Template-engaged redox etching strategy synthesis of α-MnO2 hollow architectures toward colorimetric glutathione sensing

Abstract Utilizing carbon spheres as templates, a redox etching strategy is designed to convert the carbon spheres into α-MnO2 hollow architectures, which show large surface area of ~70.1 m2 g−1 and mesoporous features. Note that the synthesized α-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 α-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 α-MnO2. The special architectures of α-MnO2 endow the colorimetric sensor displaying a wide working range over 0.01 to 15 μM, 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.