College of Life Science, Chongqing Normal University, Chongqing, 401331, PR China.
Bioassay 3D Reconstruction Laboratory, Chongqing College of Electronic Engineering, Chongqing, 401331, PR China.
Anal Chim Acta. 2023 Apr 29;1252:341044. doi: 10.1016/j.aca.2023.341044. Epub 2023 Mar 8.
Nitrofurazone (NFZ) is an antibiotic banned in many countries, as its residue seriously harms the human body. Herein, anti-NFZ aptamers were selected and identified based on the magnetic bead SELEX technique using a ssDNA library with a full length of 90 nucleotides (nt). Five full sequence candidate aptamers (NFZ8, NFZ24, NFZ28, NFZ34, and NFZ70) were obtained by secondary structure analysis. We optimized the entire sequence to obtain a truncated aptamer, a 16 nt sequence (NFZ8-1:5'-GTTCTATTGAAAAAAC-3') that showed the highest affinity for NFZ (K = 76.11 nM). The binding site of NFZ and aptamer NFZ8-1 was found to be "GAA" by molecular docking. In addition, utilizing the most special truncated aptamer NFZ8-1 as the identification probe, a graphene oxide fluorescent aptasensor is an innovative for the detection of NFZ residue that showed a wide linear reach from 1.25 to 160 ng/mL and a low limit of detection of 1.13 ng/mL. In the actual water environment sample detection, the recovery rate ranged from 95.21 to 113.66%, and the coefficient of variation ranged from 3.53 to 11.24%. These results demonstrate that the NFZ-truncated aptamer applied to the aptasensor provides a novel methodology for recognizing NFZ residues.
硝呋太尔（NFZ）是一种在许多国家被禁用的抗生素，因为其残留会严重危害人体健康。本研究采用磁珠 SELEX 技术，以全长为 90 个核苷酸（nt）的 ssDNA 文库为基础，筛选并鉴定了抗 NFZ 的适体。通过二级结构分析，获得了 5 条全长候选适体（NFZ8、NFZ24、NFZ28、NFZ34 和 NFZ70）。我们对整个序列进行了优化，得到了一个截断的适体，一个 16 个核苷酸序列（NFZ8-1：5'-GTTCTATTGAAAAAAC-3'），对 NFZ 表现出最高的亲和力（K=76.11 nM）。通过分子对接发现，NFZ 与适体 NFZ8-1 的结合位点为“GAA”。此外，利用最特殊的截断适体 NFZ8-1 作为识别探针，构建了一种基于石墨烯氧化物荧光适体传感器的新型 NFZ 残留检测方法，其线性范围从 1.25 到 160 ng/mL，检测限低至 1.13 ng/mL。在实际水环境样品检测中，回收率范围为 95.21%至 113.66%，变异系数范围为 3.53%至 11.24%。这些结果表明，应用于适体传感器的 NFZ 截断适体为识别 NFZ 残留提供了一种新方法。
