title: Physical and biological evaluations of sintered hydroxyapatite/silicone composite with covalent bonding for a percutaneous implant material.
abstract: A composite (HA/silicone) of hydroxyapatite (HA) microparticles with an average diameter of 2.0 micro m covalently linked to a silicone substrate has been developed, and its physical and biological properties as a percutaneous soft-tissue-compatible material have been evaluated. In tensile property measurement, samples of HA/silicone and the original silicone were similar in tensile strength, ca. 7.8 MPa, and elongation at break, ca. 570%. It was found that chemical surface modification with HA particles presented no mechanical disadvantage. In an adhesive-tape peeling test, scanning electron microscopic (SEM) observation showed that HA particles coupled directly to the substrate were not removed. HA particles may bond strongly with the substrate. In human periodontal ligament fibroblast attachment and proliferation experiments, the number of cells attached to HA/silicone was 14 times greater than that attached to the original silicone after 24 h of incubation. The value on HA/silicone was ca. 80% versus that on a tissue-culture plastic used as a positive control. After 72 h of incubation, the number of cells grown on HA/silicone increased to the level of the positive control. In observation of fluorescence microscopy stained by Hoechst 33342, cells appeared to tightly adhere to HA particles coupled to the silicone sheet due to intact nuclear morphology. Observation of cells by fluorescence dye with rhodamin phalloidin showed an extensive F-actin cytoskeleton on HA/silicone. In a 4-week animal implant test, force required to pull out the HA/silicone sheet was 15 times that of the original silicone. HA-particle coating on silicone with covalent linkage gave the inert surface bioactivity. The HA composite thus effectively prevents germ infection percutaneously.
authors.affiliation: Department of Bioengineering, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan. furuzono@ri.ncvc.go.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Furuzono
authors.forename: Pao-Li
authors.initials: PL
authors.lastname: Wang
authors.forename: Arata
authors.initials: A
authors.lastname: Korematsu
authors.forename: Kozo
authors.initials: K
authors.lastname: Miyazaki
authors.forename: Mari
authors.initials: M
authors.lastname: Oido-Mori
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kowashi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ohura
authors.forename: Junzo
authors.initials: J
authors.lastname: Tanaka
authors.forename: Akio
authors.initials: A
authors.lastname: Kishida
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D002455:Cell Division; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis*; D062109:Dermatologic Surgical Procedures; D017886:Durapatite / Q000737:chemistry*; D004548:Elasticity; D019544:Equipment Failure Analysis / Q000379:methods; D005260:Female; D005347:Fibroblasts / Q000166:cytology* / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D008420:Manufactured Materials; D008422:Materials Testing / Q000379:methods*; D008567:Membranes, Artificial; D016459:Prosthesis-Related Infections / Q000517:prevention & control; D051381:Rats; D017208:Rats, Wistar; D012828:Silicones / Q000737:chemistry*; D012867:Skin / Q000166:cytology*; D012879:Skin Physiological Phenomena; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D020099:Coated Materials, Biocompatible; D008567:Membranes, Artificial; D012828:Silicones; D017886:Durapatite