Biosynthesized Quantum Dot for Facile and Ultrasensitive Electrochemical and Electrochemiluminescence Immunoassay.

Nanomaterials are commonly utilized for amplified immunoassay of biomarkers. However, traditional nanomaterial-based immunoassay usually requires a time-consuming and labor-intensive nanoparticle modification and conjugation process, which impedes their practical applications. Here, a new immunoassay method based on biosynthesized nanomaterials is developed with versatile functions for facile and ultrasensitive detection of cancer biomarker. In this method, the utilized biosynthesized quantum dots (BQDs) allow convenient antibody conjugation and electrode modification, and demonstrate excellent electrochemical and electrochemiluminescent responses. The differential pulse voltammetric, faradaic impedance spectroscopy, and electrochemiluminescent measurements with the BQD-modified electrode show detection limits at picomolar levels as well as good specificity toward human prostate-specific antigen detection. The inherent recognization capability as well as the inherent electrochemical and electrochemiluminescence features thus enable BQDs as good candidates for facile immunosensors with high sensitivity. Such a biosynthesized nanomaterial-based approach opens up the possibility of using innovative designs for nanoparticle-based assays, and developing reliable and practical methods for early disease diagnosis.