https://doi.org/10.1016/j.bioactmat.2022.01.042

A programmed surface on polyetheretherketone for sequentially dictating osteoimmunomodulation and bone regeneration to achieve ameliorative osseointegration under osteoporotic conditions

Metallic biomaterials are widely used in implants to strengthen, repair, or replace damaged bone tissue, and their material characteristics have direct influences on short- and long-term implant performance. Of these, titanium and its alloys are the most widely applied due to their superior corrosion resistance, biocompatibility, and mechanical properties, such as in joint replacements, dental implants, and spinal fusion cages. However, Ti and Ti alloys are bioinert materials that have difficulty in binding directly to bone tissue after implantation, due to a lack of osteoconductive and osteoinductive properties. Bacterial adhesion and colonisation at the implantation site may also lead to infection-associated complications. The surface of the titanium implant directly interfaces with blood, cells, and tissues in vivo, and the surface properties can have profound influences on protein- and cell-based interactions that then promote or impede osseointegration. Therefore, the material surface morphology, chemistry and antibacterial function are key parameters in implant design, and contribute to determining the long-term success of the implant. In this review, we systematically present the latest advances in surface modification techniques for orthopaedic implants, including mechanical, physical, chemical, and biological modification. We also analyse and compare different surface modification approaches, including drug loading, metallic element doping, and bionic coatings, as well as topographical modifications such as nanotubes, nanopores and nanowires. Finally, we present a critical analysis and future perspectives on the use of surface modifications to improve the osseointegration and antibacterial properties of orthopaedic implants.

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Advances in implant surface modifications to improve osseointegration

Titanium (Ti) and its alloys have been widely used in clinics as preferred materials for bone tissue repair and replacement. However, the lack of biological activity of Ti limits its clinical applications. Surface modification of Ti with bioactive elements has always been a research hotspot. In this study, to promote the osseointegration of Ti6Al4V (Ti64) implants, calcium (Ca), oxygen (O), and phosphorus (P) codoped multifunctional micro-nanohybrid coatings were prepared on a three-dimensional (3D) printed porous Ti64 surface by microarc oxidation (MAO) and a hydrothermal method (HT). The surface morphologies, chemical compositions, and surface/cell interactions of the obtained coatings were studied. In vitro experiments indicated that all hybrid coating-modified Ti64 implants could enhance protein adsorption and MC3T3 osteoblasts' activity, adhesion, and differentiation ability. In vivo experiments showed that the hybrid coating promoted early osseointegration. By comparison, microarc oxidation-treated Ti64 (M-Ti) has the best biological activity and the strongest ability of osseointegration. It provides important theoretical significance and potential application prospects for improving the biological activity of Ti implants.

Comparative Study on 3D Printed Ti6Al4V Scaffolds with Surface Modifications Using Hydrothermal Treatment and Microarc Oxidation to Enhance Osteogenic Activity.

Currently, the gold standard for aesthetic and functional reconstruction of critical mandibular defects is an autologous fibular flap; however, this carries risk of donor site morbidity, and is not a promising option in patients with depleted donor sites due to previous surgeries. Tissue engineering presents a potential solution in the design of a biomimetic scaffold that must be osteoconductive, osteoinductive, and support osseointegration. These osteogenesis-inducing scaffolds are most successful when they mimic and interact with the surrounding native macroand micro-environment of the mandible. This is accomplished via the regeneration triad: (1) a biomimetic, bioactive osteointegrative scaffold, most likely a resorbable composite of collagen or a synthetic polymer with collagen-like properties combined with beta-tri calcium phosphate that is 3D printed according to defect morphology; (2) growth factor, most frequently bone morphogenic protein 2 (BMP-2); and (3) stem cells, most commonly bone marrow mesenchymal stem cells. Novel techniques for scaffold modification include the use of nano-hydroxyapatite, or combining a vector with a biomaterial to create a gene activated matrix that produces proteins of interest (typically BMP-2) to support osteogenesis. Here, we review the current literature in tissue engineering in order to discuss the success of varying use and combinations of scaffolding materials (i.e., ceramics, biological polymers, and synthetic polymers) with stem cells and growth factors, and will examine their success in vitro and in vivo to induce and guide osteogenesis in mandibular defects.

