The Biological Effects Of Hydroxyapatite Nanoparticles Prepared By Different Dispersants

Hydroxyapatite nanoparticles(nHAP) can be widely applied in the biomedical field,especially in bone repairment,drug delivery,antitumor treatment and so on. However,because of special physical and chemical properties,nano-particles have significantly different characteristics compared with ordinary materials,which can lead to specific biological effects.Therefore,deep researches on the nHAP biological effects are favorable for the safety of the nHAP applications.This paper studies the biological effects of the HAP particles mainly on three areas,hemolysis,cytotoxicity and mitochondria superoxide dismutase(SOD) activity.The nHAP particles dispersed by heparin sodium and sodium polyacrylate,as well as the HAP particles dispersed by water were synthesized by chemical precipitation.Three different concentrations of the sols were prepared to test biocompatibility,low concentration,medium concentration and high concentration (1.4mg/ml,2.8mg/ml and 5.6mg/ml).The optical microscope photograph between HAP particles and red blood cells co-cultured in vitro,directly reflects the impacts of the materials on red blood cell.The results showed that all red blood cells were round and well-shaped.The low concentration of nHAP particles dispersed by the heparin sodium and sodium polyacrylate had no significant effects on red blood cells,but the low concentration HAP particles dispersed by water aggrevated and had greater impact on morphology and dispersion of red blood cells.The HAP particles hemocompatibility was researched by evaluation of red blood cells hemolysis.It was observed that the nHAP particles dispersed by heparin sodium had no significant hemolysis,but the nHAP particles dispersed by sodium polyacrylate and the HAP particles dispersed by water had significant hemolysis.The effect of nHAP particles dispersed by sodium polyacrylate on hemolysis was concentration dependent (P＜0.01).The results showed that particles size,concentration and dispersants of the HAP particles could affect the structure of red blood cells.The cell toxicity of the HAP particles was evaluated by MTT method and Alamar Blue method.The results of the two methods coincided basically and showed the lower concentration applied,the less influence on cell proliferation,and vise versa. The nHAP particles dispersed by heparin sodium had better cell compatibility than that dispersed by sodium polyacrylate,while the HAP particles dispersed by water had more inhibition on cells proliferation.Rat liver mitochondria was extracted,interacted with particles and then the superoxide dismutase(SOD) activity was determined.The results showed that the nHAP particles dispersed by heparin sodium had little impact on SOD,while the nHAP particles dispersed by sodium polyacrylate and the HAP particles dispersed by water had some impact on SOD.There were dose relationship between the inhibition and particle concentrations.Higher concentrations of HAP particles caused more inhibition of SOD activity.This paper researched on the biological effects of HAP particles through evaluation of red blood cells hemolytic,L929 cells proliferation,as well as superoxide dismutase(SOD) activity.The results showed that the nHAP particles dispersed by natural polysaccharide heparin sodium had better biocompatibility than that dispersed by the synthesized polymer sodium polyacrylate and the HAP particles dispersed by water.