Elaboração de Compósitos de Nanohidroxiapatita e Colágeno Proveniente de Resíduos do Beneficiamento de Tilápia do Nilo (Oreochromis niloticus)

Abstract

Sustainable chemistry, or Green Chemistry, aims to improve processes, with the goal of becoming less waste, toxic waste and unwanted gases to the environment. One of its principles talks about processes that use raw materials from renewable sources to obtain new products. The fish waste discarded in the environment without control can cause damage such as eutrophication of water bodies. An alternative to add value to this waste is collagen extraction. There are several alternatives to the use of collagen, especially tissue engineering, where it is being used for the development of media, either alone or in combination with other materials. Collagen composite and hydroxyapatite have been widely studied. Applications extend from orthopedics and traumatology, as also in dentistry. This paper proposes the use of Nile Tilapia skins (Oreochromis niloticus), derived from fish processing waste, to obtain collagen and subsequently obtain composites nanohidroxiapatita, with potential application as bone graft. The skins were initially characterized as the moisture, protein, lipid and ash. Collagen extraction was performed using acetic acid 0.5 mol.L-1 and its characterization by Scanning Electron Microscopy, Spectroscopy Infrared Region with Fourier Transform, Absorption Spectroscopy UV-VIS, Zeta Potential, denaturation temperature and Differential Scanning Calorimetry. In preparing the composite for forming the nano-hydroxyapatite deposited on the surface of the collagenous matrix was used phosphoric acid solution 0.05 mmol.L-1 calcium chloride and 50 mmol.L-1 sodium hydroxide 0.1 mol.L-1 as precursors, with the composite characterized by Infrared Spectroscopy in the Region with Fourier Transform, Transmission Electron Microscopy, Scanning Electron Microscopy, Energy Dispersive Spectroscopy and X-ray diffraction. We found that the collagen maintained the integrity of the triple helix preserved showing no denaturation profile. The scanning electron microscopy allowed to investigate the morphology of collagen fibers and observe the deposition of particles of nanohidroxiapatita. The composite obtained showed characteristics similar to those of natural bone, such as Ca / P <1.67 compared, featuring a deficient hydroxyapatite calcium, the presence of carbonates in its composition, low crystallinity and even hydroxyapatite crystals at the nanometer scale.