title: Calorimetric Studies on Thermal Properties of Nano-Cryoprotectant Solutions during Vitrification.
abstract: BACKGROUND: Vitrification, the ice-free cryopreservation, develops rapidly and can become an ideal method for long-term preservation of cells and tissues. But up to now it is not practical for samples with large size because of the ultra-rapid cooling rate required. It has been reported that nanoparticles improve heat conductivity of solutions.
  
  
  
  In this study, Hydroxyapatite (HA) nanoparticles（20, 40 or 60nm）at 0.1 %, 0.5 % or 1 % (w/w) were added into glycerol solutions. Glass transition temperature and devitrification temperature of aqueous glycerol solutions with/without HA nanoparticles were measured by a differential scanning calorimeter(DSC) at a cooling rate of 150 degree C/min and a warming rate of 10 degree C/ min.
  
  
  
  Glass-transition temperatures and devitrification temperatures of glycerol aqueous solutions increased after the incorporation of HA nanoparticles. In the study using slow cooling rate of 10 degree C/min and warming rate of 5 degree C/min, the fraction of unfrozen water in the 50 % (w/w) glycerol solution increases steadily with the addition of HA nanoparticles. The findings have significant implications for biomaterial cryopreservation.
authors.affiliation: Institute of Biothermal Science, Shanghai University for Science and Technology, Shanghai, China.
authors.forename: H F
authors.initials: HF
authors.lastname: Xu
authors.affiliation: Institute of Biothermal Science, Shanghai University for Science and Technology, Shanghai, China.
authors.forename: B T
authors.initials: BT
authors.lastname: Hao
authors.affiliation: Institute of Biothermal Science, Shanghai University for Science and Technology, Shanghai, China.
authors.forename: L J
authors.initials: LJ
authors.lastname: Liu
authors.affiliation: Institute of Biothermal Science, Shanghai University for Science and Technology, Shanghai, China.
authors.forename: L L
authors.initials: LL
authors.lastname: Tang
authors.affiliation: Institute of Biothermal Science, Shanghai University for Science and Technology, Shanghai, China. blliuk@163.com.
authors.forename: B L
authors.initials: BL
authors.lastname: Liu
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry; D005990:Glycerol / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D044366:Transition Temperature; D058989:Vitrification
chemical_list: D001672:Biocompatible Materials; D003451:Cryoprotective Agents; D017886:Durapatite; D005990:Glycerol