title: In vitro and in vivo evaluation of the bioactivity of hydroxyapatite-coated polyetheretherketone biocomposites created by cold spray technology.
abstract: Polyetheretherketone (PEEK) is a material that is widely used in medicine because its mechanical properties show excellent similarity to those of human bone. However, because it is bioinert, PEEK shows limited ability to bind to natural bone tissue. Here, we applied a cold spray method to make a hydroxyapatite (HA)-coated PEEK hybrid material and evaluated its osteointegration in vitro and in vivo. With the cold spray method, the HA coating formed a homogeneous layer and adhered strongly to the PEEK disk implant. When the material was tested in vitro, early cell adhesion and viability improved. Alkaline phosphatase (ALP) activity and calcium concentration were also higher in cells cultured on HA-coated PEEK disks. In addition, the expression of osteoblast differentiation markers, such as ALP, bone sialoprotein and runt-related transcription factor 2, increased in these cells. For the in vivo test, we designed and implanted HA-coated PEEK cylinders into a rabbit ilium model by the press-fit method. The bone-implant contact ratio, trabecular number and trabecular thickness were determined using either three-dimensional microcomputed tomography or general two-dimensional histomorphometric analysis. This report demonstrates that the HA coating on the PEEK implant added with the cold spray method increased biocompatibility in vitro and promoted osteointegration in vivo, which suggests that the HA coating may improve the biofunctionality of various medical devices used in clinical applications.
authors.affiliation: Department of Orthopedic Surgery, College of Medicine, Seoul National University, SMG-SNU Boramae Medical Center, Seoul, Republic of Korea. spinelee@snu.snu.ac.kr
authors.forename: Jae Hyup
authors.initials: JH
authors.lastname: Lee
authors.forename: Hae Lin
authors.initials: HL
authors.lastname: Jang
authors.forename: Kyung Mee
authors.initials: KM
authors.lastname: Lee
authors.forename: Hae-Ri
authors.initials: HR
authors.lastname: Baek
authors.forename: Kyoungsuk
authors.initials: K
authors.lastname: Jin
authors.forename: Kug Sun
authors.initials: KS
authors.lastname: Hong
authors.forename: Jun Hong
authors.initials: JH
authors.lastname: Noh
authors.forename: Hyun-Kyung
authors.initials: HK
authors.lastname: Lee
mesh_terms: D001577:Benzophenones; D001709:Biotechnology / Q000379:methods; D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis*; D003080:Cold Temperature; D017886:Durapatite / Q000737:chemistry*; D005740:Gases / Q000737:chemistry; D007082:Ileum / Q000166:cytology* / Q000601:surgery*; D007659:Ketones / Q000737:chemistry*; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers
chemical_list: D001577:Benzophenones; D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D005740:Gases; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D017886:Durapatite