Preparation of glucose-sensitive microcapsules with a porous membrane and functional gates

A glucose-sensitive microcapsule with a porous membrane and with linear-grafted polyacrylic acid (PAAC) chains and covalently bound glucose oxidase (GOD) enzymes in the membrane pores acting as functional gates was successfully prepared. Polyamide microcapsules with a porous membrane were prepared by interfacial polymerization, PAAC chains were grafted into the pores of the microcapsule membrane by plasma-graft pore-filling polymerization, and GOD enzymes were immobilized onto the PAAC-grafted microcapsules by a carbodiimide method. The release rates of model drug solutes from the fabricated microcapsules were significantly sensitive to the existence of glucose in the environmental solution. In solution, the release rate of either sodium chloride or VB12 molecules from the microcapsules was low but increased dramatically in the presence of 0.2 mol/L glucose. The prepared PAAC-grafted and GOD-immobilized microcapsules showed a reversible glucose-sensitive release characteristic. The proposed microcapsules provide a new mode for injection-type self-regulated drug delivery systems having the capability of adapting the release rate of drugs such as insulin in response to changes in glucose concentration, which is highly attractive for diabetes therapy. (C) 2004 Elsevier B.V. All rights reserved.

成功制备了一种具有多孔膜且膜孔中有线性接枝聚丙烯酸（PAAC）链以及共价结合葡萄糖氧化酶（GOD）作为功能门的葡萄糖敏感微胶囊。通过界面聚合制备了具有多孔膜的聚酰胺微胶囊，通过等离子体接枝填充聚合将PAAC链接枝到微胶囊膜的孔中，并通过碳二亚胺法将GOD酶固定在接枝PAAC的微胶囊上。所制备的微胶囊中模型药物溶质的释放速率对环境溶液中葡萄糖的存在高度敏感。在溶液中，氯化钠或维生素B12分子从微胶囊中的释放速率较低，但在存在0.2 mol/L葡萄糖时显著增加。所制备的接枝PAAC且固定GOD的微胶囊显示出可逆的葡萄糖敏感释放特性。所提出的微胶囊为注射型自调节药物递送系统提供了一种新模式，该系统能够根据葡萄糖浓度的变化调节胰岛素等药物的释放速率，这对糖尿病治疗极具吸引力。（C）2004 Elsevier B.V.保留所有权利。