Luminescent gold nanocluster-based sensing platform for accurate H_(2)S detection in vitro and in vivo with improved anti-interference

Gold nanoclusters(Au NCs)are promising luminescent nanomaterials due to their outstanding optical properties.However,their relatively low quantum yields and environment-dependent photoluminescence properties have limited their biological applications.To address these problems,we developed a novel strategy to prepare chitosan oligosaccharide lactate(Chi)-functionalized Au NCs(Au NCs@Chi),which exhibited emission with enhanced quantum yield and elongated emission lifetime as compared to the Au NCs,as well as exhibited environment-independent photoluminescence properties.In addition,utilizing the free amino groups of Chi onto Au NCs@Chi,we designed a FRET-based sensing platform for the detection of hydrogen sulfide(H_(2)S).The Au NCs and the specific H_(2)S-sensitive merocyanine compound were respectively employed as an energy donor and acceptor in the platform.The addition of H_(2)S induced changes in the emission profile and luminescence lifetime of the platform with high sensitivity and selectivity.Utilization of the platform was demonstrated to detect exogenous and endogenous H_(2)S in vitro and in vivo through wavelength-ratiometric and time-resolved luminescence imaging(TLI).Compared to previously reported luminescent molecules,the platform was less affected by experimental conditions and showed minimized autofluorescence interference and improved accuracy of detection.