by Keyword: Titanium scaffold

Vidal, E, Guillem-Marti, J, Ginebra, MP, Combes, C, Ruperez, E, Rodriguez, D, (2021). Multifunctional homogeneous calcium phosphate coatings: Toward antibacterial and cell adhesive titanium scaffolds Surface & Coatings Technology 405, 126557

Implants for orthopedic applications need to be biocompatible and bioactive, with mechanical properties similar to those of surrounding natural bone. Given this scenario titanium (Ti) scaffolds obtained by Direct Ink Writing technique offer the opportunity to manufacture customized structures with controlled porosity and mechanical properties. Considering that 3D Ti scaffolds have a significant surface area, it is necessary to develop strategies against the initial bacterial adhesion in order to prevent infection in the early stages of the implantation, while promoting cell adhesion to the scaffold. The challenge is not only achieving a balance between antibacterial activity and osseointegration, it is also to develop a homogeneous coating on the inner and outer surface of the scaffold. The purpose of this work was the development of a single-step electrodeposition process in order to uniformly cover Ti scaffolds with a layer of calcium phosphate (CaP) loaded with chlorhexidine digluconate (CHX). Scaffold characterization was assessed by scanning electron microscopy, Energy dispersive X-ray spectroscopy, X-ray diffraction, micro-Raman microscopy and compressive strength tests. Results determined that the surface of scaffolds was covered by plate-like and whisker-like calcium phosphate crystals, which main phases were octacalcium phosphate and brushite. Biological tests showed that the as-coated scaffolds reduced bacteria adhesion (73 +/- 3% for Staphylococcus aureus and 70 +/- 2% for Escherichia coli). In vitro cell studies and confocal analysis revealed the adhesion and spreading of osteoblast-like SaOS-2 on coated surfaces. Therefore, the proposed strategy can be a potential candidate in bone replacing surgeries.

JTD Keywords: Antibacterial, Bacterial, Behavior, Biocompatibility, Calcium phosphate coating, Chlorhexidine, Chlorhexidine digluconate, Deposition, Electrodeposition, Hydroxyapatite coatings, Implants, One-step pulse electrodeposition, Plasma-spray, Release, Surface, Titanium scaffolds

Vidal, E., Torres, D., Guillem-Marti, J., Scionti, G., Manero, J. M., Ginebra, M. P., Rodríguez, D., Rupérez, E., (2020). Titanium scaffolds by direct ink writing: Fabrication and functionalization to guide osteoblast behavior Metals 10, (9), 1156

Titanium (Ti) and Ti alloys have been used for decades for bone prostheses due to its mechanical reliability and good biocompatibility. However, the high stiffness of Ti implants and the lack of bioactivity are pending issues that should be improved to minimize implant failure. The stress shielding effect, a result of the stiffness mismatch between titanium and bone, can be reduced by introducing a tailored structural porosity in the implant. In this work, porous titanium structures were produced by direct ink writing (DIW), using a new Ti ink formulation containing a thermosensitive hydrogel. A thermal treatment was optimized to ensure the complete elimination of the binder before the sintering process, in order to avoid contamination of the titanium structures. The samples were sintered in argon atmosphere at 1200 °C, 1300 °C or 1400 °C, resulting in total porosities ranging between 72.3% and 77.7%. A correlation was found between the total porosity and the elastic modulus of the scaffolds. The stiffness and yield strength were similar to those of cancellous bone. The functionalization of the scaffold surface with a cell adhesion fibronectin recombinant fragment resulted in enhanced adhesion and spreading of osteoblastic-like cells, together with increased alkaline phosphatase expression and mineralization.

JTD Keywords: Direct ink writing, Osseointegration, Recombinant protein, Thermoresponsive binder, Titanium, Titanium scaffold