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TU Dresden » Faculty of Mechanical Science and Engineering » Institute for Materials Science » Chair of Materials Science and Nanotechnology

Friday, 06 November 2009
(at 09:20 in room 115, Hallwachsstr. 3)
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Hydrogel-based piezoresistive biochemical microsensors for real time monitoring of organic and inorganic analytes

Margarita Günther

Solid-State Electronics Lab (IFE)
Technische Universität Dresden

The application of "stimuli-responsive" or "smart" cross-linked polymeric hydrogels in biochemical sensors is based on their ability to a phase transition under the influence of external excitations (pH, concentration of additives in water, temperature). Combining a smart hydrogel and a micro fabricated pressure sensor chip in piezoresistive biochemical sensors allows to continuously monitor the analyte-dependent swelling of a hydrogel and hence the analyte concentration in ambient aqueous solutions. The sensitivity of hydrogels with regard to the concentration of such additives as H+-ions (pH sensor), transition-metal ions, salts, organic compounds and proteins in water was investigated at different temperatures. It has been demonstrated that the sensor's sensitivity depends on the polymer composition as well as on the polymer cross-linking degree. A higher sensitivity was observed for polyelectrolyte hydrogels with higher concentrations of ionizable groups. Gel stiffening was observed in the presence of protein in the solution by means of both a hydrogel-based biochemical sensor and an AFM cantilever. Not only the measuring principle was adapted to different species in aqueous solutions but also the implemented sensor has been used as an instrument for the investigation of the gel sensitivity to different external stimuli and for on-line monitoring of the gel behaviour kinetics. The measured kinetic curves have been analysed by means of appropriate models and some methods improving the properties of the chemical sensors have been proposed. The polymer film preparation conditions and measurement conditions, which are necessary for high signal reproducibility and high long-term stable sensor sensitivity, were determined.

Brief Bio:

Margarita Guenther received her Ph.D. in physics of semiconductors and dielectrics from Kiev State University, Ukraine, in 1988. Since 1999 she has been Research assistant at the Solid-State Electronics Lab of the Dresden University of Technology. Her current research interests include the preparation of free-standing polymer films, polymer films on thin silicon membranes and silicon wafers, ion beam modification of active polymer layers for sensor function design, comprehensive characterization of polymer films (chemical-structural, mechanical and electrical properties; ellipsometry, FTIR, ESCA, SAW, AFM, nanoindentation measurements), application of sensitive polymer layers in gas and humidity piezoresistive sensors as well as in biochemical sensors based on hydrogels.

Invited by G. Cuniberti

last modified: 2021.10.21 Thu
author: webadmin