Preliminary study of biological evaluation on hydroxyapatite nanoparticles

Hydroxyapatite (HAP) nanoparticles (NPs), which interfaces temporarily or permanently with viable tissues and cells, are in current use covering a wide range of medical applications, hence, it is indispensable to study the potential side effect acting on living organism, and to figure out the biocompatibility evaluation model of nanoparticles for standardization and methodology. In the present study, HAP NPs was selected within 30-80 nm. Cytotoxicity in vitro was analyzed by agar overlay and direct contact exposure test was conducted to evaluate the presence of potential HAP NPs which may induce toxic results to SD rat macrophages. Hemolysis test of NPs was performed in compliance with ISO 10993-12 guidelines. And the expression of HSP70 was determined by Western blotting. the results showed that HAP NPs could inhibit proliferation of macrophages when concentration was reached to 20 ¿g/ml, and the extent of haemolysis would be increased more than 5% while 1000 ¿g/ml NPs were contacted with rabbit blood cells. Furthermore,Western blot analysis showed that 100-¿g/ml HAP NPs up-regulated HSP70.The presented data suggested that the side effect of NPs on cells may not be avoided while selecting materials like HAP for biomedical application.