Swelling induced electrical detections and photo-induced current analysis in reduced graphene oxide for novel biosensing mechanisms

Reactivity of reduced graphene oxide (rGO)-based biosensors depends on the size of target biomaterial. Graphene oxide (GO) contains functional groups like carboxyl groups on its surface, which interact with target biomolecules such as proteins through immobilization of receptors. These interactions are detected through changes in the electrical properties of rGO. Additionally, smaller biomaterials can penetrate the layers of the rGO network, further altering the biosensor's electrical conductivity. The study uses various biomaterials, including protein biomarkers and chlorine ions, demonstrating that small chlorine ions can be detected within the rGO network. Light defect and ellipsometry analyses confirm that while chlorine ions are detected inside the network, the biomarkers react externally with the surface functional groups. These findings suggest that rGO-based biosensors can exhibit different detection mechanisms depending on the size and nature of the target molecules.