A rationally designed triple-qualitative and double-quantitative high precision multi-signal readout sensing platform

Abstract

Single mode sensing is more likely suffers from false positive or negative results than multi-signal readout assay. By using a layer-by-layer modified ITO/Au/BiOI electrode as the matrix and core/shell upconversion nanoparticles (UCNPs) as the signal labels, a triple-qualitative (smartphone based naked-eye readout, photoelectrochemical (PEC) and fluorescence (FL)) and double-quantitative (PEC and FL) multi-signal readout sensing platform was designed for high-precision assay of prostate-specific antigen (PSA), a biomarker for prostate cancer diagnosis. Based on the PSA bio-recognition events, the PEC mode sensing was achieved, while the specific enzymatically active of PSA for 5-Carboxyfluorescein (FAM) labeled helix peptide (CGHSSKLQK-FAM) enabled the FL sensing. Besides, under the excitation of 980 nm near-infrared (NIR) laser, the signal antibody@UCNPs bioconjugates can emit visible light for smartphone based naked-eye readout. Compared with the single-signal method, the accuracy of PSA serodiagnosis was obviously improved. Moreover, the above procedure could be extended to the single-molecule fluorescence counting method, the limit of detection for PSA can reach 0.005 ag/mL (S/N = 3). This work combined the advantages of different techniques, minimized the misdiagnose detection, and provides a rational design idea for multi-signal readout sensing platform.