In vivo study of self‐assembled alkylsilane coated degradable magnesium devices

Abstract

Magnesium (Mg) and its alloys are candidate materials for resorbable implantable devices, such as orthopedic devices or cardiovascular stents. Mg has a number advantages, including mechanical properties, light weight, its osteogenic effects and the fact that its degradation products are nontoxic and naturally present in the body. However, production of H gas during the corrosion reaction can cause formation of gas pockets at the implantation site, posing a barrier to clinical applications of Mg. It is therefore desirable to develop methods to control corrosion rate and gas pocket formation around the implants. Here we evaluate the potential of self-assembled multilayer alkylsilane (AS) coatings to control Mg device corrosion and formation of gas pockets in vivo and to assess effects of the AS coatings on the surrounding tissues in a subcutaneous mouse model over a 6 weeks' period. The coating significantly slowed down corrosion and gas pocket formation as evidenced by smaller gas pockets around the AS coated implants (ANOVA; p = 0.013) and decrease in the weight loss values (t test; p = 0.07). Importantly, the microCT and profilometry analyses demonstrated that the coating inhibited the pitting corrosion. Specifically, the roughness of the coated samples was ∼30% lower than uncoated specimen (p = 0.02). Histological assessment of the tissues under the implant revealed no inflammation or foreign body reaction. Overall, our results demonstrate the feasibility of use of the seld assembled AS coatings for reduction of gas pocket formation around the resorbable Mg devices. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018.

Preparation, characterization, and in vitro and in vivo biocompatibility evaluation of polymer (amino acid and glycolic acid)/hydroxyapatite composite for bone repair

“…The synthesized PAG/HA composite had a machinable melting temperature (204.5 • C), and it could be processed by injection molding. The TGA results showed that the onset of degradation of the PAG/HA composite occurred at 337 • C, and the The perfect degradable materials should be degraded to nontoxic matters, and the degradation rate should be controlled [21]. Initially, we assumed that the PAG polymer would possess more ester bonds than PAA owing to the incorporation of glycolic acid, with a moderate degradation rate.…”