Mineralização in vitro de matrizes colagênicas derivadas de tendões calcâneos bovinos e de avestruz / In vitro mineralization of anionic collagen scaffolds prepared from bovine and ostrich calcaneous tendons

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

One of greatest challenges of modern orthopedics is to restore bone tissue that has been lost due to sickness or accident. Searching for substitutes for grafts, biomaterials have been commonly used for recovery of bone tissue. Between different types of biomaterials, several are based on collagen. In addition to have important role in tissue structure, collagen is able to guide the formation of tissues, a highly favorable fact in its use as biomaterial. A possible research in collagen scaffolds mineralization is the analysis of how tissue organization interferes in deposition process. The tendon has been used because it is a highly organized tissue, with collagen fibers lined on its structure. This research aims the preparation and characterization of type I collagen scaffolds, prepared from bovine tendon (TB) and ostrich tendon (TA) after alkaline hydrolysis and mineralization. Tendons were maintained in alkaline solution containing K+, Na+ and Ca2+ ions for 72, 96 and 120 hours at 25°C and then equilibrated in salt solution, washed with H3BO3, EDTA and water. The resulting matrices were then mineralized in 0.2 mol L-1, pH = 7.4 CaCl2 solution and 0.12 mol L-1 Na2HPO4 pH = 9.0 for 6 h, changing solutions after 30 minutes. The matrices before and after mineralization were frozen, lyophilized and subjected to thermogravimetric analysis (TG), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR) and energy dispersive X-ray spectroscopy (EDS). DSC showed that the collagen was not denaturated by alkaline treatment process and mineralization. TG analysis showed deposition of calcium phosphate on the scaffolds, with values depending on the number of mineralization cycles. SEM showed that the mineralization is not uniform, forming clusters of phosphate crystals. FT-IR and EDS showed that the deposited calcium phosphate is probably hydroxyapatite, but not in its stoichiometric structure.

ASSUNTO(S)

mineralization tendons tendões colágeno mineralização collagen

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