In this study, a new strategy for the selection of aptamers against small-molecule target was established using gold nanoparticles (AuNPs) as the separation matrix and Zinc(II)-Protoporphyrin IX (ZnPPIX) as the target molecule without the immobilization step due to the absorption of ssDNA on AuNPs. The progress of the selection process was monitored by the recovery rate and the fluorescence enhancement of N-methyl mesoporphyrin IX (NMM) after reacting with each selected pool. After 11 rounds of selection, a truncated aptamer ZnP1.2 with a low-micromolar dissociation constant was obtained, and it also showed good fluorescence enhancement for NMM and the enhanced peroxidase activity after binding with hemin, indicating this functional aptamer has potential to be a light-up fluorescent probe and a DNAzyme which could be used as an alternative to peroxidases for many colorimetric or chemiluminescent detections in biosensing events. The experimental results show that the simple and convenient AuNP-based SELEX is very conducive to the selection of aptamers for small-molecule targets.

中文翻译：

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基于金纳米粒子的SELEX的小分子卟啉DNA适体的体外选择。

在这项研究中，建立了一种针对小分子靶标的适体选择的新策略，该方法使用金纳米颗粒（AuNPs）作为分离基质，并以锌（II）-原卟啉IX（ZnPPIX）作为靶分子，无需固定步骤，因为ssDNA在AuNPs上的吸收。与每个选定的池反应后，通过N-甲基中卟啉IX（NMM）的回收率和荧光增强来监测选择过程的进展。经过11轮选择，获得了具有低微摩尔解离常数的截短适体ZnP1.2，并且还显示了NMM良好的荧光增强以及与血红素结合后过氧化物酶活性的增强，这表明该功能性适体可能是发光的荧光探针和脱氧核糖核酸酶，可被用作生物传感事件中许多比色或化学发光检测的过氧化物酶的替代物。实验结果表明，基于AuNP的SELEX简单方便，非常有利于小分子靶标适体的选择。