Design of Novel Wound Dressing Composed of Collagen and Hyaluronic Acid Containing Epidermal Growth Factor

This research aims to develop a wound dressing composed of collagen (Col) and hyaluronic acid (HA) containing epidermal growth factor (EGF). First important issue is to contain EGF in the wound dressing in a stable state. The sheet-shaped sponge was manufactured by freeze-vacuum drying an aqueous solution of Col. Both sides of sponge were treated with ultraviolet (UV) irradiation to introduce intermolecular cross links between collagen molecules. This sponge was named Sponge-Col. Another sheet-shaped sponge was manufactured by freeze-vacuum drying an aqueous solution of HA containing EGF. This sponge was named Sponge-HA/EGF. The wound dressing was manufactured by laminating Sponge-Col on the top, Sponge-HA/EGF in the middle, and Sponge-Col on the bottom to create a sandwich structure. This method can prevent the reducing of EGF activity due to UV irradiation for intermolecular cross-linking. Second important issue is to enable gradual release of EGF from the wound dressing. The elution behavior of this wound dressing was investigated by measuring the weight change after immersion in water for a predetermined time. This wound dressing showed initially fast elution and subsequent very slow elution properties. The upper layer and lower layer Sponge-Col enabled gradual release of the middle layer Sponge-HA/EGF. This result suggests that EGF contained in the wound dressing is gradually released together with HA from the wound dressing. Third important issue is to provide moist wound-healing environment. The upper layer and lower layer Sponge-Col can provide the wound dressing with high water absorption and long-term water retention properties.