A novel dual-functional biosensor for fluorometric detection of inorganic pyrophosphate and pyrophosphatase activity based on globulin stabilized gold nanoclusters

Key Words:Dual-functional biosensor; Gold nanoclusters; Off on off; Competitive response; Fluorescence

Abstract:A novel ultrasensitive dual-functional biosensor for highly sensitive detection of inorganic pyrophosphate (PPi) and pyrophosphatase (PPase) activity was developed based on the fluorescent variation of globulin protected gold nanoclusters (Glo@Au NCs) with the assistance of CO+. Glo@Au NCs and PPi were used as the fluorescent indicator and substrate for PPase activity evaluation, respectively. In the presence of Cu2+, the fluorescence of the Glo@Au NCs will be quenched owing to the formation of Cu2+_Glo@Au NCs complex, while PPi can restore the fluorescence of the Cu2+-Glo@Au NCs complex because of its higher binding affinity with Cu2+. As PPase can catalyze the hydrolysis of PPi, it will lead to the release of Cu2+ and re-quench the fluorescence of the Glo@Au NCs. Based on this mechanism, quantitative evaluation of the PPi and PPase activity can be achieved ranging from 0.05 mu M to 218.125 mu M for PPi and from 0.1 to 8 mU for PPase, with detection limits of 0.02 mu M and 0.04 mU, respectively, which is much lower than that of other PPi and PPase assay methods. More importantly, this ultrasensitive dual functional biosensor can also be successfully applied to evaluate the PPase activity in human serum, showing great promise for practical diagnostic applications. (C) 2016 Elsevier B.V. All rights reserved.

Volume:958

Translation or Not:no