A biocompatible thermoset polymer binder for Direct Ink Writing of porous titanium scaffolds for bone tissue engineering

Abstract

There is increasing demand for synthetic bone scaffolds for bone tissue engineering as they can counter issues such as potential harvesting morbidity and restrictions in donor sites which hamper autologous bone grafts and also address the potential for disease transmission in the case of allografts. Due to their excellent biocompatibility, titanium scaffolds have great potential as bone graft substitutes as they can mimic the structure and properties of human cancellous bone. Here we report on a new thermoset bio-polymer which can act as a binder for Direct Ink Writing (DIW) of titanium artificial bone scaffolds. We demonstrate the use of the binder to manufacture porous titanium scaffolds with evenly distributed and highly interconnected pores ideal for orthopaedic applications. Due to their porous titanium structure, the scaffolds exhibit an effective Young's modulus similar to human cortical bone, alleviating undesirable stress-shielding effects, and possess superior strength. The biocompatibility of the scaffolds was investigated in vitro by cell viability and proliferation assays using human bone-marrow-derived Mesenchymal stem cells (hMSCs). The hMSCs displayed well-spread morphologies, well-organised F-actin and large vinculin complexes confirming their excellent biocompatibility. The vinculin regions had significantly larger Focal Adhesion (FA) area and equivalent FA numbers compared to that of tissue culture plate (TCP) controls, showing that the scaffolds can support cell viability and promote attachment. In conclusion, we have demonstrated the excellent potential of thermoset bio-polymer as a Direct Ink Writing ready inkjet binder for manufacture of porous titanium scaffolds for hard tissue engineering.

Tuning the 3D Printability and Thermomechanical Properties of Radiation Shields

“…Additionally, these extrusion methods also allow for numerous hardening regimes such as UV curing, elevated temperature curing, freeze drying, and other means, which increases the possible range of new materials that can be 3D printed. Examples include aerogels and foams developed from ceramics and carbonaceous materials [20][21][22][23], synthetic bone and osteoinduction scaffolds [24][25][26][27], smart magnetoresponsive devices [28][29][30], and more. Thus, DIW lends itself to immense materials development exploration and can result in a variety of specialty parts for many applications.…”

Titanium Scaffolds by Direct Ink Writing: Fabrication and Functionalization to Guide Osteoblast Behavior

“…The presence of undesirable residual particles may also increase the risk of adverse inflammatory responses. Additionally, these technologies generate the waste of used powder that must be recycled [19].…”

Additive manufacturing of composites made of epoxy resin with magnetite particles fabricated with the direct ink writing technique

“…18 The upper and lower limit values of compression strength of the materials used in the fabrication of the composite were for the epoxy resin 45 MPa and 89.6 MPa. 8 Then s m ¼ 89.6 MPa.…”

“…DIW is an extrusion based-technique in which particularly short fibers and particles can be easily adapted for the manufacturing process. Among many of the case studies with DIW process, printing composite materials are biocompatible thermoset polymers with titanium particles with similar properties to the human bones, 8 epoxy composites with graphite nanoplatelets, 9 clays with ceramic particles. 10 DIW technique has also been adapted for the fabrication of colloidal suspension in low-viscosity composites.…”