MOE Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Institute of Nanomedicine and Nanobiosensing, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
MOE Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Institute of Nanomedicine and Nanobiosensing, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
Biosens Bioelectron. 2015 Aug 15;70:268-74. doi: 10.1016/j.bios.2015.03.067. Epub 2015 Mar 26.
Determination of ochratoxin A (OTA) is highly important for food safety control. In this study, a signal-on electrochemiluminescence (ECL) biosensor which combined the characteristics of high efficiency of hyperbranched rolling circle amplification (HRCA) and high selectivity of aptamer was developed for OTA determination. The capture probe DNA (CDNA) was firstly immobilized on the gold electrode surface through Au-S interaction, then the OTA aptamer was modified on the electrode surface through hybridization with CDNA. Since OTA can competitively bind with the aptamer due to their high affinity, which would induce the releasing of aptamer from the electrode surface. Subsequently, the free CDNA on the electrode surface can hybridize with the padlock probe and induce HRCA reaction subsequently. Thus, the HRCA products which contained large amount of double-stranded DNA (dsDNA) fragments can be accumulated on the electrode surface. Since Ru(phen)3(2+) can intercalate into the groove of dsDNA and acts as ECL indicator, high ECL intensity can be detected from the electrode surface. The enhanced ECL intensity has a linear relationship with OTA in the range of 0.05-500 pg/mL with a correlation coefficient of 0.9957, and the limit of detection (LOD) was 0.02 pg/mL. The developed biosensor has been applied to determine OTA concentration in the corn samples with satisfied results.
测定赭曲霉毒素 A（OTA）对于食品安全控制非常重要。在本研究中，结合了超支化滚环扩增（HRCA）高效率和适体高选择性特点的信号开启电化学发光（ECL）生物传感器被开发用于 OTA 的测定。捕获探针 DNA（cDNA）首先通过 Au-S 相互作用固定在金电极表面，然后通过与 cDNA 杂交将 OTA 适体修饰在电极表面上。由于 OTA 由于其高亲和力可以与适体竞争结合，这会诱导适体从电极表面释放。随后，电极表面上的游离 cDNA 可以与发夹探针杂交并随后诱导 HRCA 反应。因此，可以在电极表面上积累包含大量双链 DNA（dsDNA）片段的 HRCA 产物。由于 Ru(phen)3(2+)可以嵌入 dsDNA 的沟槽中并作为 ECL 指示剂，因此可以从电极表面检测到高的 ECL 强度。增强的 ECL 强度与 0.05-500 pg/mL 范围内的 OTA 呈线性关系，相关系数为 0.9957，检测限（LOD）为 0.02 pg/mL。该生物传感器已应用于玉米样品中 OTA 浓度的测定，结果令人满意。
