title: β-Cyclodextrin grafted polyethyleneimine hydrogel immobilizing hydrophobically modified glucose oxidase.
abstract: Hydrogels which release their contents in response to glucose concentration were prepared by immobilizing glucose oxidase (GOD) into β-cyclodextrin grafted polyethyleneimine hydrogels (PEI-βCD hydrogel). For the tight immobilization, hydrophobically modified GOD (HmGOD) was prepared by reacting GOD with palmitic acid-N-hydroxysuccinimide ester (PA-NHS) in the molar ratio of 1:40. According to trinitrobenzene sulfonic acid (TNBS) assay, five palmitic acids were covalently attached to one GOD molecule. The activity of HmGOD was about 76% of native enzyme. The swelling ratios of HmGOD loaded hydrogels increased from about 960% to 1190% in 24h, when glucose concentration was varied from 0 to 100mg/dl. The % release in 48 h of fluorescein isothiocyanate dextran increased from about 53% to 89%, when glucose concentration was varied in the same range. Gluconic acid, produced by the enzymatic reaction, would protonate and swell the PEI-βCD hydrogel, leading to a higher release.
authors.affiliation: Polymer Chemistry, Material Chemistry Department, Uppsala University, S-751 21 Uppsala, Sweden.
authors.forename: Xia
authors.initials: X
authors.lastname: Yang
authors.forename: Jin-Chul
authors.initials: JC
authors.lastname: Kim
mesh_terms: D003911:Dextrans; D004800:Enzymes, Immobilized / Q000737:chemistry*; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives; D005947:Glucose / Q000737:chemistry; D005949:Glucose Oxidase / Q000737:chemistry*; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D010169:Palmitic Acids / Q000737:chemistry; D011094:Polyethyleneimine / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014302:Trinitrobenzenesulfonic Acid; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D003911:Dextrans; D004800:Enzymes, Immobilized; D010169:Palmitic Acids; D047392:beta-Cyclodextrins; C015219:fluorescein isothiocyanate dextran; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D014302:Trinitrobenzenesulfonic Acid; D011094:Polyethyleneimine; D005949:Glucose Oxidase; D016650:Fluorescein-5-isothiocyanate; D005947:Glucose; C031215:betadex