2-D/2-D heterostructured biomimetic enzyme by interfacial assembling Mn3(PO4)2 and MXene as a flexible platform for realtime sensitive sensing cell superoxide
Shen Fei Zhao, Fang Hu, Zhuan Zhuan Shi, Jing Fu, Yue Chen, Fang Dai, Chunxian Guo, Chang Ming Li
Abstract
It is critical for fabricating flexible biosensors with both high sensitivity and good selectivity to realize real-time monitoring superoxide anion (O2•−), a specific reactive oxygen species that plays critical roles in various biological processes. This work delicately designs a Mn3(PO4)2/MXene heterostructured biomimetic enzyme by assembling two-dimensional (2-D) Mn3(PO4)2 nanosheets with biomimetic activity and 2-D MXene nanosheets with high conductivity and abundant functional groups. The 2-D nature of the two components with strong interfacial interaction synergistically enables the heterostructure an excellent flexibility with retained 100% of the response when to reach a bending angle up to 180°, and 96% of the response after 100 bending/relaxing cycles. It is found that the surface charge state of the heterostructure promotes the adsorption of O2•−, while the high-energy active site improves electrochemical oxidation of O2•−. The Mn3(PO4)2/MXene as a sensing platform towards O2•− achieves a high sensitivity of 64.93 µA·µM−1·cm−2, a wide detection range of 5.75 nM to 25.93 µM, and a low detection limit of 1.63 nM. Finally, the flexible heterostructured sensing platform realizes real-time monitoring of O2•− in live cell assays, offering a promising flexible biosensor towards exploring various biological processes.