Au nanoparticle-modified DNA sensor based on simultaneous electrochemical impedance spectroscopy and localized surface plasmon resonance

• DNA sensor with electrodeposited Au nanoparticles on ITO surface.
• Dual detection capability with EIS and LSPR on the same surface.
• Optimization of electrodeposition using LSPR and SEM.
• Sensitive detection of a point mutation in ApoE gene.

Electrochemical impedance spectroscopy (EIS) and localized surface plasmon resonance (LSPR) were performed on the same Au nanoparticle (AuNP)-modified indium tin oxide (ITO) coated glass surfaces. Cyclic voltammetry was applied to electrodeposit AuNPs on ITO surface directly. The surface plasmon band characterization of AuNPs was initially studied by controlling the electrodeposition conditions. It was found that the size of AuNP clusters was significantly affected by the applied potential and KCl concentration in solution. The dual-detection platform was applied to detect DNA hybridization related to a specific point mutation in apolipoprotein E gene (ApoE), which was related to the progression of Alzheimer's disease. The preliminary results facilitate the development of a versatile biosensor that can be easily miniaturized and integrated into a high-throughput diagnostic device.