Biomimetic cascade nanoreactor with triple-enzyme mimetic activities for colorimetric detection of acid phosphatase

Delighted by the high catalytic efficiency and superior selectivity of multiple enzyme-driven biological catalytic cascades, biomimetic cascade nanoreactors have drawn much attention recently. Here, a new type of biomimetic cascade nanoreactor – Co nanoparticles embedded N-enriched carbon nanocubes (Co,N-CNC) which derived from ZIF-67 nanocubes was designed and utilized for acid phosphatase (ACP) detection. The distinctive composition and cubic structure endowed Co,N-CNC with significantly enhanced triple-enzyme mimetic activities, including oxidase (OXD)-, peroxidase (POD)-, and catalase (CAT)-like activities. Employing the OXD- and POD-like activities of Co,N-CNC nanoreactor, a cascade amplification strategy was proposed for the first time for ACP colorimetric detection without the assistance of destructive H2O2. Based on the high catalytic activity of Co,N-CNC and the cascade amplification strategy, a good linear relationship was obtained from 0.01 to 10.0 mU/mL, with a lower detection limit of 6.1 μU/mL. Significantly, the Co,N-CNC could detect ACP in human serum samples with high accuracy. Therefore, the Co,N-CNC nanoreactor with triple-enzyme mimetic activities displayed broad prospects for biosensing, medical diagnostics and biotechnological research.