This research reports a new approach with lectin-based capacitive non-faradaic biosensor for the detection of prostate-specific membrane antigen (PSMA) as a promising diagnostic marker for determining prostate cancer. PSMA expression is significantly higher in malign hyperplasia, thus can be effectively employed to discriminate other benign prostatic diseases. Herein, the aluminium interdigitated electrode was fabricated and modified by a linker, 2-mercaptoacetate to form the self-assembled monolayer. Gold nanoparticles were used as a signal amplifier and supported the conjugation of Concanavalin A, for efficient capacitive sensing of PSMA. Scanning electron microscope observation effectively captured the surface modification on the aluminium surface by revealing the specific adherence of gold nanoparticles with Concanavalin A. Moreover, the successful surface modification was further validated by atomic force microscopy, Fourier transforms infrared spectroscopy, and X-ray photoelectron spectroscopy. The interaction analysis of Concanavalin A with PSMA by capacitive non-faradaic measurement exhibited a linear detection range from 10 pM to 100 nM and attained the detection limit and sensitivity of 10 pM and 1.65 nF/pM respectively as the comparable performance to the current sensing strategies. Furthermore, the fabrication and quantification of PSMA as demonstrated here are relatively simple and can be employed for the straightforward detection of other biomarkers.
