: Due to high biocompatibility and bioactivity, bioceramics are the most proper materials for the replacement or regeneration of human body soft and hard tissues. In recent years, thanks to high bioactivity and ability of osteogenesis as well as its activation of genes in osteoprogenitor cells, bioactive glass has been taken into great consideration. Likewise, hydroxyapatite, the mineral phase of bone, has been utilized in both synthetic and natural types. This study aimed at preparing and comparing the physico-chemical and biological properties of bioactive glass and bone-derived hydroxyapatite (HA) particles. 63S bioactive glass particles were obtained by sol-gel process and HA samples were derived from bovine bone. The chemical composition and the crystalline structure of both bioceramics were evaluated. Then the zeta potential in physiological saline and at different pH values was determined. In addition, in vitro cytotoxicity evaluation of bioglass nanoparticles, HA particles and bioglass-HA mixture (in similar weight percent) with human chondrocyte cells was carried out using isothermal micro-nano calorimetry (IMNC), which is a new method for studying cell/biomaterial interactions. For all three groups (bioglass, HA and bioglass-HA mixture) in vivo tests were carried out as well. It was found that the negativity of zeta potential for 63S bioglass is higher than that of bone-derived HA. The IMNC results confirmed the viability, growth and proliferation of human chondrocyte cells in contact with 63S bioactive glass and bone-derived HA particles. No positive effect for bioglass-HA mixture was observed. The results of in vivo tests showed that bioglass and HA were biocompatible and bioactive and can improve bone healing after 42 days implantation in rabbit tibia. In addition, an evident positive effect was observed for bioglass-HA mixture. The results confirmed that isothermal micro-nano calorimetry is a convenient method which caters to measuring the cell-biomaterial interactions alongside the current methods. It was also concluded that bioglass-HA mixture is more bioactive than bioglass and HA and therefore, can be replaced for bioglass and HA in all their applications. Keywords : Bioactive glass, Bone-derived hydroxyapatite, Physico-chemical properties, microcalorimetry
