2-D/2-D heterostructured biomimetic enzyme by interfacial assembling Mn_(3)(PO_(4))_(2) and MXene as a flexible platform for realtime sensitive sensing cell superoxide

It is critical for fabricating flexible biosensors with both high sensitivity and good selectivity to realize real-time monitoring superoxide anion(O_(2)^(·−)),a specific reactive oxygen species that plays critical roles in various biological processes.This work delicately designs a Mn_(3)(PO_(4))_(2)/MXene heterostructured biomimetic enzyme by assembling two-dimensional(2-D)Mn_(3)(PO_(4))_(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 O_(2)^(·−),while the high-energy active site improves electrochemical oxidation of O_(2)^(·−).The Mn_(3)(PO_(4))_(2)/MXene as a sensing platform towards O2•−achieves a high sensitivity of 64.93µA·µM^(−1)·cm^(−2),a wide detection range of 5.75 nM to 25.93µM,and a low detection limit of 1.63 nM.Finally,the flexible heterostructured sensing platform realizes real-time monitoring of O_(2)^(·−)in live cell assays,offering a promising flexible biosensor towards exploring various biological processes.