Versatile Electrochemical Platform Developed By Pyrophosphatase-Guided Triggered-Release System Based on Cu(II) Coordination

Abstract

Herein, a versatile electrochemical platform is constructed based on Cu(II) coordination by pyrophosphatase (PPase)-guided triggered-release system. The unique design of “homogeneous bio-enzyme catalytic reaction, but simple electrochemical interface modification” is involved. Firstly, we prepare a nucleic acid-like coenzyme A-Cu(II) coordination polymer (CoA-Cu(II) CP), which displays unique electrocatalytic oxidation to o-phenylenediamine (OPD). Secondly, the complex of pyrophosphate (PPi) and Cu(II) (PPi-Cu(II) complex) is formed well, which has a huge influence on the formation of CoA-Cu(II) CP. Next, PPi-Cu(II) complex can be broken along with the addition of PPase, which can catalyze the hydrolysis of PPi into Pi to release Cu(II), but NaF can also reverse the result. Under optimal conditions, the SWV response is virtually proportional to the content of PPi and the activity of the PPase, and the detection of limit is 30 nM and 0.65 mU/L, respectively (S/N = 3). Furthermore, the biosensor is successfully applied for the quantitative detection of PPase in complex samples with recoveries ranging from 98.8% to 102.0% with acceptable RSDs. This proposed method is sensitive, selective, stable and convenient without any labels or complicated operations, which provides a significant reference for PPi/PPase-based biological process and clinical determination.