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BP: Fachverband Biologische Physik

BP 14: Poster Session I

BP 14.17: Poster

Dienstag, 18. März 2025, 10:00–12:30, P3

G-FETs for label-free biosensing of protein interactions — •Florian Steinbach, Mykola Fomin, Margarete Schwirblat, and Carola Meyer — Institute of Physics, University of Osnabrück, Germany

Graphene field-effect transistors (G-FETs) offer a promising approach for label-free biosensing due to their sensitivity and compatibility with liquid environments. In this work, we investigate liquid-gated G-FETs functionalized with lipid monolayers for detecting protein interactions at membrane interfaces.

The fabrication process was refined to improve device stability and reduce measurement variability. To enable reusability, we employed tris-NTA-functionalized lipids, allowing reversible binding and elution of hexahistidine (H6)-tagged proteins while preserving device functionality for subsequent detection cycles. Adjustments to the functionalization protocol included histidine-based elution, which better preserved the passivation layer compared to standard imidazole methods. Electrical measurements were used to monitor functionalization steps and protein interactions. Using monomeric enhanced green fluorescent protein (H6-mEGFP) as a model system, we present characteristic shifts and changes in transconductance during each step of the protocol.

These developments contribute to the optimization of G-FETs for biosensing applications, with particular attention to the stability of functionalized interfaces under physiological conditions. The findings will be discussed in the context of improving sensor design and extending the approach to more complex biomolecular systems.

Keywords: Graphene Field-Effekt Transistors; Label-Free Biosensing; Proteins; Lipid layer; Electronic transport