title: A biodegradable polymer-based coating to control the performance of magnesium alloy orthopaedic implants.
abstract: Magnesium and its alloys may potentially be applied as degradable metallic materials in orthopaedic implantations due to their degradability and resemblance to human cortical bone. However, the high corrosion rate and accumulation of hydrogen gas upon degradation hinders its clinical application. In this study, we adopt a new approach to control the corrosion rate by coating a controllable polymeric membrane fabricated by polycaprolactone and dichloromethane onto magnesium alloys, in which the pore size was controlled during the manufacturing process. The addition of the polymeric membrane was found to reduce the degradation rate of magnesium, and the bulk mechanical properties were shown to be maintained upon degradation. The in-vitro studies indicated good cytocompatibility of eGFP and SaOS-2 osteoblasts with the polymer-coated samples, which was not observed for the uncoated samples. The in-vivo study indicated that the uncoated sample degraded more rapidly than that of the polymer-coated samples. Although new bone formation was found on both samples, as determined by Micro-CT, higher volumes of new bone were observed on the polymer-coated samples. Histological analysis indicated no inflammation, necrosis or hydrogen gas accumulation on either of the samples during degradation. Collectively, these data suggest that the use of polymeric membrane may be potentially applied for future clinical use.
authors.affiliation: Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam, Hong Kong, China.
authors.forename: Hoi Man
authors.initials: HM
authors.lastname: Wong
authors.forename: Kelvin W K
authors.initials: KW
authors.lastname: Yeung
authors.forename: Kin On
authors.initials: KO
authors.lastname: Lam
authors.forename: Vivian
authors.initials: V
authors.lastname: Tam
authors.forename: Paul K
authors.initials: PK
authors.lastname: Chu
authors.forename: Keith D K
authors.initials: KD
authors.lastname: Luk
authors.forename: Kenneth M C
authors.initials: KM
authors.lastname: Cheung
mesh_terms: D000497:Alloys / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001826:Body Fluids / Q000378:metabolism; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000378:metabolism; D019245:Compressive Strength; D003343:Corrosion; D005260:Female; D005269:Femur / Q000166:cytology / Q000000981:diagnostic imaging / Q000601:surgery; D006801:Humans; D020007:Implants, Experimental; D008274:Magnesium / Q000737:chemistry / Q000378:metabolism; D008422:Materials Testing; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism; D011108:Polymers / Q000737:chemistry / Q000378:metabolism; D011817:Rabbits; D011859:Radiography; D013499:Surface Properties
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; D011091:Polyesters; D011108:Polymers; C016240:polycaprolactone; D008274:Magnesium