Hidrogel de colágeno e Ca10(PO4)6(OH)2 provenientes de tilápia do nilo e associados a Fe3O4@bPEI para aplicação em enxerto ósseo xenógeno

Abstract

The development of new products with high added value based on raw materials derived from fish processing residues opens possibilities for the sustainable advancement of the sector. In this work, the skins of Nile tilapia (Oreochromis niloticus) were used as raw material to obtain collagen, enabling the development of a collagenous matrix hydrogel associated with hydroxyapatite and incorporated with functionalized magnetic nanoparticles (Fe3O4, magnetite). Collagen was enzymatically extracted (pepsin) from pre-treated skins. The hydroxyapatite (HAp) used in this work was obtained from Nile tilapia scales. Magnetite was synthesized in a single step from solutions of Fe2+ and Fe3+ ions and functionalized with branched polyethyleneimine (bPEI). The hydrogels were prepared by UV-Riboflavin crosslinking, considering a collagen and HAp ratio of 4:1 (w/w), with 0.5%, 1.0%, 1.5% and 3.0% (w/v) of functionalized magnetite (Fe3O4@bPEI), totaling four samples: Col+HA+Fe3O4@bPEI_0.5%, Col+HA+Fe3O4@bPEI_1.0%, Col+HA+Fe3O4@bPEI_1.5%, and Col+ HA+Fe3O4@bPEI_3.0%. Collagen, functionalized magnetite, and hydrogels were characterized to determine their chemical, physical, and biological properties. The integrity of the triple helix of collagen was preserved after extraction, presenting, microscopically, a microfibrillar morphology suitable for its use as a matrix to produce hydrogels. The superparamagnetic behavior of Fe3O4@bPEI particles was satisfactory for biomedical applications, without hysteresis and with temperature increase (hyperthermia), when subjected to an external magnetic field. The collagenous matrix presented a porous structure, with the HA covering the surface of the collagen microfibrils. The Fe3O4@bPEI particles were successfully associated with the collagen and HAp matrix, obtaining hydrogels with a solid and consistent structure. Cell viability assays of the hydrogels did not show cytotoxic effects on fibroblasts (L929 cell line), with cell viability above 70%. For osteoblasts (MC3T3 cell line), cell viability above 70% was observed only for samples with a lower concentration of Fe3O4@bPEI. Among the proposed samples, the Col+HA+Fe3O4@bPEI_1.0% hydrogel showed more adequate cytocompatibility results, with potential application to act as a xenogeneic bone graft, which will both help in the bone regeneration process and in local hyperthermia to stop the growth or destroy cancer cells.