Abstract

Biosensors with Capacitive Field-Effect Devices – Selected Examples

Michael Schöning, Director of Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences

Among the multitude of concepts and different types of chemical sensors and biosensors discussed in literature, the strategy to integrate chemical or biological recognition elements together with semiconductor-type field-effect devices is one of the most attractive approaches. In this context, two examples of capacitive field-effect devices (FEDs), which have been developed recently in our institute, will be presented:

[a]. A DNA- (deoxyribonucleic acid) based FED modified with a positively charged weak polyelectrolyte layer has been applied for the electrical detection of DNA immobilization and hybridization by the intrinsic molecular charge. This biosensor is able to detect the existence of target DNA amplicons in PCR (polymerase chain reaction) samples and thus, can be used as tool for a quick verification of DNA amplification and the successful PCR process.

[b]. As a second example, a TMV- (tobacco mosaic virus) modified FED for penicillin detection is presented. The TMV nanotubes serve as enzyme nanocarriers, enabling the immobilization of a high amount of enzymes without substantial loss of their activity, which results in an enhanced biosensor performance. This approach has been experimentally demonstrated by realizing a penicillin biosensor using TMV nanotubes functionalized with the enzyme penicillinase as a model system.