2’-氟取代核酸适配体/氧化石墨烯生物传感器检测预包装食品中金黄色葡萄球菌

Detection of Staphylococcus aureus in prepackaged food by 2’-fluoro-substituted nucleic acid aptamer/graphene oxide biosensor

中文关键词:  2’-氟取代  核酸适配体  氧化石墨烯  生物传感器  金黄色葡萄球菌

英文关键词:2’-fluoro-substituted  nucleic acid aptamer  graphene oxide  biosensor  Staphylococcus aureus

中文摘要:

      目的 开发了一种由2’-氟取代核酸适配体(2’-fluoro-substituted nucleic acid aptamer, 2’F-Apt)和氧化石墨烯(graphene oxide, GO)组成的荧光生物传感器, 实现预包装食品中金黄色葡萄球菌的高灵敏、高特异性检测。方法 该传感器基于2’F-Apt与GO的非共价吸附组装, 依托GO的荧光猝灭效应抑制适配体荧光; 当存在靶标细菌时, 2’F-Apt特异性结合细菌表面蛋白并脱离GO, 荧光信号恢复, 以此实现样品定量检测。结果 相较于未修饰的核酸, 2’-氟取代可减小核酸链构象限制、提升分子柔性, 增加结合位点与比表面积, 强化2’F-Apt与GO的结合作用, 有效抑制非特异性脱落、降低假阳性; 同时可优化靶标识别能力, 提升检测灵敏度。测试结果表明, 2’F-Apt/GO生物传感器对金黄色葡萄球菌的检测线性范围为10~109 CFU/mL, 检出限为5 CFU/mL, 检测性能优异。结论 本研究构建的生物传感器制备方法简便、普适、灵敏度高, 可用于预包装食品中金黄色葡萄球菌的快速检测。

英文摘要:

      Objective To construct a fluorescent biosensor composed of 2’-fluoro-substituted nucleic acid aptamer (2’F-Apt) and graphene oxide (GO) for the highly sensitive and specific detection of Staphylococcus aureus in prepackaged foods. Methods The biosensor was fabricated via non-covalent adsorption and assembly between 2’F-Apt and GO. The fluorescence of the aptamer was quenched by GO. In the presence of target bacteria, 2’F-Apt specifically bound to surface proteins of the bacteria and detached from GO, resulting in the recovery of fluorescence signal, which enabled the quantitative detection of samples. Results Compared with unmodified nucleic acids, 2’-fluoro substitution reduced the conformational constraints of nucleic acid strands and improved molecular flexibility. It also increased binding sites and specific surface area, strengthened the interaction between 2’F-Apt and GO, effectively inhibited non-specific dissociation and reduced false-positive results. Meanwhile, the target recognition capability and detection sensitivity were enhanced. The test results showed that the linear detection range of the 2’F-Apt/GO biosensor for Staphylococcus aureus was 10 to 109 CFU/mL, with a limit of detection of 5 CFU/mL, presenting excellent detection performance. Conclusion The biosensor constructes in this study features simple preparation, good universality and high sensitivity, and can be applied to the rapid detection of Staphylococcus aureus in prepackaged foods.