基于脱氧核酶和纳米探针双重信号放大的电致化学发光超敏传感器现场检测中药真菌毒素研究

Traditional Chinese medicines (TCMs) are prone to be contaminated by multiple mycotoxins in the processes of storage and circulation, affecting the quality and safety of them. High-efficiency and low-cost methods for on-site rapid detection of multi-mycotoxins in TCMs have become the urgent requirement of the TCM research fields and related supervision departments. Electrochemiluminescence (ECL) sensor based on the specific identification of aptamer and effective labeling of nanocrystals (NCs) can achieve simultaneous, real-time and quick detection of multiple targets in a small amount of sample, which has the advantages of high sensitivity, low cost and good controllability. With the introduction of deoxyribozyme and gold nanopartides (GNPs), the ECL signal of the sensor can be effectively amplified. In the present project, based on the previously established evaluation technique for aptamer, with the mycotoxins of high toxicity and incidence in TCMs as the focused objects, we aim to firstly screen mycotoxin aptamers for specific identification targets in TCMs through the modified capillary electrophoresis-systematic evolution of ligands by exponential enrichment (CE-SELEX) technique, and then to screen deoxyribozyme by the PCR-based catalytic elution method, and further to prepare high-performance GNPs by sodium citrate reduction method, as well as core-shell NCs by water phase method using thioglycolic acid for synthesizing GNPs-NCs composite nano-probes. Together with the removable and portable ECL detection instrument and multidisciplinary techniques, we attempt to establish a novel ultra-sensitive ECL sensor detection method based on the dual signal amplification strategy of deoxyribozyme and the nano-probes for on-site high-throughput analysis of multi-mycotoxins in TCMs. At the same time, the results of on-site analysis using the novel established ECL sensing method and indoor detection using UPLC-MS/MS were systematically compared by multivariate statistical analysis techniques to confirm the accuracy and universality of the developed method in more TCMs. Our study will provide valuable references and supports for on-site, real-time and rapid high-throughput detection of multiple mycotoxins in TCMs. In summary, this project has important theoretical and practical significance for eliminating potential safety risks of mycotoxins in TCMs, and for breaking foreign trade barriers, further for increasing the export amounts of more TCMs to more countries.

中药材在储藏和流通过程中易污染多种真菌毒素，高效低成本的现场检测已成为中药安全研究领域和监管部门的迫切需求。基于适体特异识别和纳米晶标记的电致化学发光(ECL)传感器仅需少量样品即可实现多目标成分实时快速检测。借助脱氧核酶和金纳米可高效放大ECL信号。本项目拟在前期建立的适体评价技术基础上，重点针对毒性大、残留率高的真菌毒素，筛选适合中药检测的适体和脱氧核酶，制备具有优良ECL效率的纳米晶，结合优化的高性能金纳米合成“金纳米-纳米晶”探针，配以便携式电致化学发光检测仪，建立基于脱氧核酶和纳米探针双重信号放大的中药真菌毒素现场电致化学发光超敏传感器检测新方法。同时佐以UPLC-MS/MS实验室检测结果，确证新方法在中药材上的准确性和普适性，为中药真菌毒素的现场检测提供技术支撑。该项目实施对消除中药真菌毒素的潜在安全隐患、突破国外贸易壁垒、增加我国中药材出口创汇，具有重要的理论价值和现实意义。

真菌毒素是产毒真菌产生的次级代谢产物，具有较强的肝肾毒性及致癌、致畸、致突变等作用，可污染食品、饲料及中药材等基质，严重影响其质量和安全性、有效性。因此，建立快速、灵敏、准确的真菌毒素（如黄曲霉毒素和赭曲霉毒素等）检测方法尤其现场检测手段极为重要。真菌毒素抗体/适配体可实现对靶标毒素的特异性识别，实现高选择性捕获。电化学免疫传感器和电致化学发光免疫/适配体传感器是将电化学及电致化学发光方法与抗体/适配体识别技术相结合的分析手段，具有响应速度快、灵敏度高、操作简单、成本低等优点。试纸条具有制备过程简单、易操作、可实现现场检测的目的。基于此，本研究分别建立了：（1）麦芽中赭曲霉毒素A（OTA）灵敏快速检测的电化学免疫传感器技术；（2）莲子中黄曲霉毒素B1（AFB1）灵敏检测的ZnCdS@ZnS量子点/纳米晶（QDs）-免标记型电致化学发光传感器技术；（3）百合中OTA特异性检测的量子点-电致化学发光适配体传感器技术；（4）莲子中AFB1现场快速检测的CdSSe@ZnS量子点荧光微球（QBs）免疫层析试纸条传感器；（5）莲子中多种真菌毒素同时快速检测的超高效液相色谱串联质谱法（UFLC-MS/MS）。结果表明，本项目所构建的传感器和试纸条技术及UFLC-MS/MS在稳定性、特异性、重复性方面表现优异，在实际样品检测中表现出良好的性能，可满足麦芽、莲子和百合等不同种类中药材中AFB1和OTA等痕量真菌毒素的实验室和现场检测的需求，在中药材、食品等领域的安全性评估和质量监测等方面具有很大的应用潜力。此外，UFLC-MS/MS方法可确证所建立传感器和试纸条新技术的准确性和可靠性，促进其普及和推广应用。