A Cu(ii) coordination polymer-based catalytic sensing system for detecting cysteine and sulfur anions

Abstract

Developing metal coordination polymer (CP)-based artificial enzyme mimics for establishing novel bio-chemosensing systems is important due to their high catalytic activity. Herein, a Cu(II)-based CP (Cu-aspartic acid CP, that is Cu-Asp CP) was successfully prepared by a simple interface growth method. It was found that the as-prepared Cu-Asp CP has excellent peroxidase-like activity for 3,3′,5,5′-tetramethylbenzidine (TMB) as the substrate in the presence of H₂O₂. On the basis of these findings, taken together with high complexing stability constants between Cu²⁺ ions and cysteine (Cys)/S²⁻ anions, simple, highly sensitive and selective colorimetric assays for detecting Cys and S²⁻ anions were successfully developed, with low limits of detection estimated to be 0.625 μM and 0.206 μM, respectively.