Nanoporous gold film based immunosensor for label-free detection of cancer biomarker

Nanoporous gold (NPG) film modified electrode for the construction of novel label-free electrochemical immunosensor for ultrasensitive detection of cancer biomarker prostate specific antigen (PSA) is described. Due to its high conductivity, large surface area, and good biocompatibility, NPG film modified electrode was used for the adsorption of anti-PSA antibody (Ab). The sensing signal is based on the monitoring of the electrode's current response towards K3Fe(CN)6, which is extremely sensitive to the formation of immunocomplex within the nanoporous film. Under optimum conditions, the amperometric signal decreases linearly with PSA concentration (0.05–26 ng/mL), resulting in a low limit of detection (3 pg/mL). We demonstrated the application of the novel immunosensor for the detection of PSA in real sample with satisfactory results.