Abstract: Abstract: Objective To investigate the absorption and release kinetics of BMP2 by hydroxyapatite nanoparticles (HANPs),and to analyze the potential of HANPs as a carrier for drug delivery systems.Methods BMP2 was radiolabeled with 125I according to the Iodogen method.HANPs were dispersed in BMP2 solutions with different concentrations.The absorption of BMP2 onto HANPs was detected using ITLCSG and γcounter.A suspension of HANPs/125IBMP2 was prepared in normal saline and incubated at 37 ℃ for 15 days.On each day,the release kinetics of BMP2 from HANPs was detected using ITLCSG and γcounter too.Results When the concentrations of BMP2 solutions ranged from 31.251 000 μg/mL,the absorption rate and the concentration of 125IBMP2 were positively correlated,and the amount of 125IBMP2 absorbed onto HANPs could be as high as 70 μg/mg.The release profile showed sustained release of BMP2 during the period of the investigation and the release ratio could increase moderately to about 43%.Conclusions These results suggest that HANPs has the potential function as a carrier for drug delivery systems and a scaffold material for bone tissue engineering.

Key words: Hydroxyapatite nanoparticles, BMP-2, Drug carrier, 125I labeling