5,10,15,20-tetrakis (4-carboxylphenyl) porphyrin functionalized NiCo₂S₄ yolk-shell nanospheres (Por-NiCo₂S₄) were fabricated by a facile and efficient solvothermal strategy and demonstrated to possess excellent peroxidase-like activity. Compared with pure NiCo₂S₄ nanospheres, Por-NiCo₂S₄ exhibits the superior peroxidase activity, which was evaluated by the fast oxidation of 3,3´,5,5´-tetramethylbenzidine (a chromogenic substrate, TMB) by H₂O₂ to form the blue product (oxTMB) only in 10 s. The systematic studies including radical scavenger, fluorescence probe, and electrochemical experiments confirm that superoxide free radicals (•O₂⁻) play a key role in catalytic reactions, in addition to the synergistic effect of holes (h⁺). Based on the developed peroxidase activity of Por-NiCo₂S₄, and combined with cholesterol oxidase (Chox), a fast cascade reaction sensing platform has been constructed to quantitatively determination cholesterol in a wide linear range of 0.1-9.0 mM with the detection limit of 19.36 μM. The Por-NiCo₂S₄ based colorimetric biosensing platform has been used for determining the levels of total cholesterol in serum samples, indicating Por-NiCo₂S₄ is expected to be used as the promising materials for fast visual colorimetry in clinical medical detection.

5,10,15,20-四（4-羧基苯基）卟啉官能化的NiCo ₂ S ₄卵黄壳纳米球（Por-NiCo ₂ S ₄）是通过一种简便而有效的溶剂热策略制备的，并被证明具有出色的过氧化物酶样活性。 。与纯NiCo ₂ S ₄纳米球相比，Por-NiCo ₂ S ₄表现出优异的过氧化物酶活性，这可以通过H ₂对3,3´，5,5´-四甲基联苯胺（发色底物TMB）的快速氧化来评估Ø ₂仅在10秒钟内形成蓝色产物（oxTMB）。该系统的研究，包括自由基清除剂，荧光探针和电化学实验证实，超氧自由基（•ø ₂ ^- ）起到催化反应中起关键作用，除了孔的协同效应（H ⁺）。基于已开发的Por-NiCo ₂ S ₄过氧化物酶活性，并与胆固醇氧化酶（Chox）结合，构建了快速级联反应传感平台，可在0.1-9.0 mM的宽线性范围内以检测极限定量测定胆固醇为19.36μM。Por-NiCo ₂ S ₄基于比色的生物传感平台已用于确定血清样品中总胆固醇的水平，表明Por-NiCo ₂ S ₄有望用作临床医学检测中快速视觉比色的有前途的材料。