Electrophoretic Deposition of Gentamicin-Loaded Silk Fibroin Coatings on 3D-Printed Porous Cobalt-Chromium-Molybdenum Bone Substitutes to Prevent Orthopedic Implant Infections

Abstract

In addition to customizing shapes of metal bone substitutes for patients, the 3D printing technique can reduce the modulus of the substitutes through the design and manufacture of interconnected porous structures, achieving the modulus match between substitute and surrounding bone to improve implant longevity. However, the porous bone substitutes take more risks of postoperative infection due to its much larger surface area compared with the traditional casting solid bone substitute. Here, we prepared of gentamicin-loaded silk fibroin coatings on 3D-printed porous cobalt-chromium-molybdenum (CoCrMo) bone substitutes via electrophoretic deposition technique. Through optimization, relatively intact, continuous, homogeneous, and conformal coatings with a thickness of 2.30 ± 0.58 μm were deposited around the struts with few pore blocked. The porous metal structures exhibited no loss in mechanical properties after the anode galvanic corrosion in EPD process. The initial osteoblastic response on coatings was better than that on metal surface, including cell spreading, proliferation and cytotoxicity. Antibacterial efficacy experiments showed that the coatings had an antibacterial effect on both adherent and planktonic bacteria within 1 week. These results suggested that the beneficial properties of anode electrophoretic deposited silk fibroin coatings could be exploited to improve the biological functionality of porous structures made of medical metals.