Constructing high effective nano-Mn 3 (PO 4 ) 2 -chitosan in situ electrochemical detection interface for superoxide anions released from living cell.

Monitoring superoxide anions in living cells have attracted much academic and biomedical interest due to their important role in metabolic processes. Herein, we confined ultra-small nano-Mn ₃ (PO ₄ ) ₂ in chitosan and designed a unique puffy woven sphere consisted by nanowires. Further constructed an effective in situ detection chip using the as-synthesized nano-Mn ₃ (PO ₄ ) ₂ -chitosan for electrochemical sensing of superoxide anions from murine breast tumor cells (4T1). The excellent biocompatibility of chitosan and large size of the Mn ₃ (PO ₄ ) ₂ -chitosan spheres greatly reduced the damage and toxicity of the detection interface to the living cells, while the ultra-small nano-Mn ₃ (PO ₄ ) ₂ in chitosan could effectively catalyze the superoxide anions released from cells. The nano-Mn ₃ (PO ₄ ) ₂ -chitosan-based sensor exhibited high sensitivity (1.6 μA μM ^-1 ), low detection limit (9.4 nM at S/N = 3) and good selectivity for O ₂ ^•- . After cell culture on the surface of nano-Mn ₃ (PO ₄ ) ₂ -chitosan based electrode. As a miniature analytical and sensing platform, results further suggest that the prepared chip offers a more sensitive detective superoxide anions (O ₂ ^•- ) released from 4T1 cell lines than traditional electron paramagnetic resonance (EPR) analysis.
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