title: Fabrication of an implantable fine needle-type glucose sensor using gamma-polyglutamic acid.
abstract: 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.
authors.affiliation: Department of Chemical Science and Technology, Institute of Science and Technology, The University of Tokushima, 2-1 Minamijosanjima, Tokushima 770-8506, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takaoka
authors.forename: Mikito
authors.initials: M
authors.lastname: Yasuzawa
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D015374:Biosensing Techniques / Q000191:economics / Q000295:instrumentation* / Q000379:methods*; D001786:Blood Glucose / Q000032:analysis*; D004563:Electrochemistry; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism; D006736:Horses / Q000097:blood; D007094:Imides / Q000737:chemistry; D009339:Needles; D011099:Polyglutamic Acid / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D019736:Prostheses and Implants; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012964:Sodium / Q000737:chemistry; D012995:Solubility; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D001786:Blood Glucose; D004800:Enzymes, Immobilized; D007094:Imides; D011108:Polymers; D014867:Water; D011099:Polyglutamic Acid; D012964:Sodium; D005949:Glucose Oxidase