Porosity and pore size effect on the properties of sintered Ti35Nb4Sn alloy scaffolds and their suitability for tissue engineering applications

Abstract

Porous scaffolds manufactured via powder metallurgy and sintering were designed for their structure (i.e. pore size and porosity) and mechanical properties (stiffness, strength) to be controlled and tailored to mimic those of human bone. The scaffolds were realised to fulfil three main objectives: (i) to obtain values of stiffness and strength similar to those of trabecular (or spongy) bone, with a view of exploiting these as bone grafts that permit cell regeneration, (ii) to establish a relationship between stiffness, strength and density that allows tailoring for mass customisation to suit patient's needs; and (iii) to assess alloy cytotoxicity and biocompatibility via in vitro studies. The results obtained using a very low stiffness alloy (Ti35Nb4Sn) further lowered with the introduction of nominal porosity (30-70%) with pores in the ranges 180-300 µm and 300-500 µm showed compatibility for anatomical locations typically subjected to implantation and bone grafting (femoral head and proximal tibia). The regression fitting parameters for the linear and power law regressions were similar to those found for bone specimens, confirming a structure favourable to capillary network formation. Biological tests confirmed non-cytotoxicicity of the alloy. Scaffolds of porosity nominal 50%vol and pore range 300-500 µm performed best in the adhesion and propagation assays due to a good balance between surface area and pore cavity volume.

Permeability and fluid flow-induced wall shear stress in bone scaffolds with TPMS and lattice architectures: A CFD analysis

“…In the design of bone scaffolds, the common goal in general is to mimic the structure of the trabecular (cancellous or spongy) bone [30] found in the human body. The trabecular bone has a greatly porous structure, accordingly, the design of high porosity scaffolds is the main criterion in bone tissue engineering.…”

A massively multi-scale approach to characterizing tissue architecture by synchrotron micro-CT applied to the human placenta

“…Porosity within human tissues has been extensively investigated in bone and other soft tissues (e.g. adipose tissue) from the perspective of tissue engineering [35][36][37][38]. Nonetheless, the placental maternal IVS porous medium has been less well studied.…”

A Critical Review on Polymeric Biomaterials for Biomedical Applications

“…The ideal pore size required for skin and bone tissue engineering varies. From the earlier studies, it was found that the pore size ranging from 200 to 400 µm was suitable for bone tissue engineering [ 51 ], whereas the pores ranging from 50 to 200 µm were found to be effective in the smooth muscles and soft tissue engineering process [ 52 , 53 , 54 ]. Natural and synthetic polymers-based sponges have been studied for their potential biomedical applications.…”