Reaction of protein and carbohydrates with EDC for making unique biomaterials

Authors: Taylor, Maryann; Bumanlag, Lorelie; Brown, Eleanor - Ellie; Liu, Cheng Kung

Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2015
Publication Date: 4/1/2016
Citation: Taylor, M.M., Bumanlag, L.P., Brown, E.M., Liu, C. 2016. Reaction of protein and carbohydrates with EDC for making unique biomaterials. Journal of American Leather Chemists Association. 111(4):155-164.

Interpretive Summary: We have previously demonstrated the viability of using chemical and enzyme treatments on protein and carbohydrate waste products for the purpose of making products to enhance the properties of leather. These treatments were effective in reacting with gelatin, whey protein concentrate (WPC), and/or chitosan, alone or in combinations, to give products with interesting functional properties. All crosslinkers were either natural products and/or sustainable materials. In our continuing studies of chemical and enzymatice methods to crosslink gelatin and carbohydrates, we investigated the widely reported 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) which has been used to crosslink proteins for the purpose of making biomaterials. This study examined the reactivity of various concentrations of the chemical EDC, a carbodiimide, with gelatin, chitosan and combinations of both, at optimal times, and temperatures, and the effect these parameters have on physical properties, such as melting point and viscosity. It was found that both gelatin and chitosan had reactivity with EDC and the physical properties reflected the concentration of both the carbodiimide (EDC) and the quality of gelatin. It was found however that when the gelatin and chitosan were reacted together in the presence of the carbodiimide (EDC), the physical properties improved significantly over the protein and carbohydrate when they were reacted separately, resulting in unique products. This preliminary study will lead to a better understanding of the reactivity of carbodiimide, EDC, and optimal conditions for developing appropriate products. Forthcoming studies, in which less expensive water soluble carbodiimides with desirable functionality, will be investigated for the purpose of making unique products, such as films, coatings, fillers, and/or flocculants for effluent treatment.

Technical Abstract: Prior research from this laboratory has demonstrated the feasibility of using chemical and enzymatic treatments on protein and carbohydrate waste products for the purpose of making fillers to enhance the properties of leather. These treatments (microbial transglutaminase, genipin, and polyphenols in the form of vegetable tannins), were effective in reacting with gelatins, whey protein concentrate (WPC), and/or chitosan, alone or in combinations, to give products with interesting functional properties. All crosslinkers were either natural products and/or sustainable materials. In our continuing studies of chemoenzymatic methods to crosslink collagen and collagen by-products, we investigated the extensively reported 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), which has been used to crosslink proteins for purpose of making biomaterials. This present study examined the reactivity of various concentrations of EDC with gelatin, chitosan and combinations of both, in the presence and absence of N-hydroxysuccinimide (NHS) at optimal times, and temperatures, and the effect these parameters had on physical properties, molecular weight distribution and free amine content. It was found that both gelatin and chitosan had reactivity with EDC and the physical properties reflected the concentration of both the carbodiimide and gelatin. It was found however that when the gelatin and chitosan were reacted together in the presence of the carbodiimide, the physical properties improved significantly over the protein and carbohydrate when reacted separately, resulting in unique products. This study provides a better understanding of the reactivity of carbodiimide and optimal conditions for developing appropriate products.