Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 17: Interfaces and surfaces

HL 17.7: Vortrag

Montag, 11. März 2013, 16:30–16:45, H15

AlGaN/GaN Enzyme-Modified Field-Effect Transistors for Analysis of Enzyme Functionality — •Gesche Mareike Müntze, Wladimir Schäfer, Kai Röth, Alexander Sasse, and Martin Eickhoff — I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Germany

AlGaN/GaN high electron mobility transistors (HEMTs) are promising candidates for the application as transducers in biosensors. The chemical stability and biocompability of GaN surfaces as well as their high pH-sensitivity serve as the basis for this application. By covalent immobilization of enzymes on the gate area of an AlGaN/GaN HEMT one obtains an enzyme-modified field-effect transistor (EnFET) with the type of enzyme defining the specificity of the biosensor. Essential to this concept is the formation of an acid or a base as a product of the enzymatic reaction. The pH-change is detected by the AlGaN/GaN HEMT in terms of a change in the drain-source current I_DS.

Here, we report the preparation of penicillinase-modified as well as acetylcholinesterase-modified FETs (PenFETs, AcFETs) by a wet chemical process. The obtained EnFET response curves can be fitted by applying a kinetic model which is used to extract microscopic parameters representing both the enzymatic activity and the transistor/enzyme/electrolyte system.

Our results show that EnFETs based on AlGaN/GaN HEMT structures provide a suitable base not only for the realization of specific biosensors but also for analysis of the functionality of immobilized enzymes.