A multifaceted biomimetic interface to improve the longevity of orthopedic implants. (1st July 2020)

• Record Type: Journal Article
• Authors: Croes, Michiel; Akhavan, Behnam; Sharifahmadian, Omid; Fan, Haiyang; Mertens, Raya; Tan, Richard P.; Chunara, Aliza; Fadzil, Arifah A.; Wise, Steven G.; Kruyt, Moyo C.; Wijdicks, Sebastiaan; Hennink, Wim E.; Bilek, Marcela M.M.; Amin Yavari, Saber
• Is Part Of: Acta biomaterialia. Volume 110(2020)
• Page Start: 266
• Page End: 279
• Publication Date: 2020-07-01
• Subjects: Multi-functional biomaterials -- Metal 3D printing -- Plasma polymer films -- Bone morphogenetic proteins -- Bone integration -- Scaffolds; Biomedical materials -- Periodicals; 610.28
• DOI: 10.1016/j.actbio.2020.04.020
• Languages: English
• ISSNs: 1742-7061

Abstract

Abstract: The rise of additive manufacturing has provided a paradigm shift in the fabrication of precise, patient-specific implants that replicate the physical properties of native bone. However, eliciting an optimal biological response from such materials for rapid bone integration remains a challenge. Here we propose for the first time a one-step ion-assisted plasma polymerization process to create bio-functional 3D printed titanium (Ti) implants that offer rapid bone integration. Using selective laser melting, porous Ti implants with enhanced bone-mimicking mechanical properties were fabricated. The implants were functionalized uniformly with a highly reactive, radical-rich polymeric coating generated using a unique combination of plasma polymerization and plasma immersion ion implantation. We demonstrated the performance of such activated Ti implants with a focus on the coating's homogeneity, stability, and biological functionality. It was shown that the optimized coating was highly robust and possessed superb physico-chemical stability in a corrosive physiological solution. The plasma activated coating was cytocompatible and non-immunogenic; and through its high reactivity, it allowed for easy, one-step covalent immobilization of functional biomolecules in the absence of solvents or chemicals. The activated Ti implants bio-functionalized with bone morphogenetic protein 2 (BMP-2) showed a reduced protein desorption and a more sustained osteoblast response both in vitro and in vivo compared to implants modified through conventional physisorption of BMP-2. The versatile new approach presented here will enable the development of bio-functionalized additively manufactured implants that are patient-specific and offer improved integration with host tissue. Statement of Significance: Additive manufacturing has revolutionized the fabrication of patient-specific orthopedic implants. Although such 3D printed implants can show desirable mechanical and mass transport properties, they often require surface bio-functionalities to enable control over the biological response. Surface covalent immobilization of bioactive molecules is a viable approach to achieve this. Here we report the development of additively manufactured titanium implants that precisely replicate the physical properties of native bone and are bio-functionalized in a simple, reagent-free step. Our results show that covalent attachment of bone-related growth factors through ion-assisted plasma polymerized interlayers circumvents their desorption in physiological solution and significantly improves the bone induction by the implants both in vitro and in vivo . Graphical abstract: Image, graphical abstract