College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan, 250014, People's Republic of China.
Mikrochim Acta. 2019 Jun 11;186(7):430. doi: 10.1007/s00604-019-3566-7.
A photoelectrochemical (PEC) method is described for aptamer-based detection of ofloxacin (OFL). It is making use of a TiO nanotube array (NTA) that is sensitized with a structure composed of polydopamine and silver sulfide nanoparticles. The NTA were prepared by a two-step synthetic method. First, the TiO nanotube electrode was covered with AgS nanoparticles via successive ionic layer adsorption and reaction strategy. Next, they were coated with a thin film of polydopamine (PDA) by in-situ polymerization. The inorganic/organic nanocomposites exhibit distinctly enhanced visible-light PEC activity. This was exploited to fabricate a PEC aptasensor. The PDA film serves as both the sensitizer for charge separation and as a support to bind the aptamer against OFL. The aptasensor undergoes a decrease in photocurrent due to the formation of the aptamer-OFL complex. Under the optimized conditions and at a typical working potential of 0 V (vs. Hg/HgCl), the NTA has a linear response in the 5.0 pM to 100 nM OFL concentration range and a 0.75 pM detection limit (at S/N = 3). The aptasensor was successfully applied to the determination of OFL in spiked milk samples. Graphical abstract Schematic illustration for the preparation and mechanism of the photoelectrochemical aptasensor for ofloxacin. TiO NTs: TiO nanotube arrays; PDA: polydopamine; MCH: 6-mercapto-1-hexanol; OFL: ofloxacin; PEC: photoelectrochemistry; CB: conduction band; VB: valence band; LUMO: the lowest unoccupied molecular orbital; HOMO: the highest occupied molecular orbital; AA: ascorbic acid.
一种基于光电化学（PEC）的适体法被用来检测氧氟沙星（OFL）。它是利用经聚多巴胺和硫化银纳米粒子结构敏化的 TiO 纳米管阵列（NTA）来实现的。NTA 是通过两步合成方法制备的。首先，通过离子层吸附和反应策略，在 TiO 纳米管电极上覆盖 AgS 纳米粒子。接下来，通过原位聚合在其上涂覆一层薄的聚多巴胺（PDA）膜。这种无机/有机纳米复合材料表现出明显增强的可见光 PEC 活性。这被用来制造 PEC 适体传感器。PDA 膜不仅可以作为电荷分离的敏化剂，还可以作为结合针对 OFL 的适体的支撑物。由于形成了适体-OFL 复合物，适体传感器的光电流会降低。在优化条件下，在典型的工作电位 0 V（相对于 Hg/HgCl）下，NTA 在 5.0 pM 至 100 nM OFL 浓度范围内呈线性响应，检测限为 0.75 pM（在 S/N = 3 时）。该适体传感器成功应用于加标牛奶样品中 OFL 的测定。
