Dual signal amplification photoelectrochemical biosensor for highly sensitive human epidermal growth factor receptor-2 detection.

Photoelectrochemical (PEC) biosensor for highly sensitive detection of breast cancer biomarker human epidermal growth factor receptor-2 (HER2) is reported utilizing a dual signal amplification strategy. The biosensor was prepared based on tungsten sulfide nanowire array on Ti mesh (WS2 NW/TM). Such WS2 NW/TM electrode can generate photoelectric signal under visible light excitation. The HER2 aptamer was wrapped onto the nanowire array surface for specific binding with HER2 molecules, and gold nanoparticles (Au NPs) that modified with glucose oxidase (GOx) and HER2 binding peptide was utilized for signal amplification. The H2O2 that generated by GOx catalyzed glucose reaction and localized surface plasmon resonance of Au NPs can both enhance the PEC current intensity of the biosensor, leading to dual signal amplification. The PEC current intensity is enhanced linearly with HER2 concentration in the 0.5-10 ng/mL range with limit of detection of 0.36 ng/mL. Such biosensor was applied for the detection of HER2 in breast cancer serum samples with detection results in good agreement with commercial ELISA results.