Epidermis of Cereus hildmannianus as a biomimetic scaffold for tissue engineering

A thin plastic-like film separated from the epidermis of Cereus hildmannianus has excellent tensile strength, resistance to water and high antimicrobial activity and supports the growth of mouse fibroblast cells. Cactuses are one of the most under explored plant species with high potential for food, materials, pharmaceutical and other applications. Although studies have shown the ability of cactuses to be used for food, as a source for fibers, as reinforcement for composites and other applications, the role of individual layers and their properties has been studied to a limited extent. In this paper, a thin translucent layer was separated from the epidermis of C. hildmannianus and studied for its composition, structure and properties. The layer is composed of about 73% cellulose and 2% lignin and morphologically, shows surface with uneven and serrated edges. Films with length of up to 36 cm, strength of 6.8 MPa and elongation of 2.5% could be peeled from the cactus suggesting their suitability for food packaging and other applications. X-ray diffraction patterns and FTIR spectrums indicated that the films are similar to that of cellulose and major thermal degradation occurred above 280°C. Compared to standards, the cactus films showed about 41% and 44% inhibition against gram positive and gram negative bacteria and 67% inhibition of the common fungal strain (A. niger). Films showed high stability in water and to common chemicals. When used as substrates for mouse fibroblast cell growth, no cytotoxicity was observed and the cactus peel supported the attachment and proliferation of cells demonstrating potential to be used as a biomaterial for tissue engineering applications.