Improvement of biocompatibility with purified alginate for application in tissue engineering

M. LUZ TORRES; FERNANDEZ JUAN MANUEL; FERNANDO G. DELLATORRE; ANA M. CORTIZO; TAMARA G. OBERTI

Simposio; XII Simposio Argentino de Polímeros - SAP 2017; 2017

Alginate is a natural, water-soluble, polysaccharide obtained from brown algae consisting of β-Dmannuronate(M) and α-L-guluronate(G) residues (1→4). Due to many attractive features such as good biocompatibility, low toxicity as well as ease of hydrogel formation with divalent cations, it has been widely used in a variety of biomedical application, such as medical delivery and tissue engineering. These applications required highly purified materials. However the alginate extracted from brown seaweed and commercial alginate contain a large number of impurities, such as proteins and polyphenols, which might lead to an intense host immune reaction and reduce the biocompatibility of alginate. The brown algae, Undaria pinnatifida, native from Japan, China and Korea is a powerful invasive species which was introduced worldwide in different coasts, including the one of Puerto Madryn (Argentina). Sodium alginate can be obtained from this seaweed using and extraction process based on successive treatments with acid and alkaline solutions. In this study, we compare Undaria pinnatifida?s sodium alginate extracted from stem (SA) tissue with the commercial salt (Sigma Aldrich) and its derivates after a purification method based on chloroform/butanol and a posterior precipitation with ethanol and Na2CO3 salt. Samples characterization was performed by FTIR, TGA analysis and an intrinsic viscosity assay carried out with an Ostwald viscosimeter. These techniques showed that the purification procedure neither change the molecular structure nor the molecular weight of the alginate samples. In order to detect a toxic effect, cytotoxicity assays (NO production and MTT bioassay) were performed with a murine macrophage-like RAW 264.7 cell line. We showed that, through the purification procedure, alginate-induced cytotoxic effect in cultured macrophages was reduced and so biocompatibility improved. In conclusion, purified sodium alginate materials present a reduction of contamination by using a simple method that might generate a better biocompatibility than the unpurified ones (SA and commercial)