LAUSR

Abstract Au or other metal nanostructures have the ability to strongly quench the fluorescence of fluorophores. This feature has made AuNP-conjugates attractive for the construction of platforms for various bioanalytes to overcome the limitations of small molecule fluorophores (poor solubility, long reaction time). In this paper, an ultrafast “Turn-On” fluorescent sensor for biothiols was constructed. The sensor is based on the fluorescent resonance energy transfer (FRET) effect between the fluorophore (PN) and AuNPs, which effectively quenches the fluorescence of the fluorophore. In the presence of thiols, PN is displaced and released from AuNP surfaces, and thus, the fluorescence is rapidly restored. The sensor features appreciable water solubility and ultrafast response time (a few seconds for Cys). In addition, it exhibits high selectivity and a detection limit as low as 12 nmol/L for Hcy. Moreover, the sensor presents good biocompatibility and has been successfully applied for imaging biothiols in living cells.