School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, People's Republic of China.
Anal Sci. 2022 Aug;38(8):1073-1081. doi: 10.1007/s44211-022-00136-0. Epub 2022 Jun 7.
Oxytetracycline-capped gold nanoparticles (OTC-Au NPs) were prepared using sodium borohydride as the reductant and OTC as the capping agent, respectively. The prepared OTC-Au NPs with a size of 6 nm have a maximum surface plasma resonance (SPR) absorption located at 514 nm. The OTC on the surface of Au NPs still can coordinate with Eu ions. Due to the property that OTC has multivalent binding sites with Eu ions, Eu ions can induce the aggregation of OTC-Au NPs. Based on the Eu ions-aggregated OTC-Au NPs, a simple aptamer-free colorimetric sensing method for TCs was developed. Briefly, free TCs compete with OTC on the surface of Au NPs resulting in the change of OTC-Au NPs from an aggregation state to a dispersed state. The whole process takes only 5 min, and as low as 20 nM OTC, 14 nM tetracycline (TC), and 20 nM doxycycline (DC) could be sensitively detected, respectively. The proposed method was also featured as good repeatability and specificity, and was applied to the detection of OTC in lake water with satisfactory recovery.
金纳米粒子（Au NPs）的表面等离子体共振（SPR）吸收峰位于 514nm。金纳米粒子表面的 OTC 仍然可以与 Eu 离子配位。由于 OTC 与 Eu 离子具有多价结合位点的特性，Eu 离子可以诱导 OTC-Au NPs 的聚集。基于 Eu 离子聚集的 OTC-Au NPs，建立了一种简单的无适体比色法检测 TCs 的方法。简要地说，游离的 TCs 与 Au NPs 表面的 OTC 竞争，导致 OTC-Au NPs 从聚集状态变为分散状态。整个过程只需 5 分钟，对 OTC、TC 和 DC 的检测限分别低至 20 nM、14 nM 和 20 nM。该方法还具有良好的重现性和特异性，并成功应用于湖水样品中 OTC 的检测，回收率令人满意。
