Silica-polydopamine Hybrids as Light‐induced Oxidase Mimic for Colorimetric Detection of Pyrophosphate
In this study, silica-polydopamine hybrids (SPDA) were fabricated by a facile and one-step heating method using dopamine and (3-Aminopropyl) triethoxysilane (APTES) as the reaction reagent. It was firstly found that the light illuminated-SPDA could oxidize colorless 3, 3', 5, 5'-tetramethylbenzidine (TMB) to produce blue ox-TMB. The coloration process was quenched very efficiently via the addition of Cu2+. The presence of pyrophosphate ion (PPi) with the solution of light-illuminated SPDA-Cu2+-TMB induced recovery of the coloration process. The recovery occured because PPi coordinated with Cu2+, effectively sequestering the ion from SPDA. A calibration curve was developed that related to the extent of absorption recovery to [PPi], making the SPDA-Cu2+-TMB system a sensitive and selective turn-on sensor for PPi. The limit-of-detection (LOD) for PPi was 0.06 μmol/L (S/N=3) with a linear dynamic range of 0.1-30 µmol/L and the calibration curve of linear equation was given as: y = 0.00146x + 0.05096(r = 0.9974). The proposed method has been successfully applied to the detection of PPi in human serum with satisfied recovery. The simplicity, low cost, high sensitivity, good reproducibility and excellent selectivity of the PPi detection platform based on the light‐induced oxidase mimic property of SPDA serves as an inspiration for further applications of SPDA in chemo/biosensing.