基于无标记金纳米簇的新型荧光生物传感器在赭曲霉毒素A快速检测中的应用

基于快速合成无标记核酸适配体（aptamer，Apt）模板金纳米簇（gold nanocluster，AuNCs），并以核酸Apt部分互补的单链DNA修饰的金纳米颗粒（gold nanoparticles，AuNPs）结合，构建新型荧光复合纳米生物传感器。利用检测靶标与核酸Apt之间更强结合力，使已荧光猝灭的Apt-AuNCs@cDNA-AuNPs复合纳米传感器发生荧光共振能量转移，最终体系荧光强度值恢复的特性，用于快速准确检测赭曲霉毒素A（ochratoxin A，OTA）。结果表明，OTA质量浓度在0.01～2.5 ng/mL之间，荧光强度对应峰值（FI）与OTA质量浓度（C）呈现良好的线性关系，回归方程分别为FI=689.84lgC（OTA）＋8 315.31；检出限为0.025 ng/mL（信噪比为3）。该荧光生物传感器具有合成及操作简单、灵敏度高、选择性强、稳定性好及检测下限低的特点，预期在食品中相关有害因子的安全检测等提供一种新的思路和平台。

Application of a Novel Fluorescent Biosensor Based on Unlabeled Gold Nanoclusters in Rapid Detection of Ochratoxin A

In this study,gold nanoclusters templated with unlabeled nucleic acid aptamers were rapidly synthesized for use in combination with gold nanoparticles modified with single-stranded DNA that is partially complementary to the DNA strands of the aptamer in a novel fluorescent composite nano-biosensor for rapid detection of ochratoxin A.The stronger binding force between the target and aptamer brought about fluorescence resonance energy transfer in the Apt-AuNCs@cDNAAuNPs sensor whose fluorescence had been quenched and consequently recovery of the lost fluorescence intensity,thereby allowing the rapid and accurate detection of ochratoxin A(OTA).The results showed that the peak value of fluorescence intensity(FI)displayed a good linear relationship with the concentration(C)of ochratoxin A within the range from 0.01 to 2.5 ng/mL,which was fitted as FI=689.84lgC+8315.31,with the limit of detection(LOD)of 0.025 ng/mL at signal-tonoise ratio of 3.This new fluorescent composite biosensor has the characteristics of simple synthesis,easy operation,high sensitivity,strong selectivity,good stability and a low LOD,which is expected to provide a new idea and platform for the detection of food safety hazard factors.