CuBi bimetallic aerogel as peroxidase-like nanozyme for total antioxidant capacity colorimetric detection

Metal aerogel with porous structure and interlocking pore channel can provide abundant active sites to boost the peroxidase (POD)-like activity for high-performance colorimetric analysis of food quality. Herein, CuBi bimetallic aerogels with different atomic ratio (Cu1Bi9, Cu5Bi5 and Cu9Bi1) were fabricated by a facile one-step reduction strategy, and the POD-like activity of the synthesized CuBi bimetallic aerogels was studied. The specific activity of Cu9Bi1 aerogel was significantly enhanced due to the Bi-doping strategy. Through comparing the Km values we find that CuBi bimetallic aerogel can be used as a cheap alternative to equivalent noble metal materials for biosensor applications. Then, the optimized nanozyme was exploited to establish a colorimetric method for the total antioxidant capacity (TAC) by utilizing ascorbic acid (AA) as a representative antioxidant model. The linear range and limit of detection (LOD) were determined to be 300–900 μM and 59.4 μM, respectively, the wide detection range simplifies sample pre-treatment steps. Additionally, the method also demonstrated good feasibility for the TAC of food samples. The current study expands new fields for the application of metal aerogels and successfully developed macroscopic nanozymes with a convenient application, facile preparation and low cost.