Effects of Hydroxyapatite Nanoparticles on Devitrification Crystallization in Cryoprotectant Solutions

To study the effects of Hydroxyapatite(HA) nanoparticles on devitrification in cryoprotectant solutions,the crystallization of glycerol(60%,w/w) and PEG-600(50%,w/w) solutions with HA nanoparticles of different sizes(20 nm、 40 nm、60 nm)and different concentrations(0.1%、 0.5%)during warming were investigated by using differential scanning calorimetry(DSC) combined with cryomicroscopy.Experimental results showed that the presence of nanoparticles does not change the glass transition temperatures and melting temperatures of quenched solutions,but affects the behavior of devitrification and recrystallization upon warming.The morphologies of glycerol and PEG-600 solutions are dendritic and spheric respectively,and the structures are not changed by adding nanoparticles.The ice fraction of glycerol solution containing 0.1%60nm HA nanoparticles diminished significantly when comparing to the control solution.The ice fractions of PEG-600 solutions increased dramatically between-64℃ and-54℃.The findings have significant implications for biomaterial cryopreservation.