School of Chemistry, Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, South China Normal University, Guangzhou, 510006, People's Republic of China.
Mikrochim Acta. 2021 Feb 4;188(3):65. doi: 10.1007/s00604-021-04702-7.
A nanozyme based on CoFeO modified with MoS was constructed for colorimetric determination of cysteine (Cys) and glutathione (GSH). Firstly, ferrite CoFeO is synthesized, and it is then modified by MoS to form a flower-like polymer (MoS@CoFeO). In the presence of HO, a redox interaction takes place, and the resulting hydroxyl promoted a colorimetric conversion from colorless to blue in the presence of 3,3',5,5'-tetramethylbenzidine (TMB). However, once Cys or GSH is added, they are capable to compete with the interaction of the hydroxyl with TMB, resulting in an inhibition of the colorimetric conversion. The colorimetric distinction is sensitive to the amount of target. The results obtained proved that the catalytic efficiency of MoS@CoFeO is 4.4-fold and 1.8-fold to that of MoS and CoFeO. Meanwhile, the K values to TMB and HO are 0.067 and 0.048 mM, respectively, which are 6.5-fold and 77-fold, respectively smaller than those of natural peroxidase such as HPR. This indicates that the MoS@CoFeO possesses a favorable interaction affinity. Additionally, the colorimetric distinction caused by the competition between TMB and cysteine or glutathione is obvious. The signal responses to cysteine and glutathione are linear in the range 0.515 μM and 0.535 μM, and the LODs are 0.10 and 0.21 μM, respectively. In practical assay of Cys in serum, the RSD of the sample tests is 4.6%, and the recoveries for the spiked assays are 95.3% and 96.0% with the RSD of 2.1% and 4.2%, respectively.
基于 CoFeO 修饰的 MoS 的纳米酶被构建用于半胱氨酸 (Cys) 和谷胱甘肽 (GSH) 的比色测定。首先，合成了铁氧体 CoFeO，然后用 MoS 对其进行修饰，形成花状聚合物 (MoS@CoFeO)。在 HO 的存在下，发生氧化还原相互作用，生成的羟基在 3,3',5,5'-四甲基联苯胺 (TMB) 的存在下促进比色从无色到蓝色的转化。然而，一旦添加 Cys 或 GSH，它们能够与羟基与 TMB 的相互作用竞争，导致比色转化的抑制。比色差异对目标物的量敏感。结果表明，MoS@CoFeO 的催化效率分别是 MoS 和 CoFeO 的 4.4 倍和 1.8 倍。同时，MoS@CoFeO 与 TMB 和 HO 的 K 值分别为 0.067 和 0.048 mM，分别是天然过氧化物酶（如 HPR）的 6.5 倍和 77 倍。这表明 MoS@CoFeO 具有良好的相互作用亲和力。此外，TMB 和半胱氨酸或谷胱甘肽之间竞争引起的比色差异明显。半胱氨酸和谷胱甘肽的信号响应在 0.515 μM 和 0.535 μM 范围内呈线性，LOD 分别为 0.10 和 0.21 μM。在血清中 Cys 的实际测定中，样品测试的 RSD 为 4.6%，对于加标测定，回收率分别为 95.3%和 96.0%，RSD 分别为 2.1%和 4.2%。
