Article Preview
TopIntroduction
Biodegradable materials research has become a very important area of study because of the critical need for environmentally friendly materials. Gelatin has been studied as a biodegradable polymer not only for its film forming properties but also for its availability and economical advantages over other synthetic biopolymers. Gelatin has been used in the food, pharmaceutical, biomedical, and photographic industries. In biomedical applications, gelatin has been developed for wound dressings, absorbent pads for surgical purposes, microspheres, and capsules (B. Chiou, Avena-Bustilos, R., Bechtel, P., Imam, S., Glenn, G., Orts, W., 2009; Gomez-Guillen, 2007; Rujitanaroj, 2008). Biowaste from the fishing industry has been reported to be 75% of the total weight of catches. Hence use of this material contributes greatly to environmental enhancement. Gelatin is a heterogeneous mixture of proteins extracted from mainly skin, tendons, ligaments, and bones (Choi, 1999). In a recent comparative study between bovine-hide and tuna-skin gelatin, the water solubility and the breaking force were similar for both types of gelatin, but the puncture deformation and water vapor permeability values were different (Gomez-Estaca, 2009). Mammalian gelatins are stronger, but fish gelatins are more elastic and able to become better deformable films, which is desirable for films in medical applications.
Typically Gelatin is solvent cast and made into films, scaffolds, electrospun mats, and coatings for implants. The effect of the gelatin concentration, addition of nanoclay, and drying temperatures on barrier and mechanical properties have been studied (B. Chiou, Avena-Bustilos, R., Bechtel, P., Imam, S., Glenn, G., Orts, W., 2009; Rao, 2007). Pure gelatin films have been successfully optimized in many studies with different plasticizers such as sorbitol and glycerol. Cao et al. reported that sorbitol increases the elongation at break while decreasing the tensile strength and elastic modulus in bovine gelatin films (Cao, 2009).Sorbitol decreases the thermal stability of gelatin films by affecting the protein-protein interactions. In a recent study, it has been determined that the best dressings for wound healing are transparent films, in terms of smooth epithelial cell growth and healing time (Mishra, 2008). These films were compared to xenografts, gauze, and calcium alginate dressings. The transparent films were found to be optimal in achieving fast, stable healing with reduced diabetic patient pain.