脱氧雪腐镰刀菌烯醇磁性表面分子印迹聚合物纳米颗粒的识别机理研究

Mycotoxin deoxynivalenol (DON) is seriously contaminated and frequently detected in foods and agricultural products, and thus is always paid significant attention on its routine analysis, monitoring and control within the whole framework of food safety administration.Practically,the existence of complicated biomatrices in sample preparation leads to the unavoidable drawbacks of low-efficiency during extraction procedure, as well as low detection limit, recovery and stability with regard to related applied analytical methods. Therefore, development of highly specific and selective adsorbents as fundamental materials in sample preparation is extremely important to overcome the above mentioned unsuffciencies, which is also under indeed needs there. In this proposal, using the smallest quantity of expensive DON as template molecule, novel magnetic molecularly imprinted polymer nanoparticles (M-MNPs) via surface imprinting against the target mycotoxin is firstly prepared. As designed,M-MNPs are expected to have the advantages of less volume and larger surface area, with Fe3O4@Au nanoparticles as supporting. Then, the nano-structure, specific surface area, selectivity, adsorption kinetics and thermodynamics characteristics of the obtained M-MNPs are thoroughly studied by multiple analyses via physical and chemical approaches, with optimization on the imprinting components. Furthermore, the recognition mechanism between the target molecule of DON and the M-MNPs are elucidated by the means of Nuclear Magnetic Resonance (NMR),Fourier Transform Infrared Spectroscopy (FTIR) and UV-visible spectroscopy, to reveal the key functional chemical groups responsible for the recognition steps. As resulted, the achieved data of this current research work will provide new funcational materials of specific adsorbents for preconcentration and clean-up of sample preparation.More importantly, the discovered theoretical evidences of recognition mechanism between the target DON and M-MNPs will open new avenues to substantially support the wide application of molecularly imprinted polymers as specific adsorbents for mycotoxin analyses in practical uses.

脱氧雪腐镰刀菌烯醇（deoxynivalenol, DON）在食品中的污染比例及检出率较高，是食品安全管理中日常检测、监测及控制的重点。但由于各种复杂生物基质的干扰，导致各种检测方法均存在提取效率低、检测灵敏度低、回收率低和稳定性差等缺陷。因而研究高选择性、高特异性的新型吸附材料及样品前处理方法至关重要。本项目创新性地以Fe3O4@Au纳米颗粒为载体，仅需少量模板分子，通过磁流体、表面分子印迹等方法，制备尺寸小、比表面积大的磁性分子印迹聚合物（M-MNPs）纳米颗粒。通过物理、化学等多种分析手段定量、系统研究M-MNPs的结构、比表面积、热力学、结合特性、选择特性等基础特性，优化印迹体系；同时利用核磁共振、红外光谱、紫外光谱等多种手段揭示DON M-MNPs与靶标DON分子的识别机理，明确起识别作用的重要功能基团。本项目研究结果将为新型分子印迹聚合物在真菌毒素实际检测中的应用提供理论依据。

脱氧雪腐镰刀菌烯醇（deoxynivalenol, DON）是由真菌产生的有毒代谢产物。对人和动物具有细胞毒性、免疫毒性、遗传毒性、生殖毒性和三致（致癌、致畸及致突变）作用。在加工和储藏过程中，饲料也易受真菌毒素污染。摄入发霉饲料的动物可将毒素及其代谢产物转移入动物源性食品中，从而进入到人饮食链中。.由于其在食品中的污染比例及检出率较高，是食品安全管理中日常检测、监测及控制的重点。但各种复杂生物基质的干扰，导致各种检测方法均存在提取效率低、检测灵敏度低、回收率低和稳定性差等缺陷。因而研究高选择性、高特异性的新型吸附材料及样品前处理方法至关重要。本试验采用分子印迹技术合成针对DON的吸附材料。实验中考虑到DON价格昂贵，首先建立了纯化制备DON的方法。该方法过程如下：禾谷镰刀菌接种大米培养基用于毒素产生，然后比较不同提取条件和净化方式对DON提取回收率和纯度的影响。提取液经制备液相分离后得到DON。纯化的DON通过紫外分光光度计、液相色谱、液相串联质谱、核磁共振及间接ELISA试验确证其结构和免疫特性。结果从100 g大米培养基中可纯化得到150 mg DON，纯度达98.93%。获得DON后，采用分子印迹技术合成针对DON的多种微米级聚合物。另外建立了同时测定饲料和原料中包括DON在内的多种B型单端孢霉烯族毒素的分析方法。该方法采用分散固相萃取法进行样品前处理，然后通过LC-MS/MS进行定量分析。基质相应校准曲线用于准确定量。试验结果表明该方法在一定浓度范围内呈良好线性关系（R2>0.9960），检出限（LOD）和定量限（LOQ）范围分别为1.93-7.92 μgkg-1，5.00-13.60 μgkg-1。回收率范围为79.03-118.39%，相对标准偏差（RSD）为2.73-17.50%。该方法样品前处理简单、快速，灵密度和回收率高。通过比较我们采用未用模板分子的聚合物进行体外体内试验。结果表明以4-乙烯基吡啶为功能单体、三羟甲基丙烯酸甲酯为交联剂合成的本底聚合物对DON有最高吸附能力，吸附效率约为50%。此外，以Fe3O4 作为功能性单体用于分子印迹的磁性纳米颗粒的制备，目前得到的印迹产物还没有明显的特异性吸附，该部分内容正在继续探索中。