Dual-color quantum dots nanobeads based suspension microarray for simultaneous detection of dual prostate specific antigens

Abstract

Featured with high multiplexibility, suspension microarray technology usually involves the conjugation of second-antibody with organic dye based fluorescent proteins, which are inherently unsuitable for multicolor signaling under single wavelength excitation. In addition, application of single QDs-based fluorescent reporter in suspension microarray is dramatically hampered since its preparation often suffers from poor reproducibility and stability. Herein, a novel suspension microarray system based on dual color quantum dots (QDs) nanobead as fluorescence label was developed for simultaneous detection of prostate specific antigen (PSA) biomarkers. When both antigens are present in sera sample, free (f)-PSA antibody-conjugated green and complexed (c)-PSA antibody-conjugated red QDs nanobeads would be both specifically absorbed onto the surface of total PSA antibody-conjugated magnetic beads, leading to the formation of magnetic fluorescent hybrid that can be purified from the mixture by an external magnet prior to flow cytometry analysis. The proposed method demonstrates simultaneous detection ability for f- and c- PSA antigen assay with high detection sensitivity that is comparable to clinical approaches including ELISA and chemiluminescence assay. Furthermore, result of clinical application of the proposed method is consistency with clinical data, demonstrating its potential in suspension microarray for accurate prostate cancer diagnosis.