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Basic fibroblast growth factor (bFGF) has been shown to stimulate wound healing. However, consistent delivery of bFGF has been problematic. We studied the stability of bFGF incorporated into a chitosan film as a delivery vehicle for providing sustained release of bFGF. The therapeutic effect of this system on wound healing in genetically diabetic mice was determined as a model for treating clinically impaired wound healing. A chitosan film was prepared by freeze-drying hydroxypropylchitosan (a water-soluble derivative of chitosan) acetate buffer solution. Growth factor was incorporated into films before drying by mixing bFGF solution with the hydroxypropylchitosan solution. bFGF activity remained stable for 21 days at 5 degrees C, and 86.2% of activity remained with storage at 25 degrees C. Full-thickness wounds were created on the backs of diabetic mice, and chitosan film or bFGF-chitosan film was applied to the wound. The wound was smaller in after 5 days in both groups, but the wound was smaller on day 20 only in the bFGF-chitosan group. Proliferation of fibroblasts and an increase in the number of capillaries were observed in both groups, but granulation tissue was more abundant in the bFGF-chitosan group. These results suggest that chitosan itself facilitates wound repair and that bFGF incorporated into chitosan film is a stabile delivery vehicle for accelerating wound healing.

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Articles you may be interested inPredominant growth of non-polar a-plane (Al,Ga)N on patterned c-plane sapphire by hydride vapor phase epitaxy J. Appl. Phys. 113, 093505 (2013); 10.1063/1.4794098 Polarity determination of a-plane GaN on r -plane sapphire and its effects on lateral overgrowth and heteroepitaxy J. Appl. Phys. 94, 942 (2003); 10.1063/1.1578530 Comparative study of GaN and AlN nucleation layers and their role in growth of GaN on sapphire by metalorganic chemical vapor depositionThe dependence of polar direction of GaN film on growth conditions has been investigated by changing either the group-V/group-III ratio ͑V/III ratio͒ in supplying the source gas or the deposition rate. GaN films were deposited on a nitrided sapphire by two-step metalorganic chemical vapor deposition. The surface morphology changed from flat hexagonal to pyramidal hexagonal facet with the increase of V/III ratio. However, the polar direction of GaN on an optimized buffer layer of 20 nm thickness was N-face (Ϫc) polarity, independent of both the V/III ratio and the deposition rate. The polarity of the GaN epitaxtial layer can be determined by that of an interface ͑nitrided sapphire, annealed buffer layer or GaN substrate͒ at the deposition of GaN epitaxial layer. The higher V/III ratio enhanced the nucleation density, and reduced the size of hexagonal facets. The nuclei, forming the favorable hexagonal facets of wurtzite GaN, should grow laterally along the ͕101 0͖ directions to cover a room among the facets until coalescence. After coalescence, Ϫc GaN growth on a flat hexagonal facet results in a pyramidal hexagonal facet. The growth mode for Ϫc GaN has been discussed with respect to surface structure and migration length of adsorbing precursors, in comparison with Ga-face (ϩc) GaN.