环丙沙星分子印迹聚合物自组装体系的分子模拟

Study on the Self-assembly System of Ciprofloxacin Molecular Imprinted Polymer by Molecular Simulation

关键词:  环丙沙星  分子印迹聚合物  功能单体  溶剂  计算模拟

Key words:  Ciprofloxacin  Molecularly imprinted polymers  Functional monomer  Solvent  Computer simulation

摘要:

以环丙沙星（CIP）为印迹分子，甲基丙烯酸（MAA）、4-乙烯基吡啶（4-Vpy）为功能单体，运用量子化学密度泛函理论（DFT）的LC-WPBE方法和6-31G (d, p) 基组，模拟CIP印迹分子与MAA、4-Vpy两种功能单体分子印迹聚合物自组装体系的构型，讨论了其稳定复合物的成键作用位点及数目、NBO电荷的转移及反应的结合能，探讨了CIP与两种功能单体之间相互作用的原理及分子印迹中溶剂的影响。模拟计算结果表明，CIP印迹分子哌嗪环上的N、喹啉羧酸上的H和O与两种功能单体均通过氢键作用形成在化学基团及空间结构上相互匹配的有序复合物；两种功能单体中MAA与CIP印迹分子间的相互作用更强，且在印迹比例为1:6，以甲苯为溶剂时，合成的复合物能量最低，对CIP的吸附性和识别能力更强。该分子模拟试验可为CIP分子印迹聚合物的进一步研究提供理论参考。

Abstract:

A molecular modeling approach was used to elucidate template - monomer interaction and the effect of solvent on recognition of molecularly imprinted polymers (MIPs). Ciprofloxacin (CIP) was taken as a template molecule. Methacrylic acid (MAA) and 4-vinyl pyridine (4-Vpy) were taken as functional monomers, respectively. Density functional theory (DFT) at the LC-WPBE/6-31G (d, p) level was used to investigate the geometry configurations optimization, the action sites, the natural bond orbital (NBO) charges, and the binding energies of the imprinted molecule with the monomers by means of Gaussian 09. The molecular imprinting mechanism of CIP and the monomers and the influence of solvent were discussed. Results indicated that the N atom on the piperazine ring and the carbonyl and the H atom on the quinoline carboxylic acid group of CIP interacted with MAA and 4-Vpy by hydrogen bonds. The imprinted molecule and the monomers formed ordered compounds that were mutual remedy in the chemical group and space structure. The interaction between CIP and MAA was stronger than that between CIP and 4-Vpy, and the polymer of the ratio of CIP-MAA (1:6) in toluene had lower energy. The details of the interaction between CIP and the two monomers were also given by this computing approach. The MIPs synthesized by CIP and MAA in toluene resulted in better molecular recognition ability and absorbability. The molecular simulation can provide a theoretical reference for the further study on CIP-MIPs.