Abstract:In this work, chitosan and collagen-chitosan porous scaffolds were produced by the freeze drying method and characterized as potential skin substitutes. Their beneficial effects on soft tissues justify the choice of both collagen and chitosan. Samples were characterized using scanning electron microscope, Fourier Transform InfraRed Spectroscopy (FTIR) and thermogravimetry (TG). The in vitro cytocompatibility of chitosan and collagen-chitosan scaffolds was evaluated with three different assays. Phenol and titanium powder were used as positive and negative controls, respectively. Scanning electron microscopy revealed the highly interconnected porous structure of the scaffolds. The addition of collagen to chitosan increased both pore diameter and porosity of the scaffolds. Results of FTIR and TG analysis indicate that the two polymers interact yielding a miscible blend with intermediate thermal degradation properties. The reduction of XTT ((2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) and the uptake of Neutral Red (NR) were not affected by the blend or by the chitosan scaffold extracts, but the blend and the titanium powder presented greater incorporation of Crystal Violet (CV) than phenol and chitosan alone. In conclusion, collagen-chitosan scaffolds produced by freeze-drying methods were cytocompatible and presented mixed properties of each component with intermediate thermal degradation properties.

Different types of bone grafts are available in Brazil due to the increase of use of biomaterials for hard tissue replacement. This study was designed to evaluate the scientific production of Brazilian research groups on safety and efficacy of calcium phosphate bone grafts of commercial use in Brazil. The calcium phosphate bone grafts approved for commercial use in Brazil were searched at the National Health Regulatory Agency’s database (ANVISA). The main leaders’ names of the Brazilian Research Groups on these health technologies were obtained by applying the search strategies to the National Council of Technological and Scientific Development’s database (CNPq). Afterwards, it was performed a systematic search of studies conducted by these leaders on calcium phosphate bone grafts and published from 2000 to May 2008 at the following databases: Medline, Lilacs and Scielo. Twenty-nine bone grafts composed by calcium phosphates were registered at Anvisa in May 2008. From those products, 17 and 12 were from imported and national origin respectively. There were twenty-four Brazilian research groups on calcium phosphate bone grafts whose scientific production consisted of 5 studies on bone grafts registered at Anvisa: 3 experiments conducted in animals on the Brazilian bovine bone graft Gen-Ox®, one prospective comparative study and one case report both evaluating the clinical performance of a national biomaterial composed by BMP, demineralized bovine bone, inorganic bovine bone and bovine collagen with the commercial name Gen-Tech® for dentistry applications and 6 months of follow-up. However, all the included studies had poor methodological quality and could not be used for further recommendations despite their good results. The scientific evidence produced by the Brazilian research groups on safety and efficacy of calcium phosphate bone grafts of commercial use in Brazil is still scant. Additional studies are necessary to evaluate these technologies.