Abstract
AbstractA method for impedimetric detection of biomolecules with field‐effect transistor (FET) arrays is presented. For biomolecular detection, the corresponding molecules such as single‐stranded DNA or bovine serum albumine (BSA) were covalently immobilized to the gate structure of 16‐channel open‐gate FET devices. A micro spotter system was used to site‐selectively attach biomolecules to selected channels out of the array. The differential transistor transfer function (TTF) of the FETs with attached biomolecules compared to free FETs was recorded. With this impedimetric technique it was possible to reliably detect biomolecules, because the recordings were not disturbed by the typical long‐term drift of the sensors like in potentiometric readout mode. For transistor gates, where DNA sequences of different length were attached, small differences in the TTF spectra were detected. When BSA was covalently immobilized to the FETs clear differences in the TTF spectra were detected, which were independent on buffer pH variations around the isoelectric point of the protein. Based on the results presented in this article it can be concluded, that the TTF method detects passive components of the biomolecules like resistance and capacitance rather than surface charge effects. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Published Version
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