This study aimed to develop porous hydroxyapatite scaffold for bone regeneration using the replica of the polymeric sponge technique. Polyurethane sponges were used with varying densities to obtain the scaffolds. The results indicate the porous HA scaffolds developed in this study as potential materials for application as bone substitutes to have high porosity (> 70%), chemical composition, interconnectivity and pore sizes appropriate to the bone regeneration.

Biocerâmicas porosas tem aplicações biomédicas importantes como preenchimento de defeitos ósseos e scaffolds na engenharia de tecidos. A hidroxiapatita (HA, Ca10(PO4)6(OH)2) que apresenta semelhança química e estrutural com a fase mineral dos ossos e dos dentes, é biocompatível e osteocondutiva, e tem excelente afinidade química e biológica com os tecidos ósseos. Este trabalho teve como objetivo desenvolver biocerâmicas porosas HA para utilização como scaffold para regeneração óssea empregando-se a técnica de réplica da esponja polimérica. A pasta biocerâmica de HA foi obtida por via úmida utilizando hidróxido de cálcio [Ca(OH)2] e ácido fosfórico (H3PO4) e impregnada em esponjas de poliuretano com diferentes densidades. Tratamento térmico a 600°C por 1h foi realizado para eliminação da esponja seguido da sinterização a 1100°C por 2 horas. Os scaffolds apresentaram a HA como fase majoritária, elevada porosidade (> 70%) e poros com tamanhos variando na ordem de macro (>100μm) e microporosidade (1-20μm), sendo estes fatores adequados para a aplicação como scaffolds para regeneração óssea.

There is a growing need for new biomaterials that can gain predictable and controlled tissue response, this is, that as bone graft substitutes should initiate new bone formation, after which they should get reabsorbed and replaced by bone tissue. This combination aims to improve the mechanical properties, degradation rates and absorption rates of biocompatibility and biodegradability. The aim of this study was to propose a synthetic route in which the HA was obtained by reaction of precipitation directly on evaluating the influence of chitosan biopolymer in the middle of precipitation in the characteristics of hydroxyapatite obtained. XRD analysis revealed the presence of HA phase with low crystallinity. In the FTIR analysis identified the characteristic bands of hydroxyapatite, as well as bands that characterize an interaction between chitosan and hydroxyapatite, as the band around 1050cm-1. SEM analysis of the biocomposites chitosan/HA, showed a dispersion of HA particles in chitosan, revealing a homogenous material and microporous.

In bioscience, there are several apatites constituteds by differents compositions. In the biological environment, apatites are found in bones and teeth of vertebrates with Ca/P ration from 2.0 to 0.5. It is not easy to determine the exact proportion of Ca2 + and PO43- in solution in the preparation of the process. In this study, apatites with Ca/P ration 1.0, 1.67 and 2.0 were prepared by direct reaction in an solution of H3PO4 in a suspension of Ca(OH)2, of same molarity, evalueting the crystallinity of CPP, Hap e TeCP with 1 mol/l, 3 mol/l and 5 mol/l. The samples characterized by X-ray diffraction (XRD) were compared with the standard of reference of the data base JCPDS. The composition of calcium phosphate for the differents molarity studied, resulted in a combination of phases with the exception of hydroxyapatite Ca/P ration 1.67 at concentrations 1 mol/l and 3 mol/l. But the diffractograms revealed that the increased molarity provided a decrease of some peaks of reflection of calcium phosphates with Ca/P ration 1.67. However, for the Ca/P ration 1.0 increasing the concentration, showed an increase of crystallinity of calcium phosphates. The FTIR confirmed the presence of phosphates in the spectrums around 1045 cm-1. The calcium phosphates obtained through direct reaction showed Ca/P ration is related with the technique employed, consolidating it in the preparation of these bioceramics.

The application of a hybrid composite consisting of biopolymer and calcium phosphate, similar morphology and properties of natural bone, may be a way to solve the problem of the fragility of ceramics without reducing its mechanical properties, retaining the properties of biocompatibility and high bioactivity. This work aims at the preparation and characterization of three-dimensional scaffolds composite HA / biopolymers (chitosan and gelatin). The freeze-drying technique was employed in this study to obtain these frameworks and partial results showed the effectiveness of this method. This involved the study of structural, chemical and morphological frameworks, in order to direct the research suggested the application. The X Ray Diffraction (XRD) and infrared spectroscopy and Fourier transform (FTIR) results confirmed the formation of hydroxyapatite (HA) phase and the presence of characteristic bands of HA and biopolymers in all compositions. The microstructure of the scaffolds study conducted by Scanning Electron Microscopy (SEM) revealed the formation of longitudinally oriented microchannels with interconnected pores. In all compositions the porous scaffolds showed varying sizes and mostly larger than 100μm, and is therefore considered materials with potential for application in bone tissue engineering.