title: Surface modification of hydroxyapatite nanoparticles with thermal-responsive PNIPAM by ATRP.
abstract: Hydroxyapatite (HA) nanoparticles grafted by poly(N-isopropylacrylamide) (PNIPAM) brushes (PNIPAM-g-HA) have been synthesized by the surface-initiated atom transfer radical polymerization (ATRP) of N-isopropylacrylamide (NIPAM). The surface grafting amount of PNIPAM ranges from 15.5% to 46.4%. PNIPAM-g-HA has been characterized by FT-IR spectroscopy, thermal gravimetric analysis, X-ray diffraction, and scanning electron microscopy (SEM). The UV transmittance spectra and the particle size analysis of PNIPAM-g-HA in aqueous solution demonstrates that the PNIPAM-g-HA possess reversible thermal stimuli responsive properties. An in vitro bioactivity assessment indicates that PNIPAM-g-HA can induce the mineralization of Ca(2+) and HPO(4) (2-) and possesses an excellent bioactivity. The cell culture results show that the cells adhered to the surface of PNIPAM-g-HA grow better than on HA, and the area of the cells on the surface of PNIPAM-g-HA is much greater than for HA, which proves that the PNIPAM-g-HA has a better biocompatibility than HA.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Junchao
authors.initials: J
authors.lastname: Wei
authors.forename: Pan
authors.initials: P
authors.lastname: He
authors.forename: Aixue
authors.initials: A
authors.lastname: Liu
authors.forename: Xuesi
authors.initials: X
authors.lastname: Chen
authors.forename: Xianhong
authors.initials: X
authors.lastname: Wang
authors.forename: Xiabin
authors.initials: X
authors.lastname: Jing
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D002478:Cells, Cultured; D008855:Microscopy, Electron, Scanning; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013499:Surface Properties; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D000180:Acrylic Resins; C052970:poly-N-isopropylacrylamide