Department of Physical and Chemical Inspection, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250000, China.
Institute of Quality Standard and Testing Technology for Agro-Products, Shandong Academy of Agricultural Sciences, Jinan 250100, China.
Molecules. 2024 Jun 25;29(13):3013. doi: 10.3390/molecules29133013.
In this study, a self-responsive fluorescence aptasensor was established for the determination of lactoferrin (Lf) in dairy products. Herein, the aptamer itself functions as both a recognition element that specifically binds to Lf and a fluorescent signal reporter in conjunction with fluorescent moiety. In the presence of Lf, the aptamer preferentially binds to Lf due to its specific and high-affinity recognition by folding into a self-assembled and three-dimensional spatial structure. Meanwhile, its reduced spatial distance in the aptamer-Lf complex induces a FRET phenomenon based on the quenching of 6-FAM by amino acids in the Lf protein, resulting in a turn-off of the fluorescence of the system. As a result, the Lf concentration can be determined straightforwardly corresponding to the change in the self-responsive fluorescence signal. Under the optimized conditions, good linearities (R > 0.99) were achieved in an Lf concentration range of 2~10 μg/mL for both standard solutions and the spiked matrix, as well as with the desirable detection limits of 0.68 μg/mL and 0.46 μg/mL, respectively. Moreover, the fluorescence aptasensor exhibited reliable recoveries (89.5-104.3%) in terms of detecting Lf in three commercial samples, which is comparable to the accuracy of the HPCE method. The fluorescence aptasensor offers a user-friendly, cost-efficient, and promising sensor platform for point-of-need detection.
在这项研究中，建立了一种自响应荧光适体传感器，用于测定乳制品中的乳铁蛋白（Lf）。在此，适体本身既可以作为与荧光部分结合的特定结合 Lf 的识别元件，也可以作为荧光信号报告器。在 Lf 的存在下，由于适体通过折叠成自组装的三维空间结构与 Lf 特异性和高亲和力地结合，因此优先与 Lf 结合。同时，适体-Lf 复合物中其空间距离的减小会导致基于 Lf 蛋白中氨基酸对 6-FAM 的猝灭的 FRET 现象，从而导致系统的荧光关闭。因此，Lf 浓度可以直接根据自响应荧光信号的变化来确定。在优化条件下，标准溶液和加标基质的 Lf 浓度范围为 2~10μg/mL 时，均具有良好的线性关系（R > 0.99），检测限分别为 0.68μg/mL 和 0.46μg/mL。此外，该荧光适体传感器在三种商业样品中检测 Lf 时具有可靠的回收率（89.5-104.3%），与 HPCE 方法的准确性相当。该荧光适体传感器为现场检测提供了一种用户友好、经济高效且有前途的传感器平台。
