EGF containing gelatin-based wound dressings

In case of bulk loss of tissue or non-healing wounds such as burns, trauma, diabetic, decubitus and venous stasis ulcers, a proper wound dressing is n eeded to cover the wound area, protect the damaged tissue, and if possible to activate the cell proliferation and stimulate the healing process. In th is study, synthesis of a novel polymeric bilayer wound dressing containing epidermal growth-factor (EGF)-loaded microspheres was aimed. For this purpo se, a natural, nontoxic and biocompatible material, gelatin, was chosen as the underlying layer and various porous matrices in sponge form were prepar ed from gelatin by freeze-drying technique. As the external layer, elastome ric polyurethane membranes were used. Two different doses of EGF was added into the prepared gelatin sponges (1 and 15 mug/cm(2)) to activate cell pro liferation. EGF addition was carried out either in free form or within micr ospheres to achieve prolonged release of EGF for higher efficiency. The pre pared systems were tested in in vivo experiments on full-thickness skin def ects created on rabbits. At certain intervals, wound areas were measured an d tissues from wound areas were biopsied and processed for histological exa minations. The wound areas decreased upon low-dose EGF application but the difference between the affects of free EGF and microsphere loaded EGF was n ot so distinct. Upon increasing the dose of EGF by a factor of 15, it was o bserved that controlled release of EGF from microspheres provided a higher degree of reduction in the wound areas. Histological investigations showed that the prepared dressings were biocompatible and did not cause any mononu clear cell infiltration or foreign body reaction. The structure of the newl y formed dermis was almost the same as that of the normal skin. (C) 2001 El sevier Science Ltd. All rights reserved.