Abstract
Fluorescent probes are important tools in medical diagnosis, because they allow for rapid and sensitive monitoring target analytes. Although most fluorescent probes show excellent performance in clean buffers, they are easily foiled by nonspecific signals in complex real samples such as blood plasma. The problem is mainly caused by the nonspecific binding of fluorescent probes with other macromolecules. Furthermore, environment-sensitive dyes display weaker emission in aqueous buffers. Therefore, how to solve these two fundamental problems is an important issue. Previously, we’ve developed a BGSBD probe which exhibited dramatic fluorescence turn-on upon covalently labeled to SNAP-tag protein. Based on BGSBD, we design a novel protein-shield concept as demonstrated by SNAP-tag protein for fluorescence amplification and nonspecific signal suppression of fluorescence probes for detection of enzymes and reactive small molecules in blood plasma. Herein, we designed three different probes, BGSBD-NO2, BGSBD-N3 and BGSBD-(OH)2, to detect Nitroreductase (NTRase), Hydrogen Sulfide (H2S) and Hydrogen Peroxide (H2O2). We have successfully amplified the fluorescence signal and suppressed unspecific signal of the probes by our protein-shield strategy in human blood plasma.