Takaoka Hiroki, Yasuzawa Mikito
Department of Chemical Science and Technology, Institute of Science and Technology, The University of Tokushima, 2-1 Minamijosanjima, Tokushima 770-8506, Japan.
Anal Sci. 2010;26(5):551-5. doi: 10.2116/analsci.26.551.
Implantable fine needle-type glucose sensors with an outer diameter of less that 0.2 mm were fabricated using a low-cost and non-animal origin polyamide, gamma-polyglutamic acid (PGA) as a glucose oxidase (GOx) immobilizing material. Two types of PGA, gamma-polyglutamic acid (PGAH) and gamma-polyglutamic acid sodium salt (PGANa), were employed to prepare GOx immobilized film by the covalent attachment of GOx using water-soluble carbodiimide (EDC). Nafion/cellulose acetate composite film and polyurethane/polydimethylsiloxane composite film were employed as a permselective inner film and a biocompatible outer film, respectively. The procedure of enzyme-immobilized film fabrication affected the stability of the sensor; that is, GOx immobilized film prepared by pouring a mixture solution of GOx and EDC on a PGA precoated surface showed higher sensor stability than that prepared by pouring a mixture solution of GOx, PGA and EDC. Although, obvious differences in the sensor properties were not observed between the use of PGANa and PGAH, the electrode prepared with PGAH had a lower swelling degree. The glucose sensors prepared with both PGANa and PGAH were practically not affected by the existence of electroactive compounds, such as uric acid, and provided long-term stability for approximately 5 weeks. These sensors also showed good performance in horse serum.
采用低成本且非动物源的聚酰胺——γ-聚谷氨酸（PGA）作为葡萄糖氧化酶（GOx）固定材料，制备了外径小于0.2毫米的可植入细针型葡萄糖传感器。使用两种类型的PGA，即γ-聚谷氨酸（PGAH）和γ-聚谷氨酸钠盐（PGANa），通过水溶性碳二亚胺（EDC）共价连接GOx来制备GOx固定膜。分别采用Nafion/醋酸纤维素复合膜作为选择性渗透内膜，聚氨酯/聚二甲基硅氧烷复合膜作为生物相容性外膜。酶固定膜的制备过程影响传感器的稳定性；也就是说，将GOx和EDC的混合溶液倒在预涂PGA的表面上制备的GOx固定膜，其传感器稳定性高于将GOx、PGA和EDC的混合溶液倒在一起制备的膜。虽然在使用PGANa和PGAH之间未观察到传感器性能的明显差异，但用PGAH制备的电极溶胀度较低。用PGANa和PGAH制备的葡萄糖传感器实际上不受尿酸等电活性化合物存在的影响，并提供约5周的长期稳定性。这些传感器在马血清中也表现出良好的性能。
