Department of Instrumentation and Analytical Chemistry, CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
Mikrochim Acta. 2024 Feb 26;191(3):157. doi: 10.1007/s00604-024-06252-0.
It has been observed that polyvalent metal ions can mediate the adsorption of DNA on polydopamine (PDA) surfaces. Exploiting this, we used two divalent metal ions (Mg or Ca) to promote the adsorption of fluorescence-labelled ochratoxin A (OTA) aptamers on PDA-coated magnetic nanoparticles (FeO@PDA). Based on the different adsorption affinities of free aptamers and OTA-bound aptamers, a facile assay method was established for OTA detection. The aptamers adsorbed on FeO@PDA were removed via simple magnetic separation, and the remaining aptamers in the supernatant exhibited a positive correlation with the OTA concentration. The concentrations of Mg and Ca were finely tuned to attain the optimal adsorption affinity and sensitivity for OTA detection. In addition, other factors, including the FeO@PDA dosage, pH, mixing order, and incubation time, were studied. Finally, under optimized conditions, a detection limit (3σ/s) of 1.26 ng/mL was achieved for OTA. Real samples of spiked red wine were analysed with this aptamer-based method. This is the first report of regulating aptamer adsorption on the PDA surface with polyvalent metal ions for OTA detection. By changing the aptamers, the method can be easily extended to other target analytes.
已经观察到多价金属离子可以介导 DNA 在聚多巴胺（PDA）表面的吸附。利用这一点，我们使用两种二价金属离子（Mg 或 Ca）来促进荧光标记的赭曲霉毒素 A（OTA）适体在 PDA 涂层的磁性纳米颗粒（FeO@PDA）上的吸附。基于游离适体和 OTA 结合适体的不同吸附亲和力，建立了一种用于 OTA 检测的简单测定方法。通过简单的磁分离去除吸附在 FeO@PDA 上的适体，上清液中剩余的适体与 OTA 浓度呈正相关。精细调节 Mg 和 Ca 的浓度以达到最佳的 OTA 检测吸附亲和力和灵敏度。此外，还研究了其他因素，包括 FeO@PDA 剂量、pH 值、混合顺序和孵育时间。最后，在优化条件下，OTA 的检测限（3σ/s）达到 1.26 ng/mL。用这种基于适体的方法分析了加标红酒的实际样品。这是首次报道使用多价金属离子调节 PDA 表面上适体的吸附用于 OTA 检测。通过改变适体，该方法可以很容易地扩展到其他目标分析物。
