title: Sirolimus-loaded CaP coating on Co-Cr alloy for drug-eluting stent.
abstract: To achieve polymer-free and controllable drug-eluting system, there have been many efforts to modify the surface composition and topography of metal stent. Recently, calcium phosphate is commonly applied to metallic implants as a coating material for fast fixation and firm-implant bone attachment on the account of its demonstrated bioactive and osteoconductive properties. In the present study, the release of sirolimus could be controllable because of immobilization of sirolimus during the process of biomimetic CaP coating forming. A completely new concept is the drug carrier of biomimetic CaP coating with sirolimus for an absorbable drug eluting system, which in turn can serve as a drug reservoir. We here describe the characteristic, mechanisms and drug release in vitro of new drug-eluting system in comparison to conventional system equivalent. Nano-structured calcium phosphate (CaP) coating was formed on the cobalt-chromium (Co-Cr) alloy substrate. By immersing coated sample in solution with sirolimus (rapamycin), the sirolimus could be immobilized in the newly formed CaP layer. The morphology, composition and formation process of the coating were studied with scanning electron microscopy, energy dispersive spectrometer, X-ray diffraction and X-ray photoelectron spectroscopy. The results showed that a uniform CaP coating incorporated with sirolimus was observed on Co-Cr alloy.
authors.affiliation: Materials Science and Engineering, College of Mechanical and Electrical Engineering, Beijing Union University, Beijing 100020, China;; Beijing Engineering Research Center of Smart Mechanical Innovation Design Service, Beijing 100020, China;
authors.forename: Jingxin
authors.initials: J
authors.lastname: Yang
authors.affiliation: Atomic-Scale Surface Science Research Center, Yonsei University, Seoul 120-749, Korea and.
authors.forename: In-Seop
authors.initials: IS
authors.lastname: Lee
authors.affiliation: School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
authors.forename: Fuzhai
authors.initials: F
authors.lastname: Cui
keywords: Co-Cr alloy; drug-eluting system; sirolimus