Rodriguez Rebeca S, Szlag Victoria M, Reineke Theresa M, Haynes Christy L
Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.
Mater Adv. 2020 Dec 1;1(9):3256-3266. doi: 10.1039/d0ma00608d. Epub 2020 Oct 26.
A linear, methacrylamide polymer affinity agent was explored to capture two mycotoxins, deoxynivalenol (DON) and ochratoxin A (OTA), for multiplex surface-enhanced Raman scattering (SERS) detection. These mycotoxins are naturally occurring small molecules from fungi that can be dangerous at low concentrations. SERS detection was completed for each polymer-toxin complex at concentrations relevant to current safety regulation by the FDA: 1 ppm for DON and 5 ppb for OTA. Visibly distinguishable vibrational modes were observed in the multiplex spectra that were attributed to each mycotoxin individually, thus, not requiring any additional chemometric analysis. Density functional theory (DFT) was used to model DON and OTA to accurately label the vibrational modes in the experimental spectra as well as provide insight on the binding between both targets and the affinity agent. Fully modeled vibrations of these toxins are novel contributions due to OTA never being modeled and only a few published vibrational modes of DON. DFT guides empirical observations regarding hydrogen bonding at multiple sites of each mycotoxin target molecule through the amine groups on the polymer, confirming the capabilities of a single polymer affinity agent to facilitate multiplex detection of a class of molecules through less-specific interactions than traditional affinity agents.
一种线性甲基丙烯酰胺聚合物亲和剂被用于捕获两种霉菌毒素——脱氧雪腐镰刀菌烯醇（DON）和赭曲霉毒素A（OTA），以进行多重表面增强拉曼散射（SERS）检测。这些霉菌毒素是天然存在的真菌小分子，在低浓度下也可能具有危险性。针对每种聚合物 - 毒素复合物，在与美国食品药品监督管理局（FDA）当前安全规定相关的浓度下完成了SERS检测：DON为1 ppm，OTA为5 ppb。在多重光谱中观察到了可明显区分的振动模式，这些模式分别归因于每种霉菌毒素，因此无需任何额外的化学计量分析。利用密度泛函理论（DFT）对DON和OTA进行建模，以准确标记实验光谱中的振动模式，并深入了解两种目标物与亲和剂之间的结合情况。对这些毒素的完全建模振动是新的贡献，因为OTA从未被建模过，而DON只有少数已发表的振动模式。DFT通过聚合物上的胺基团指导了关于每个霉菌毒素目标分子多个位点氢键作用的实证观察，证实了单一聚合物亲和剂能够通过比传统亲和剂更不特异的相互作用来促进一类分子的多重检测。
