Surface‐Plasmonic‐Field‐Induced Photoredox Catalysis and Mediated Electron Transfer for Washing‐Free DNA Detection

Abstract

Distance-dependent electromagnetic radiation and electron transfer have been commonly employed in washingfree fluorescence and electrochemical bioassays,r espectively. In this study,w ec ombined the two distance-dependent phenomena for sensitive washing-free DNAd etection. A distance-dependent surface plasmonic field induces rapid photoredox catalysis of surface-bound catalytic labels,a nd distance-dependent mediated electron transfer allows for rapid electron transfer from the surface-bound labels to the electrode. An optimal system consists of achemically reversible acceptor (Ru(NH 3) 6 3+), ac hemically reversible photoredoxc atalyst (eosin Y), and ac hemically irreversible donor (triethanolamine). Side reactions with O 2 do not significantly decrease the efficiency of photoredox catalysis.E nergy transfer quenching between the electrode and the label can be lowered by increasing the distance between them. Washing-free DNA detection had ad etection limit of approximately 0.3 nm in buffer and 0.4 nm in serum without aw ashing step.