金属–有机框架固载蛋白酶复合材料的构筑及催化性能研究

Aiming at the traditional protein enzyme immobilized carriers, which neither provide the accurate structure information of channels and surface to research the structure-activity relationship, nor efficiently play the role of the catalytic function, in this project, it makes full use of the advantages of the crystalline porous metal–organic frameworks, which can supply the precise structural information, high porosity, large pore volume, the tunable structure and the convenient defect design, to offer the new approach to solve the above problems. This project adopts the catalytic function oriented porous carrier materials to design three kinds of metal–organic framework materials at the molecule level, and further tailor the host frameworks or generate the new function via the functionalization and modification of the ligands. From the perspective of the functional enzymes, three kinds of enzymes are selected. The functional pore space of metal–organic frameworks is used as microreactors to confinedly encapsulate and enhance the enzyme catalytic properties even with the coordinate effect. Through exploring the design method of composites, the matching rules and the encapsulating approach between the host frameworks and the enzymes, it will reveal the intrinsic natures between the structure of channels and the catalytic performances of the composites, deeply understand the advantage and limitation of this kind of the composites, and provide the theoretic and pratical support for the design of the immobilized enzyme carriers and the application of the enzyme immobilization.

针对传统多孔蛋白酶固定化载体不能提供精确的孔道和表面结构信息来探究酶固定化后活性与稳定性的关系，以及不能有效发挥蛋白酶的催化功能等瓶颈问题，本项目利用多孔金属–有机框架晶态材料可提供详细结构信息、高孔隙率、孔结构可调变和易设晶体缺陷等优势，实现对蛋白酶的有效封装，探索解决这些问题的新途径。以催化功能为导向，从多孔载体材料角度入手，在分子水平设计三种不同类型的金属–有机框架材料，并进行功能配体修饰，优化主体框架功能或衍生新功能；从功能蛋白酶角度入手，选择三类功能蛋白酶，以金属–有机框架的功能空间为微反应器，进行限域封装强化原有酶的催化特性甚至产生协同效应；研究此类复合材料的设计方法、主体材料与蛋白酶的匹配规律和封装途径，揭示复合材料孔道结构-催化性能之间的内在本质关系，深刻认识此类复合材料的优势和局限性，为蛋白酶固定化载体的设计合成和固定化应用提供理论和实验依据。

金属-有机框架是由金属结点和连接子通过自下而上的途径自组装形成的多孔材料，可用于蛋白酶的固载。一系列具有高稳定性和高孔道金属-有机框架被合成或筛选为主体，像ZIF-8和Uio-66系列，脂肪酶和胃蛋白酶为客体，被成功固定到金属-有机框架内，形成enzyme/MOF复合物。分别以(±)-1-苯基乙醇的酯化反应和电辅助催化水解为催化模型，酶的负载过程、固载形态、负载量、催化活性、循环性和酶/MOFs复合物的耐受性和使用寿命被系统性地探究。总的来说，酶被负载在金属-有机框架内，其活性可以得到很好的保持，证明金属-有机框架可以作为很好的蛋白酶载体。项目执行期间项目成员继续承担国家自然科学基金项目4项，中原科技创新领军人才项目1项，河南省优秀青年科学基金项目1项，河南省高校科技创新人才支持计划项目2项，研究成果获河南省科技进步二等奖一项，河南省自然科学三等奖一项。在Chem. Sci., J. Mater. Chem. A., Adv. Opt. Mater, Chem. Commun., Inorg.Chem., Cryst. Growth. Des.等国内外期刊发表SCI收录论文23篇，培养博士、硕士研究生12名，已毕业硕士研究生8名。