An aptamer-based fluorescence bio-sensor for chiral recognition of arginine enantiomers

Carboxyfluorescein (FAM) labeled aptamers have strong fluorescence. When no targets d, l-Arg existed, aptamer adsorbed on the negatively charged AuNps and the fluorescence intensity of aptamer was significantly quenched via fluorescence resonance energy transfer (FRET). Once added d, l-Arg into the sensing system, aptamer specifically combined with its targets (d, l-Arg) and scarcely absorbed onto AuNPs, resulted in the fluorescence recovery of aptamer and the aggregation of AuNps. But the recovered fluorescence intensity of l-Arg stronger than its enantiomer, d-Arg.98