/pdf/tissue-engineering-in-mandibular-reconstruction-osteogenesis-1zcj85olzz.pdf

Tissue engineering in mandibular reconstruction: osteogenesis-inducing scaffolds

Metal phosphates represent an important group of materials with established industrial applications that are still attracting special scientific interest, owing to their outstanding physical and chemical properties. In this review, we account on the different synthetic routes and applications of zirconium and titanium phosphates, with a special focus on their application in the medicinal field. While zirconium phosphate has been extensively studied and explored with several reported industrial and medicinal applications, especially for drug delivery applications, titanium phosphates have not yet attracted the deserved attention regarding their established applications. However, titanium phosphates have been the focus of several structural studies with their different polymorphic forms, varied chemical structures, and morphologies. These variations introduce titanium phosphates as a strong candidate for technological and, particularly, biomedical applications.

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A Review on the Synthesis and Current and Prospective Applications of Zirconium and Titanium Phosphates

In this study, a series of hierarchical micro/nanoscaled titanium phosphate (TiP) coatings possessing various surface morphologies were successfully fabricated on titanium (Ti) discs. The hydrothermal reactions of Ti discs in hydrogen peroxide (H2O2) and phosphoric acid (H3PO4) mixed solution yield diverse topographies such as hemispheric clump, cylindrical rod, spherical walnut, micro/nano grass, micro/nano sheet, and fibrous network. And their crystal structures were mainly composed of Ti(HPO4)2·0.5H2O, (TiO)2P2O7, H2TiP2O8, Ti(HPO4)2 and TiO2. The morphology and crystal shape of the TiP coatings depend strongly on the mass ratio of H2O2/H3PO4, reaction temperature and water content. Besides, the formation mechanism of TiP coatings with diverse morphologies was explored from the perspective of energetics and crystallography. The mechanism exploration paved the way for custom-making TiP coatings with desirable micro/nanoscaled morphologies to meet specific application purposes. The in vitro cytological performances of TiP coatings were also evaluated by co-culturing with rat bone marrow stromal cells (BMSCs), demonstrating a positive prospect for their use in bone tissue engineering.

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The custom making of hierarchical micro/nanoscaled titanium phosphate coatings and their formation mechanism analysis

Bioinspired Fabrication of Calcium-Doped TiP Coating with Nanofibrous Microstructure to Accelerate Osseointegration.

Surface modification of new innocuous Ti–Mo–Zr based alloys for biomedical applications

In this study, nano-hydroxyapatite/polyamide66 composite scaffold was prepared by combining thermally induced phase separation and particulate leaching. The morphological structure and compositiona...

https://journals.sagepub.com/doi/pdf/10.1177/0883911518809387

Nano-hydroxyapatite/polyamide66 composite scaffold conducting osteogenesis to repair mandible defect:

https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73cbf567dfe070bec3566/original/3d-printed-multi-functional-ti6al4v-based-hybrid-scaffold-for-the-management-of-osteosarcoma.pdf

Bianyun Cai

Papers

The custom making of hierarchical micro/nanoscaled titanium phosphate coatings and their formation mechanism analysis

Bioinspired Fabrication of Calcium-Doped TiP Coating with Nanofibrous Microstructure to Accelerate Osseointegration.

Surface modification of new innocuous Ti–Mo–Zr based alloys for biomedical applications

Nano-hydroxyapatite/polyamide66 composite scaffold conducting osteogenesis to repair mandible defect:

3D Printed Multifunctional Ti6Al4V-Based Hybrid Scaffold for the Management of Osteosarcoma.