title: Surface modification of hydroxyapatite nanocrystals by grafting polymers containing phosphonic acid groups.
abstract: 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.
authors.affiliation: Nanomaterials Application Division, Korea Institute of Ceramic Engineering and Technology, 233-5 Gasan-Dong, Guemcheon-Gu, Seoul 153-801, Republic of Korea.
authors.forename: Hyung Woo
authors.initials: HW
authors.lastname: Choi
authors.forename: Hong Jae
authors.initials: HJ
authors.lastname: Lee
authors.forename: Kyung Ja
authors.initials: KJ
authors.lastname: Kim
authors.forename: Hyun-Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Sang Cheon
authors.initials: SC
authors.lastname: Lee
mesh_terms: 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
chemical_list: D063065:Organophosphonates; D011108:Polymers; D014867:Water; D017886:Durapatite