Parameters Analysis of Gelatin-carboxymethylcellulose Scaffolds Using Curve Fitting Method

Abstract

Biocompatible material called scaffold helps patient suffering from skin loss or skin disorder such as burn and ulcer. The scaffold allows the wound healing process to occur in suitable condition and heal faster. Gelatin and Carboxymethylcellulouse (CMC) were selected for scaffold fabrication where gelatin was mixed with CMC to strengthen the porous structure. Freeze drying method was used to form porous structure of the scaffold. Moreover, the scaffolds were further strengthed using dehydrothermal technique and chemical (EDC/NHS) crosslinking. The gelatin-CMC ratio was 100:0, 90:10, 80:20, 70:30, and 60:40. Since the scaffold has porous structure, the behavior of the material is foam-like hyperelastic material. The characterization of the material can be separated into two parts which are physical (characterization) and mechanical characterizations. The physical characterization, in this research, is to find an average pore size of the scaffold using scanning electron microscopy (SEM). The results show that the scaffold has pore size ranged between 117 µm to 197 µm which is in the appropriate range of the scaffold. For the mechanical characterization, at this stage, identification of material parameter, in this case, shear modulus were determined. Since the scaffold is hyperelastic material, the large deformation theory has been used to derive the constitutive equation to obtain the engineering stress equation in the form of Blatz-Ko hyperelastic model. The stress-strain curve was obtained from compressing test. The curve fitting method was used to identify the shear modulus of the scaffold. As a result, the 80:20 gelatin-CMC ratio scaffolds with chemical treatment has the highest shear modulus at 28.12±8.43 kPa. From the results, there are insignificant differences between non-treatment and dehydrothermal treatment scaffold. Two phenomenons which are the porous structure failure of chemically treated 90:10 gelatin-CMC scaffold and unchanged of shear modulus of 60:40 gelatin-CMC scaffolds must be further investigated.