Aggregation Induced Emission Fluorogen-Based Label-Free Biosensor for Highly Sensitive Detection of Carcinoembryonic Antigen

Abstract

Abstract A highly sensitive and label-free fluorescence carcinoembryonic antigen (CEA) biosensor was developed via the target-triggered enzymatic recycling amplification reaction. To design this strategy, aggregation induced emission fluorogen (AIEgen) TPE-M was chosen as a signal reporter to enhance the detection efficiency, and L-cysteine (L-Cys) was utilized as a reactant to control over the fluorescence intensity due to its distinct capability of reacting with TPE-M and hemin/G-quadruplex. CEA triggered the in-situ generation of abundant hemin/G-quadruplex through polymerase/nicking enzyme-assisted recycling amplification, and the generated hemin/G-quadruplex could catalyze destruction of L-Cys. With L-Cys consuming, a significant decrease in fluorescence intensity was observed, demonstrating that the fluorescence intensity was indirectly relied on the CEA amount. As a consequence, a facile, precise and sensitive strategy for CEA assay was readily realized. Furthermore, the detection limit was 0.033 fmol/L (S/N = 3). The developed AIEgen-based biosensor provided a new method for the sensitive and reliable detection of CEA in biological liquids, thus displaying a significant promise for the CEA-related disease diagnosis.