = 0.049), as compared to ODP. A trend towards higher rates of postoperative pancreatic fistula was observed after MIDP (36% vs. 28%, p = 0.067). Outcomes were comparable in high-risk subgroups. Conclusion: This individual patient data meta-analysis showed that MIDP, when performed by trained surgeons, may be regarded as the preferred approach for distal pancreatectomy. Outcomes are improved after MIDP as compared to ODP, without obvious downsides in high-risk subgroups.
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