Manganese Phosphate Self-assembled Nanoparticle Surface and Its application for Superoxide Anion Detection

Quantitative analysis of superoxide anion (O 2 ·− ) has increasing importance considering its potential damages to organism. Herein, a novel Mn-superoxide dismutase (MnSOD) mimics, silica-manganous phosphate (SiO 2 -Mn 3 (PO 4 ) 2 ) nanoparticles, were designed and synthesized by surface self-assembly processes that occur on the surface of silica-phytic acid (SiO 2 -PA) nanoparticles. The composite nanoparticles were characterized by fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), electron diffraction pattern, energy dispersive spectroscopy (EDS) and elemental mapping. Then the electrochemical measurements of O 2 ·− based on the incorporation of SiO 2 -Mn 3 (PO 4 ) 2 onto the surface of electrodes were performed and some satisfactory results were obtained. This is the first report that manganous phosphate (Mn 3 (PO 4 ) 2 ) nanoparticles with shape-controlled, but not multilayer sheets, were utilized for O 2 ·− detection. The surface self-assembly technology we proposed will offer the ideal material to construct more types biosensor and catalytic system for its nanosized effect.