College of Food Science and Engineering, Yangzhou University, Yangzhou, Jiangsu 225127, China.
South Asia Branch of National Engineering Research Center of Dairy Health for Maternal and Child Health, Guilin University of Technology, Guilin 541004, China.
Talanta. 2023 Nov 1;264:124746. doi: 10.1016/j.talanta.2023.124746. Epub 2023 May 27.
In this paper, the potassium cobalt hexacyanoferrate (II), KCoFe(CN), with peroxidase-like activity was used for the fabrication of a novel label-free Lactobacillus rhamnosus GG (LGG) electrochemical immunosensor. The KCoFe(CN) nanocubes were made by a simple hydrothermal method and followed by low-temperature calcination. In addition to structural characterization, the peroxidase-mimicking catalytic property of the material was confirmed by a chromogenic reaction. It is known that HO can oxidize electroactive thionine molecules under the catalysis of horseradish peroxidase (HRP). In this nanozyme-based electrochemical immunoassay, due to the steric hindrance, the formation of immune-complex of LGG and LGG antibody on the modified GCE inhibits the catalytic activity of the peroxidase mimics of KCoFe(CN) and thus reduced the current signal. Therefore, the developed electrochemical immunosensor achieved quantitative detection of LGG. Under optimal conditions, the linear range of the sensor was obtained from 10 to 10 CFU mL with a minimum detection limit (LOD) of 12 CFU mL. Furthermore, the immunosensor was successfully applied in the quantitative detection of LGG in dairy product samples with recoveries ranging from 93.2% to 106.8%. This protocol presents a novel immunoassay method, which provides an alternative implementation pathway for the quantitative detection of microorganisms.
本文使用具有过氧化物酶样活性的六氰合钴酸亚铁钾（KCoFe(CN)）来制备新型无标记鼠李糖乳杆菌 GG（LGG）电化学免疫传感器。KCoFe(CN)纳米立方体通过简单的水热法制备，然后进行低温煅烧。除了结构表征外，还通过显色反应证实了该材料的过氧化物酶模拟催化性能。众所周知，HO 在辣根过氧化物酶（HRP）的催化下可以氧化电活性的噻嗪分子。在这种基于纳米酶的电化学免疫分析中，由于空间位阻，LGG 和 LGG 抗体的免疫复合物在修饰的 GCE 上的形成抑制了 KCoFe(CN)的过氧化物酶模拟物的催化活性，从而降低了电流信号。因此，开发的电化学免疫传感器实现了对 LGG 的定量检测。在最佳条件下，传感器的线性范围为 10 至 10 CFU mL，检测限（LOD）为 12 CFU mL。此外，该免疫传感器成功应用于乳制品样品中 LGG 的定量检测，回收率范围为 93.2%至 106.8%。该方案提出了一种新的免疫分析方法，为微生物的定量检测提供了一种替代的实现途径。
