A fluorescent assay for total antioxidant capacity (TAC) detection based on the light-responsive oxidase-like activity of bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs) has been developed. Thiamine (TH) as the peroxidase substrate usually works at alkaline conditions and thus limits its practical applications. Here, by utilization the light-responsive oxidase-like activity of BSA-AuNCs, TH is oxidized to fluorescent thiochrome under neutral condition in two minutes due to the single oxygen generated by BSA-AuNCs upon light irradiation. After the introduction of antioxidants into the BSA-AuNCs-TH system, the formation of thiochrome is inhibited resulting in the fluorescence decrease. On the basis of the above facts, BSA-AuNCs-TH-based assay has been fabricated and applied successfully to detect antioxidants and the TAC of vitamin C tablets as well as some commercial fruit juice with satisfied results. This work may provide novel insights into developing light-responsive nanozymes-based fluorescent assays.

已经开发了一种基于牛血清白蛋白稳定的金纳米团簇（BSA-AuNCs）的光响应氧化酶样活性的总抗氧化剂容量（TAC）检测的荧光测定法。硫胺素（TH）作为过氧化物酶的底物通常在碱性条件下工作，因此限制了其实际应用。在此，通过利用BSA-AuNCs的光响应性氧化酶样活性，由于BSA-AuNCs在光照射时产生的单氧，TH在中性条件下在两分钟内被氧化成荧光硫色素。将抗氧化剂引入BSA-AuNCs-TH系统后，抑制了巯基色素的形成，导致荧光减弱。基于以上事实，已建立了基于BSA-AuNCs-TH的检测方法，并将其成功地检测出维生素C片剂以及一些商用果汁中的抗氧化剂和TAC，结果令人满意。这项工作可能会为开发基于光响应纳米酶的荧光测定提供新颖的见解。