Abstract：
Free enzymes cause difficulties in many applications due to their insufficient stability, loss of activity in a short time, and most importantly, although they are costly, they are used only once in reactions, lose their effect and cannot be recovered from the environment. Magnetic nanoparticles coated with biocompatible polymeric material are potential candidates for promising enzyme carriers due to their multifunctional pore surfaces, easy removal from the environment provided by the magnetization, ability to main stability under various harsh conditions. This study prepared a biosensor candidate based on the inhibiting acetylcholinesterase enzyme by organophosphate pesticides from chitosan-coated magnetic nanoparticles doped with gold. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction diffractometry, and Fourier transform infrared spectroscopy analysis confirmed the structure of synthesized nanocomposites. Magnetic characteristics of the nanocomposites were assessed using VSM. Bio-nanocomposite (Fe3O4@Cht/Au/AChE) was used to determine environmental pollutants qualitatively. Remediation of organophosphate-containing wastewater is an essential issue for environmental sustainability. In this work, Dichlorvos and Chlorpyrifos were selected as organic pollutants to assess the enzymatic activity of immobilized Fe3O4@Cht/Au/AChE. Optimum conditions for AChE enzyme were immobilized nanostructures (Fe3O4@Cht/Au/AChE) were determined. The optimum pH for the immobilized enzyme was found to be 8, and the optimum temperature was found to be 60 °C. Retained immobilized enzyme activity is found to be around 50% for the 20th reuse. In the presence of 150 µL pesticide, retained immobilized enzyme activity is found to be around 25%. Method validation was performed for pesticides. When using immobilized AChE, the LOD (limit of detection)-LOQ (limit of quantitation) values for Dichlorovos and Chlorpyrifos was obtained in the range of 0.0087-0.029 nM and 0.0014-0.0046 nM, respectively. The relative standard deviation (RSD%) values, which are indicators of precision, were found to be below 2%.
摘要：
游离酶由于其稳定性不足而在许多应用中造成困难。在短时间内失去活性，最重要的是,尽管它们很昂贵，它们只在反应中使用一次，失去效果，无法从环境中恢复。涂有生物相容性聚合物材料的磁性纳米颗粒由于其多功能的孔表面而成为有前途的酶载体的潜在候选者。容易从磁化提供的环境中移除，在各种恶劣条件下的主要稳定性能力。这项研究基于有机磷酸酯农药抑制乙酰胆碱酯酶的生物传感器候选物，从壳聚糖包覆的磁性纳米颗粒中掺杂了金。透射电子显微镜，扫描电子显微镜，X射线衍射衍射法,傅里叶变换红外光谱分析证实了合成纳米复合材料的结构。使用VSM评估纳米复合材料的磁特性。生物纳米复合材料（Fe3O4@Cht/Au/AChE）用于定性测定环境污染物。含有机磷废水的修复是环境可持续性的重要问题。在这项工作中,选择敌敌畏和毒死蜱作为有机污染物，以评估固定化Fe3O4@Cht/Au/AChE的酶活性。确定了固定化AChE酶的最佳条件（Fe3O4@Cht/Au/AChE）。固定化酶的最适pH为8,最适温度为60℃。对于第20次重复使用，发现保留的固定化酶活性约为50％。在150微升杀虫剂存在下，发现保留的固定化酶活性约为25％。对农药进行方法验证。当使用固定化AChE时，敌百虫和毒死蜱的LOD（检测限）-LOQ（定量限）值在0.0087-0.029nM和0.0014-0.0046nM的范围内，分别。相对标准偏差(RSD%)值，它们是精度的指标，被发现低于2%。
