Establishment of a visual assessment platform for total antioxidant capacity of Ganoderma sichuanense based on Arg-CeO₂ hydrogel nanozyme utilizing a self-programmed smartphone app and a self-designed 3D-printed device

A multienzyme-like L-argininemodified CeO₂ (Arg-CeO₂) nanozyme was prepared for accurate total antioxidant capacity (TAC) determination of Ganoderma sichuanense (G. sichuanense). It exhibits oxidase-like and peroxidase-like activities catalyzing the generation of superoxide anion free radicals and hydroxyl radicals, accelerating 3, 3', 5, 5'-tetramethylbenzidine (TMB) chromogenic reaction. Antioxidants can effectively eliminate the generated free radicals, inhibiting the TMB chromogenic reaction. Hence, TAC can be assessed by Arg-CeO₂ catalyzed TMB chromogenic reaction using ascorbic acid (AA) as a reference substance. TAC of G. sichuanense extracted using different solvents was determined, indicating the highest TAC observed in the G. sichuanense extracted by the mixture solvent (deionized water/ethanol/ethyl acetate = 1 : 1 : 1). A visual assessment platform based on Arg-CeO₂ hydrogel nanozyme utilizing a self-programmed smartphone app and a self-designed 3D printed device is established. TAC using AA as a reference substance (3.33 ~ 83.33 µM) can be detected with a detection limit as low as 0.58 µM. The platform can realize one-step quantitative determination of TAC in G. sichuanense within 40 min. The proposed visual assessment platform presented exhibits promising application prospects in the field of TAC assessment in food.