Xu Hongyan, Xiao Chengui, Zhao Fengjuan, Suo Zhiguang, Liu Yong, Wei Min, Jin Baohui
College of Food Science and Technology, Henan Key Laboratory of Cereal and Oil Food Safety and Nutrition, Henan University of Technology, Zhengzhou, 450001, PR China.
Food Inspection and Quarantine Technology Center of Shenzhen Customs, Shenzhen Academy of Inspection and Quarantine, Shenzhen, 518045, PR China.
Anal Chim Acta. 2025 Feb 22;1340:343665. doi: 10.1016/j.aca.2025.343665. Epub 2025 Jan 13.
Ochratoxin A (OTA) is toxic secondary metabolites produced by fungi and can pose a serious threat to food safety and human health. Due to the high stability and toxicity, OTA contamination in agricultural products is of great concern. Therefore, the development of a highly sensitive and reliable OTA detection method is crucial to ensure food safety. Although fluorescent sensors have been widely used for OTA detection, they still face challenges such as false positives and insufficient sensitivity, thus further improvement of the detection performance is necessary.
Herein, a ratiometric biosensor based on DNA-gated Fe₃O₄@Uio-66-NH₂ nanocomposites and Nucleic Acid Exonuclease I (Exo I)-assisted signal amplification was constructed for the sensitive detection of OTA. This functional nanocomposite combines magnetic, porous and fluorescent properties. Fe₃O₄ of the core enables efficient magnetic separation, while the porous structure of Uio-66-NH₂ encapsulates the fluorescent dye rhodamine 6G (Rho 6G). In addition, a label-free DNA gating strategy was introduced to control the release of Rho 6G. The sensor performs OTA detection by the fluorescence signal ratio of FeO@Uio-66-NH and Rho 6G, which effectively avoids false positives of the sensor. Accelerated release of Rho 6G using Exo I greatly improves the sensitivity of the sensor. The sensor has a low LOD (0.308 ng mL) and the recoveries for OTA detection in real samples were 92.4%-116.0 %.
The development of this ratiometric fluorescent aptasensor highlights its potential for highly sensitive OTA detection, offering significant advantages in selectivity and accuracy due to its unique DNA-gated mechanism and the dual fluorescence signal ratio strategy. Additionally, the use of Fe₃O₄@Uio-66-NH₂ enables effective magnetic separation, while the Exo I-assisted signal amplification enhances sensitivity, making this sensor a powerful tool for detecting OTA in complex sample matrices with high reliability.
赭曲霉毒素A（OTA）是真菌产生的有毒次生代谢产物，会对食品安全和人类健康构成严重威胁。由于其高稳定性和毒性，农产品中的OTA污染备受关注。因此，开发一种高度灵敏且可靠的OTA检测方法对于确保食品安全至关重要。尽管荧光传感器已广泛用于OTA检测，但它们仍面临假阳性和灵敏度不足等挑战，因此有必要进一步提高检测性能。
在此，构建了一种基于DNA门控的Fe₃O₄@UiO-66-NH₂纳米复合材料和核酸外切酶I（Exo I）辅助信号放大的比率型生物传感器，用于灵敏检测OTA。这种功能性纳米复合材料兼具磁性、多孔性和荧光特性。核心的Fe₃O₄实现高效磁分离，而UiO-66-NH₂的多孔结构包裹荧光染料罗丹明6G（Rho 6G）。此外，引入了无标记DNA门控策略来控制Rho 6G的释放。该传感器通过FeO@UiO-66-NH和Rho 6G的荧光信号比率进行OTA检测，有效避免了传感器的假阳性。利用Exo I加速Rho 6G的释放极大地提高了传感器的灵敏度。该传感器具有低检测限（0.308 ng mL），实际样品中OTA检测的回收率为92.4%-116.0%。
这种比率型荧光适配体传感器的开发突出了其在高灵敏OTA检测方面的潜力，由于其独特的DNA门控机制和双荧光信号比率策略，在选择性和准确性方面具有显著优势。此外，Fe₃O₄@UiO-66-NH₂的使用实现了有效的磁分离，而Exo I辅助信号放大提高了灵敏度，使该传感器成为在复杂样品基质中高可靠性检测OTA的有力工具。
