Ultrasensitive electrochemical biosensor based on MXene quantum dots for prostate cancer biomarker detection

Prostate cancer (PSA) is among the leading causes of men's deaths worldwide and needs extremely sensitive and cost-effective diagnostic tools. In this study, an electrochemical immunosensor enhanced by polyaniline-loaded MXene quantum dots and gold nanoparticles (PANI@Ti₃C₂ MXene Quantum dots-Au NPs) was constructed for highly sensitive prostate-specific antigen (PSA) detection at femtogram levels. The sensor employs V₂C MXene quantum dots gold-nanoparticle-decorated as signal tags to remarkably enhance electron transfer efficiency and detection sensitivity. A sandwich immunoassay strategy using MXene quantum dots gave superior selectivity and quantitation accuracy of PSA. The optimized immunosensor exhibited a large linear detection range of 2 fg mL^{- 1} -2 pg mL^{- 1} with a fantastic detection limit of 0.61 fg mL^{- 1}. Electrochemical characterization was performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) to confirm successful sensor fabrication and electron transfer dynamics, while differential pulse voltammetry (DPV) was employed for quantitative detection of PSA. Human serum sample validation demonstrated the clinical applicability of the platform with the presence of high specificity, reproducibility, and analytical stability. The findings place MXene quantum dots as serious contenders for next-generation biosensing technologies with a robust, scalable approach to early diagnosis of prostate cancer.