title: Fabrication of hydroxyapatite ultra-thin layer on gold surface and its application for quartz crystal microbalance technique.
abstract: We present a method for coating gold quartz crystal microbalance with dissipation (QCM-D) sensor with ultra-thin layer of hydroxyapatite nanocrystals evenly covering and tightly bound to the surface. The hydroxyapatite layer shows a plate-like morphology and less than 20 nm in thickness. The hydroxyapatite sensor operated in liquid with high stability and sensitivity. The in-situ adsorption mechanism and conformational change of fibrinogen on gold, titanium and hydroxyapatite surfaces were investigated by QCM-D technique and Fourier-transform infrared spectroscopy. The change of secondary structures of fibrinogen adsorbed on the surfaces depended on the adsorbed amounts of protein. The secondary structure of fibrinogen adsorbed on the surfaces changes with increasing coverage. This is explained by repulsion among fibrinogens, affecting water structure and thus the strength of fibrinogen interactions on the surface. The study indicates that the hydroxyapatite sensor is applicable for qualitative and conformational analysis of protein adsorption.
authors.affiliation: Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Monkawa
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ikoma
authors.forename: Shunji
authors.initials: S
authors.lastname: Yunoki
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Yoshioka
authors.forename: Junzo
authors.initials: J
authors.lastname: Tanaka
authors.forename: Dinko
authors.initials: D
authors.lastname: Chakarov
authors.forename: Bengt
authors.initials: B
authors.lastname: Kasemo
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry*; D005340:Fibrinogen / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D017433:Protein Structure, Secondary; D011791:Quartz / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D020099:Coated Materials, Biocompatible; D011791:Quartz; D006046:Gold; D005340:Fibrinogen; D017886:Durapatite; D014025:Titanium