Preparation and properties of peanut protein films crosslinked with citric acid

Solution cast films made from peanut proteins extracted from peanut meal and crosslinked with citric acid were found to have good dry and wet tensile properties but poor biocompatibility. Plant proteins are abundantly available, are non-immunogenic and can be used to develop films, fibers, nanoparticles and other types of materials for various applications. Previous attempts on developing films from peanut proteins have used high amounts of glycerol resulting in poor film properties. In this research, peanut proteins were made into films using 3-15% glycerol and the effect of film forming conditions on the tensile properties and thermal behavior was studied. Films were crosslinked with cytocompatible citric acid as the crosslinking agent. Ability of the crosslinked films to be used as substrates for tissue engineering was studied using mouse fibroblast cells. It was found that films developed in this research had much higher tensile strength and modulus than films previously developed from peanut proteins. Crosslinking with citric acid improved the dry and wet strengths of the films without affecting the water vapor permeability. Peanut protein films did not support the attachment and growth of mouse fibroblast cells suggesting that peanut proteins were cytotoxic.