: Nowadays biodegradable polymers/bioactive ceramics composites with good physical and mechanical properties and biocompatibility are one of important subjects for researchers in bone tissue engineering. This study is focused on fabrication of nanocomposite scaffold of oly (3-hydroxybutyrate)/nanohydroxyapetite (PHB/nHA) via solvent-casting and particulate leaching technique and study of morphology and degradation mechanism of them. Therefore, scaffold samples have been prepared with PHB/chloroform solution with the PHB:NaCl weight ratio of 10:90, 15:85 and 20:80 . Amount of nHA has been varied for each series and it has been in range of 0-10 wt% belong to PHB. Porosity percentage of scaffolds has been calculated using deionized water diffusion method. Interaction between two phases of nanocomposites has been studied by using Furrier Transform Inferred (FTIR). Morphology and distribution of porosity, morphology and size of nHA and distribution of nHA in PHB matrix of scaffolds have been examined by using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX). It seems some hydrogen bonding interaction between carbonyl group of PHB and hydroxyl group and PO 4 3- of nHA. These reasons indicate the good interaction between nHA and PHB in the interface of nanocomposite for controlling size and morphology of nano particles. The SEM results have shown the porosity size in the range of 200-250µm. The interconnectivity of scaffold has been shown by the existing cavities on the wall of porosity for prepared scaffold with 90wt% NaCl. Decrease of porosity percentage of samples by increasing nHA is not significant. Degradation of nanocomposite scaffolds in Phosphate Buffer solution () T=38±2°C has been studied by measuring weigh of samples and measurement of pH for 102 days. SEM and FTIR analysis have been used for study of scaffold morphology and product of scaffold degradation after and before degradation. Weigh measurement of samples, measurement of pH and SEM image have illustrated that degradation of PHB/nHA scaffold is bulk degradation. Maximum degradation has been seen for prepared scaffold with 90wt% NaCl and 7.5wt% nHA. Generally if mechanical properties are not seen and according to results of all analysis, prepared scaffold with 90wt% NaCl and 7.5wt% nHA is preferred for growing bone cells on it. The obtained results suggest these newly developed PHB/nHA composite scaffolds may serve as a three-dimensional substrate in bone tissue engineering. Keywords: hydroxyapetite; nanocomposite; scaffold; poly (hydroxybutyrate); solvent-casting and particulate leaching, bone tissue engineering
