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 CeO 2  (Arg-CeO 2 ) 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-CeO 2  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-CeO 2  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. sichuanens e within 40 min. The proposed visual assessment platform presented exhibits promising application prospects in the field of TAC assessment in food. Graphical