Synthesis and ligand recognition of paracetamol selective polymers: semi-covalent versus non-covalent molecular imprinting
作者:Jenny P. Rosengren-Holmberg、Jesper G. Karlsson、Johan Svenson、Håkan S. Andersson、Ian A. Nicholls
DOI:10.1039/b900014c
日期:——
Three molecular imprinting strategies, each based upon a series of ethylene glycol dimethacrylate (EGDMA) cross-linked co-polymers, have been used to produce materials selective for the commonly used analgesic and antipyretic agent paracetamol (p-acetaminophen or 4-acetamidophenol) (1). The polymers were synthesised using either a semi-covalent imprinting strategy based upon 4-acetamidophenyl-(4-vinylphenyl) carbonate (4) or a non-covalent strategy based on methacrylic acid (MAA) as the functional monomer, or by employing a combination of these strategies. Radioligand binding studies demonstrated low template affinity in polymers offering only a single electrostatic interaction point for recognition via the phenolic residue in the template, whereas binding was substantially increased upon the introduction of a second binding mode, namely interaction at the acetamide moiety. HPLC analyses revealed no imprinting effect in the purely semi-covalent system, and only a minor effect in the purely non-covalent systems. However, a pronounced imprinting effect was demonstrated for polymers prepared by a combination of semi-covalent and non-covalent imprinting. This study illustrates a limitation of both the non-covalent and the semi-covalent strategies when it comes to achieving imprinted selectivity for small and poorly functionalised templates such as paracetamol. Parallels with conclusions from studies with antibodies are discussed.
我们采用了三种分子压印策略,每种策略都基于一系列乙二醇二甲基丙烯酸酯(EGDMA)交联共聚物,用于生产对常用镇痛解热剂扑热息痛(对乙酰氨基苯酚或 4-乙酰氨基苯酚)具有选择性的材料 (1)。聚合物的合成采用了以 4-乙酰胺基苯基-(4-乙烯基苯基)碳酸酯(4)为基础的半共价压印策略,或以甲基丙烯酸(MAA)为功能单体的非共价策略,或采用这些策略的组合。放射性配体结合研究表明,通过模板中的酚残基进行识别时,仅提供单一静电相互作用点的聚合物的模板亲和力较低,而引入第二种结合模式(即乙酰胺分子上的相互作用)后,结合力大幅提高。高效液相色谱分析显示,纯半共价体系中没有印迹效应,纯非共价体系中也只有轻微的印迹效应。然而,通过半共价和非共价压印组合制备的聚合物却具有明显的压印效果。这项研究表明,非共价和半共价策略在实现对扑热息痛等小分子和低官能度模板的压印选择性方面存在局限性。研究还讨论了与抗体研究结论的相似之处。