Template-engaged redox etching strategy synthesis of α-MnO_2 hollow architectures toward colorimetric glutathione sensing

摘要

Utilizing carbon spheres as templates, a redox etching strategy is designed to convert the carbon spheres into alpha-MnO2 hollow architectures, which show large surface area of similar to 70.1 m(2) g(-1) and mesoporous features. Note that the synthesized alpha-MnO2 as oxidase can catalyze the oxidization of 3,3',5,5'-tetramethylbenzidine (TMB), resulting in oxTMB with a characteristic absorption at 652 nm in UV-Vis spectrum. Glutathione (GSH) as antioxidant can be readily oxidized by alpha-MnO2 and thus the formation of oxTMB is suppressed as GSH introduces. Benefiting from these exciting results, we present an effective colorimetric sensor for GSH based on the synthesized alpha-MnO2 . The special architectures of alpha-MnO2 endow the colorimetric sensor displaying a wide working range over 0.01 to 15 mu M, a determination limit of 4.2 nM as well as significantly selectivity. More importantly, the reported colorimetric sensor exhibits a perfect reliability for GSH in human serum. This work not only explores a simple avenue to synthesis of hollow architectures, but also broadens the biosensing applications of metal oxides.