Purification of alginate improves its biocompatibility and eliminates cytotoxicity in matrix for bone tissue engineering

Abstract

There is a growing interest about using natural polymers from renewable sources as biomaterials for applications in tissue engineering. In the present work, alginates were extracted from Undaria pinnatifida, a brown sea weed invasive in Argentinian coast. The isolated alginate was structurally characterized by IR and 1H NMR spectroscopies, intrinsic viscosity and TGA. For comparison purposes, commercial sodium alginate was purified and characterized using the same protocol as for raw material. Toxicity and biocompatibility of sodium alginate obtained from algae were studied using a murine macrophage-like cell line (RAW 264.7) and bone marrow stromal cells (BMSC), respectively. The presence of impurities inhibited both RAW 264.7 and bone marrow stromal cell proliferation and increased nitric oxide production from macrophages, while inhibited osteoblastic differentiation of BMSC. All these effects were reverted by the purification of alginate. In conclusion, alginate purification improves biocompatibility and osteo-induction while decreases its toxicity.