In this thesis, a recently introduced Silicon-on-Insulator (SOI) based thin film resistor is employed for the label-free detection of molecules by their intrinsic charge. Polyelectrolytes of opposite charge can be adsorbed alternately to the sensor surface, forming self-assembled polyelectrolyte multilayers (PEMs). Differently charged polyelectrolytes adsorbing to the sensor surface result in defined potential shifts, which can be monitored in real time. To allow for a quantitative analysis of the sensor response, we have developed a theoretical description. In addition, we have employed the SOI based field effect device as a biosensor. To this end, we have developed a novel technique for the detection of enzymatic activity. We have found that the adsorption of polyelectrolytes, as opposed to charged monomers or short oligomers, can be readily observed by the sensor. Enzymes, which cleave polyelectrolyte substrates, are therefore detected by a decrease of the polyelectrolyte signal.
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In this thesis, a recently introduced Silicon-on-Insulator (SOI) based thin film resistor is employed for the label-free detection of molecules by their intrinsic charge. Polyelectrolytes of opposite charge can be adsorbed alternately to the sensor surface, forming self-assembled polyelectrolyte multilayers (PEMs). Differently charged polyelectrolytes adsorbing to the sensor surface result in defined potential shifts, which can be monitored in real time. To allow for a quantitative analysis of t...
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