Surface modification of hydroxyapatite nanocrystals by grafting polymers containing phosphonic acid groups.
A novel approach for the surface modification of hydroxyapatite (HAp) nanocrystals is described by grafting polymerization of vinyl phosphonic acid (VPA) using a redox initiating system in an aqueous media. Fourier transform infrared (FT-IR) and XRD analyses confirmed the modification reaction on HAp surfaces. Inductively coupled plasma mass spectroscopy (ICP MS) showed that the Ca/P molar ratio decreased from 1.67 to 1.36 with increasing the feed VPA amount. Zeta potentials of unmodified HAp and modified HAp in phosphate-buffered saline (PBS) solutions (pH 7.4, ionic strength = 10 mM) were negative and decreased with increasing the amount of grafted PVPA. Transmission electron microscopy (TEM) measurements and time-dependent phase monitoring indicated that the colloidal stability of modified HAp over unmodified HAp in water dramatically increased and tended to exist as single nanocrystals without aggregation.
Choi
Hyung Woo
HW
Nanomaterials Application Division, Korea Institute of Ceramic Engineering and Technology, 233-5 Gasan-Dong, Guemcheon-Gu, Seoul 153-801, Republic of Korea.
Lee
Hong Jae
HJ
Kim
Kyung Ja
KJ
Kim
Hyun-Min
HM
Lee
Sang Cheon
SC
D000327:Adsorption; D017886:Durapatite / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D063065:Organophosphonates / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013499:Surface Properties; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
D063065:Organophosphonates; D011108:Polymers; D014867:Water; D017886:Durapatite