Nanostructured MXene-based biomimetic enzymes for amperometric detection of superoxide anions from HepG2 cells

A novel MXene-based biomimetic enzyme was synthesized using adenosine triphosphate (ATP) as a template to modify a Mn 3 (PO 4 ) 2 nanostructure on Mxene-Ti 3 C 2 nanosheets. The resulting composite was used as an electrode material in an electrochemical sensor for superoxide anion (O 2 •− ). It displays excellent catalytic properties which is attributed to the synergistic effects of the two-dimensional conductive substrate and the Mn 3 (PO 4 ) 2 nanoparticles. The addition of ATP results in the formation of a porous and ordered nanostructure of Mn 3 (PO 4 ) 2 . This facilitates the electron transfer between O 2 •− and electrode. The sensor, best operated at 0.75 V (vs. Ag/AgCl), displays a rapid amperometric response with a detection limit of 0.5 nM and an analytical range that extends from 2.5 nM to 14 μM. Conceivably, it has potential in the detection of O 2 •− released by living cells. Graphical abstract Nanostructured MXenes were synthesized by in-situ growth of Mn 3 (PO 4 ) 2 on Ti 3 C 2 nanosheets under the induction of adenosine triphosphate (ATP). They display enzyme mimickong properties. A sensor fabricated with the composites can be used for the detection of superoxide anions released by HepG2 cells.