title: Locally controlled release of basic fibroblast growth factor from multilayered capsules.
abstract: Biodegradable multilayered capsules encapsulating basic fibroblast growth factor (bFGF) were developed as a cytokine release carrier for drug delivery systems. The multilayered hollow capsules were fabricated via the layer-by-layer (LbL) assembly of chitosan (CT) and dextran sulfate (Dex). The bFGF was encapsulated into the CT/Dex multilayered capsules by controlling the membrane permeability, and the local and sustained release of bFGF from the capsules was examined. At pH < 8.0, the capsule membrane tightened, and FITC-dextran ( Mw = 4000) could not enter the capsules. However, FITC-dextran ( M w = 250000) easily entered the capsules at pH > 8.0, which can be attributed to the electrostatic repulsion of Dex caused by the deprotonation of the amine group in CT. After treatment with acetic acid buffer (pH 5.6), FITC-dextran or bFGF was successfully encapsulated into the capsules. The amount of encapsulated bFGF was approximately 34 microg/1 mg of capsule. Initially, about 30% of the encapsulated bFGF was released in serum-free medium within a few hours, however, the release was sustained over 70 h. When the bFGF encapsulating capsules were added to cell culture medium (serum-free), the mouse L929 fibroblast cells proliferated well for 2 weeks as compared to cultures, where bFGF was added to the medium or where bFGF and empty hollow capsules were added separately. The proliferation is due to the local and sustained release of bFGF from the adsorbent capsule to the cell surface.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Itoh
authors.forename: Michiya
authors.initials: M
authors.lastname: Matsusaki
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kida
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Akashi
mesh_terms: D000818:Animals; D002214:Capsules; D002462:Cell Membrane / Q000378:metabolism; D049109:Cell Proliferation; D048271:Chitosan / Q000737:chemistry; D016895:Culture Media, Serum-Free / Q000737:chemistry; D003692:Delayed-Action Preparations; D016264:Dextran Sulfate / Q000737:chemistry; D016222:Fibroblast Growth Factor 2 / Q000008:administration & dosage*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D051379:Mice; D010539:Permeability; D011994:Recombinant Proteins / Q000737:chemistry; D055672:Static Electricity
chemical_list: D002214:Capsules; D016895:Culture Media, Serum-Free; D003692:Delayed-Action Preparations; D011994:Recombinant Proteins; D016222:Fibroblast Growth Factor 2; D048271:Chitosan; D016264:Dextran Sulfate