Nanozymes, as ideal alternatives to natural enzymes, have great prospects in the biosensor field due to their remarkable catalytic activity, gratifying stability, and low cost. Herein, a new oxidase-like nanozyme with Fe-doped hollow carbon spheres (Fe/HCS) was prepared. Abundant active oxygen species (¹O₂) are generated by the interaction of the Fe/HCS with dissolved oxygen. Then, colorless 3,3′,5,5′-tetramethylbenzidine (TMB) is oxidized to blue oxidized TMB (oxTMB), while glutathione (GSH) can reduce oxTMB, resulting in fading of the blue color. In addition, glutathione S-transferase (GST) catalyzes the conjugation reaction between GSH and 1-chloro-2,4-dinitrobenzene (CDNB) to form an adduct, which decreases the reducibility of GSH. Therefore, a direct and sensitive colorimetric method for the detection of the glutathione S-transferase activity was established, which exhibited a linear detection range of 0.001–0.02 U·L⁻¹ and an ultralow detection limit of 0.565 mU·L⁻¹. This colorimetric method was successfully applied to the detection of glutathione S-transferase in human serum samples, providing a new route for the application of nanozymes in biosensing techniques.

纳米酶作为天然酶的理想替代品，由于其卓越的催化活性，令人满意的稳定性和低成本，在生物传感器领域具有广阔的前景。本文中，制备了一种新的具有铁掺杂空心碳球（Fe / HCS）的氧化酶样纳米酶。丰富的活性氧（¹ O ₂）是由Fe / HCS与溶解氧的相互作用产生的。然后，将无色的3,3'，5,5'-四甲基联苯胺（TMB）氧化为蓝色氧化的TMB（oxTMB），而谷胱甘肽（GSH）可以还原oxTMB，导致蓝色褪色。另外，谷胱甘肽S-转移酶（GST）催化GSH与1-氯-2，4-二硝基苯（CDNB）之间的结合反应形成加合物，这降低了GSH的还原性。因此，建立了直接灵敏的比色法检测谷胱甘肽S-转移酶活性的方法，其线性检测范围为0.001–0.02 U·L ^-1，超低检测限为0.565 mU·L ^-1。该比色法已成功应用于人类血清样品中谷胱甘肽S-转移酶的检测，为纳米酶在生物传感技术中的应用提供了新途径。