Biomineralized Mn3(PO4)2/aptamer nanosheets for enhanced electrochemical determination of C-reactive protein

Abstract Bio-inspired enzyme–inorganic hybrid nanomaterials are extensively employed for biological applications owing to their capability of enhancing enzyme activity and stability compared with free counterpart. They play a vital role in signal output and amplification during bioassay, but usually suffer from deactivation and costing problems, which motivates us to seek a more robust signal generation pattern. The coordination interaction between metal ions and amide groups in enzyme drives the evolution of various morphology and structure. Inspired by this, C-reactive protein (CRP) aptamer, with amide groups in their nucleobases, is introduced as an organic part serving as a linker and biorecognition unit to prepare aptamer-inorganic hybrid nanosheets, and be applied for CRP detection. Unlike using organic enzymes as a signal enhancer, the inorganic part, Mn3(PO4)2, is exploited for generating and transducing firm current signals, which stem from electrochemical active molybdophosphate precipitates reacted by phosphate and external molybdate. This enzyme-free electrochemical aptasensor based on biomineralized Mn3(PO4)2/aptamer exhibits an excellent detection performance for CRP. And the reliability is also acceptable compared to the traditional immunoturbidimetric method at the hospital, suggesting our method good feasibility for clinical diagnosis.