Babes-Bolyai University, Biomolecular Physics Department, Kogalniceanu 1, RO-400084 Cluj-Napoca, Romania.
Babes-Bolyai University, Biomolecular Physics Department, Kogalniceanu 1, RO-400084 Cluj-Napoca, Romania.
Talanta. 2018 Sep 1;187:47-58. doi: 10.1016/j.talanta.2018.05.006. Epub 2018 May 2.
To detect and recognise three structurally related marine biotoxins responsible for the diarrheic shellfish poisoning (DSP) symptom, namely okadaic acid (OA), dinophysistoxin-1 (DTX-1) and dinophysistoxin-2 (DTX-2) respectively, as well as the structurally different yessotoxin (YTX), we developed a novel surface-enhanced micro-Raman scattering (micro-SERS) approach to investigate for the first time their micro-SERS signalling in solution and jointly analysed them in conjunction with the normal and toxic mussel tissue. YTX provided the main SERS feature surprisingly similar to DTX-1 and DTX-2, suggesting similar molecular adsorption mechanism with respect to the AgNPs. A fingerprint SERS band at 1017 cm characteristic for the C-CH stretching in DTX-1 and DTX-2 and absent in OA SERS signal, allowed direct SERS discrimination of DTX-1,2 from OA. In acid form or as dissolved potassium salt, OA showed reproducible SERS feature for 0.81 μM to 84.6 nM concentrations respectively, while its ammonium salt slightly changed the overall SERS signature. The inherently strong fluorescence of the shellfish tissue, which hampers Raman spectroscopy analysis, further increases when toxins are present in tissue. Through SERS, tissue fluorescence is partially quenched. Artificially intoxicated mussel tissue with DSP toxins and incubated with AgNPs allowed direct SERS evidence of the toxin presence, opening a novel avenue for the in situ shellfish tracking and warning via micro-SERS. Natural toxic tissue containing 57.91 μg kg YTX (LC-MS confirmed) was micro-SERS assessed to validate the new algorithm for toxins detection. We showed that a portable Raman system was able to reproduce the lab-based SERS results, being suitable for in situ raw seafood screening. The new approach provides an attractive, faster, effective and low-cost alternative for seafood screening, with economic, touristic and sustainable impact in aquaculture, fisheries, seafood industry and consumer trust.
为了检测和识别三种结构相关的海洋生物毒素，它们分别是引起腹泻性贝类中毒（DSP）症状的冈田酸（OA）、鳍藻毒素-1（DTX-1）和鳍藻毒素-2（DTX-2），以及结构不同的短裸甲藻毒素（YTX），我们开发了一种新的表面增强微拉曼散射（micro-SERS）方法，首次研究了它们在溶液中的 micro-SERS 信号，并与正常和有毒贻贝类组织一起进行了联合分析。YTX 出人意料地提供了与 DTX-1 和 DTX-2 非常相似的主要 SERS 特征，表明其与 AgNPs 具有相似的分子吸附机制。在 1017cm 处的特征指纹 SERS 带是 DTX-1 和 DTX-2 中 C-CH 伸缩的特征，而在 OA SERS 信号中不存在，这使得 DTX-1、2 可以直接与 OA 进行 SERS 区分。OA 以酸形式或以溶解的钾盐形式存在时，分别在 0.81µM 至 84.6nM 浓度下显示出可重复的 SERS 特征，而其铵盐略微改变了整体 SERS 特征。贝类组织固有的强荧光会阻碍拉曼光谱分析，当毒素存在于组织中时，荧光会进一步增强。通过 SERS，组织荧光部分被猝灭。用 DSP 毒素人工中毒的贻贝类组织与 AgNPs 孵育后，可以直接通过 SERS 证明毒素的存在，这为通过 micro-SERS 进行原位贝类跟踪和预警开辟了新途径。天然含毒组织含有 57.91µgkg YTX（LC-MS 确认），用 micro-SERS 进行了评估，以验证用于检测毒素的新算法。我们表明，便携式拉曼系统能够重现基于实验室的 SERS 结果，适合原位生海鲜筛选。该新方法为海鲜筛选提供了一种有吸引力、更快、有效且低成本的替代方法，对水产养殖、渔业、海鲜产业和消费者信任具有经济、旅游和可持续的影响。
