Majdinasab Marjan, Azziz Aicha, Klös Gunnar, Cortajarena Aitziber L, Edely Mathieu, de la Chapelle Marc Lamy
Department of Food Science and Technology, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran; IMMM - UMR 6283 CNRS, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans, Cedex 9, France.
IMMM - UMR 6283 CNRS, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans, Cedex 9, France.
Spectrochim Acta A Mol Biomol Spectrosc. 2025 Dec 15;343:126511. doi: 10.1016/j.saa.2025.126511. Epub 2025 Jun 1.
Aptamers are single-stranded DNA or RNA oligonucleotides with a unique secondary structure. Target binding induces conformational changes in the secondary structure. Conformation-induced changes in some characteristic Raman bands of DNA aptamer, upon binding to aflatoxin B1 (AFB1), were probed using surface enhanced Raman spectroscopy (SERS). The self-assembled monolayers of thiol-linked DNA aptamer on gold nanoparticles (AuNPs) surface provided a direct, label-free detection method through three adenine bases close to the surface of an AuNPs SERS substrate. The spectra of the DNA aptamer were dominated by the adenine ring breathing mode at 734 cm. Upon binding to AFB1 and conformational changes of the aptamer, the 5'-end of the aptamer with three adenine bases moved away from the surface of AuNPs, resulting in the decreased Raman intensity of the adenine band at 734 cm (I). In addition to the adenine band, the deoxyribose phosphate backbone (O-P-O) band at 1004 cm (I) was decreased after aptamer binding to AFB1. The change of I, corresponding to the AFB1 concentration, was employed for quantitative measurement of AFB1 in the range of 0.1-5000 pg mL. The aptamer-based SERS assay exhibited high sensitivity with a limit of detection (LOD) of 0.24 pg mL for I calibration curve.
适配体是具有独特二级结构的单链DNA或RNA寡核苷酸。与靶标结合会诱导二级结构发生构象变化。利用表面增强拉曼光谱（SERS）探究了DNA适配体与黄曲霉毒素B1（AFB1）结合时，其某些特征拉曼谱带因构象变化而产生的改变。硫醇连接的DNA适配体在金纳米颗粒（AuNPs）表面自组装形成的单分子层，通过靠近AuNPs SERS基底表面的三个腺嘌呤碱基提供了一种直接的、无需标记的检测方法。DNA适配体的光谱以734 cm处的腺嘌呤环呼吸模式为主。与AFB1结合且适配体发生构象变化后，带有三个腺嘌呤碱基的适配体5'端远离AuNPs表面，导致734 cm处腺嘌呤谱带的拉曼强度（I）降低。除了腺嘌呤谱带外，适配体与AFB1结合后，1004 cm处的脱氧核糖磷酸骨架（O-P-O）谱带（I）也降低。将与AFB1浓度对应的I的变化用于定量测定0.1 - 5000 pg mL范围内的AFB1。基于适配体的SERS检测方法表现出高灵敏度，I校准曲线的检测限（LOD）为0.24 pg mL。
