Intrinsic Osteoinductivity of Porous Titanium Scaffold for Bone Tissue Engineering

Abstract

Large bone defects and nonunions are serious complications that are caused by extensive trauma or tumour. As traditional therapies fail to repair these critical-sized defects, tissue engineering scaffolds can be used to regenerate the damaged tissue. Highly porous titanium scaffolds, produced by selective laser sintering with mechanical properties in range of trabecular bone (compressive strength 35 MPa and modulus 73 MPa), can be used in these orthopaedic applications, if a stable mechanical fixation is provided. Hydroxyapatite coatings are generally considered essential and/or beneficial for bone formation; however, debonding of the coatings is one of the main concerns. We hypothesised that the titanium scaffolds have an intrinsic potential to induce bone formation without the need for a hydroxyapatite coating. In this paper, titanium scaffolds coated with hydroxyapatite using electrochemical method were fabricated and osteoinductivity of coated and noncoated scaffolds was compared in vitro. Alizarin Red quantification confirmed osteogenesis independent of coating. Bone formation and ingrowth into the titanium scaffolds were evaluated in sheep stifle joints. The examinations after 3 months revealed 70% bone ingrowth into the scaffold confirming its osteoinductive capacity. It is shown that the developed titanium scaffold has an intrinsic capacity for bone formation and is a suitable scaffold for bone tissue engineering.

Additive manufactured metallic implants for orthopaedic applications

“…These scaffolds were then implanted in sheep femoral condyle. Extensive osteoinduction and osteointegration (70% bone ingrowth) were observed in vivo, confirming the intrinsic capacity of the produced porous titanium scaffolds for bone regeneration [47]. Therefore, the current evidence supports that additive manufacturing allows the fabrication of an implant with complex geometries matching to the patient's bony anatomy, and the combination of both porous scaffolds for osseointegration [48,49] and rigid parts for physiological load transfer [50] (Fig.…”

“…Hydroxyapatite (HA) coatings have been used to prompt osteogenesis without the need for additional osteogenic cells or bone morphogenic proteins (BMP) [45]. The results showed that HA coating to an AM porous titanium scaffold did not significantly increase osteogenicity in vitro and noncoated titanium scaffolds were also osteoinductive [47]. These scaffolds were then implanted in sheep femoral condyle.…”

Biomineralization improves mechanical and osteogenic properties of multilayer‐modified PLGA porous scaffolds

“…It is widely accepted that advanced tissue engineering of bone requires well designed scaffold systems with proper cell compatibility and osteoconductivity for beneficial adhesion, proliferation, and differentiation of osteoblast and progenitor cells along with sufficient mechanical strength to provide adequate structural support in vivo. 51,52 Within this context, biomineralization is a simple method which is believed to improve mechanical property and support osteogenesis, which is normally achieved by incubation of plain scaffolds in SBF or other preparations containing calcium and phosphate ions. 53 Here, we show for the first time that the prior coating of scaffolds with major organic components of bone, namely Col I and oCS by LbL technique provide superior conditions for deposition of HAP on PLGA scaffolds that acquire excellent mechanical and osteoconductive properties.…”

Synthesis of Silver-Coated Bioactive Nanocomposite Scaffolds Based on Grafted Beta-Glucan/Hydroxyapatite via Freeze-Drying Method: Anti-Microbial and Biocompatibility Evaluation for Bone Tissue Engineering

“…It was also found that mechanical strength of these scaffold samples and exhibited lower mechanical strength in wet environment due to release of Ag-particle into aqueous media [53,54]. Ag-coating has a vital role in improving the mechanical strength of BNS samples with suitable porosity for tissue engineering [55]. The polymeric matrix has a different chemical structure and impact over the grain boundary.…”