Abstract
In recent years, small molecule fluorescent turn-on probes are getting much attention as they allow for sensitive, simple and specific detection with high signal-to-background ratios. Currently most of the small-molecule fluorescent turn-on probes are designed for monitoring proteins and reactive small molecules. Although most fluorescent probes show excellent performance in aqueous buffers, their application in protein rich human blood remain challenging as the real signal is usually obscured by nonspecific fluorescence. Herein, we introduce a novel protein-shield concept to eliminate nonspecific fluorescence in protein rich blood samples. Based on this concept, we reveal that modified fluorescent probes conjugated to target protein can generate very specific fluorescence signals in blood serum by blocking out nonspecific binding of the dyes with other nonspecific blood proteins. By this protein-shield concept, we’ve successfully designed probe BTCCVJ- N3, BGCCA- N3 and BTCCVJ-NO2 to detect Nitroreductase (NTRase) and Hydrogen Sulfide (H2S) with fluorescence signal amplification and removal of nonspecific fluorescence signals.