Preparation and Characterization of Low Cost Asymmetric Thin Film as Accelerating Wound Healing Material

Abstract. Gelatin and sodium alginate bioblends of dissimilar ratio were prepared by casting. In order to prepare the asymmetric thin (AT) film, 2% CaCl^sub 2^ was incorporated in gelatin/sodium alginate blends. The physico-mechanical properties of the prepared films were investigated. AT film composed of gelatin and sodium alginate at a ratio of 70:30 with 2% of CaCl^sub 2^ showed higher tensile strength (25 MPa) and elongation at break (9%). The water and buffer uptake capacity of the gelatin/sodium alginate/CaCl^sub 2^ (70:30:2) blends was found to be higher than other blends. pH of this AT film was 7.82. Interaction among gelatin, sodium alginate and CaCl^sub 2^ in the films was tested and this film showed no cytotoxic effect.Key words: Gelatin, Sodium alginate, Asymmetric thin film, Cytotoxicity.(ProQuest: ... denotes formula omitted.)1 INTRODUCTIONIn recent years, there has been a considerable interest in the bioacceptable polymeric film, often known as asymmetric thin film (AT film) as advanced dressing material so that the tissues can be designed to grow in such a way that they match specifically the requirements of the individual in terms of size, shape and immunological compatibility, minimizing further requirement of treatment. The clinical success of the formulation is largely dependent on the quality of the starting scaffold composition that would promote not only the initial cellular adhesion but also the subsequent cell proliferation. Compared to the constituent polymers, the AT film has advantages when applied as coating membranes and controlled-release delivery systems. It is more stable to pH changes (Cascone, 1997 and Rathna et al., 1996) and has been proven more effective in limiting the release of encapsulated materials compared with either polymer alone (Smith, 1994; Elquin, 1995 and Yan et al. 2000). On the basis of their favorable physical properties, this study explored the potential of the gelatin-alginate PEC thin film for wound-dressing applications. Gelatin is a well-characterized protein fragment obtained by partial degradation of water insoluble collagen fiber (Sezer and Akbuga, 1999) and has been widely used in the biomedical field, because of its merits, including its biological origin, biodegradability, hydrogel properties, and commercial availability at a relatively low cost (Takeuchi et al., 2000). Gelatin is an intriguing candidate for drug delivery and is widely being used as tissue engineering scaffold. Cross-linked gelatin sponges have also been investigated for their application as a component of artificial skin or tissue transplants to promote epithelialization and granulation tissue formation in wound (Kniep and Simon, 2007). Gelatin has also been used in medicine as an artificial blood, plasma expander, wound dressing, adhesive, and absorbent pads for surgical use (Choi and Regenstein, 2000).Alginate hydrogels have shown excellent potential in a variety of biomedical applications, including scaffolds for tissue engineering or carriers for drug delivery systems (Ma, 2005). Commonly derived from seaweed, alginate is a linear polysaccharide consisting of β-Dmannuronic acid (M) and α-L-guluronic acid (G) monomers that are arranged in blocks of G, M, and random combinations of M and G monomers (G-, M-, and MG-blocks) (Ma, 2005 and Draget et al., 1991). By providing a relatively inert aqueous environment within its matrix and high gel porosity that follows for the diffusion of macromolecules, sodium alginate blends itself favorably to biomedical applications. In addition, it is water soluble and degradable under normal physiological conditions and may be applied to encapsulated materials under mild conditions that do not involve noxious organic solvents. When treated with calcium chloride, cooperative crosslinking occurs between calcium ions and G-blocks to result in an 'egg-box' structure that imparts gelling ability and mechanical strength (Rees, 1981). …