Surface Plasmon Coupled Fluorescence-Enhanced Interfacial “Molecular Beacon” To Probe Biorecognition Switching: An Efficient, Versatile, and Facile Signaling Biochip

Integrating probes and a substrate together, a fluorescence-enhanced interfacial “molecular beacon” (FEIMB) is demonstrated, based on directional surface plasmon coupled emission. Through this simple yet efficient interfacial modulation engineering to create an interfacial quencher (graphene oxide)–enhancer (gold nanofilm) pair, the quenching-to-enhancing region of FEIMB can be actively tuned. Therefore, it provides a spatial match between signal transduction and interface-mediated biorecognition switching. Via combination of strong quenching and efficient plasmonic coupling, a synergistically amplified signal-to-background ratio of >1000-fold has been achieved. FEIMBs have been employed in protein and DNA detection, creating a high-performance and universal chip-based plasmon-mediated fluorescence sensing platform.