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The impact of multimodal pore size considered independently from porosity on mechanical performance and osteogenic behaviour of titanium scaffolds

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journal contribution
posted on 14.05.2021, 10:36 by Carmen TorresCarmen Torres, Mattia Norrito, FR Almushref, Paul ConwayPaul Conway
Titanium porous scaffolds comprising multimodal pore ranges (i.e., uni-, bi-, tri-modal and random) were studied to evaluate the effect of pore size on osteoblastogenesis. The scaffolds were manufactured using spaceholder-powder metallurgy and porosity and pore size were kept independent. Their mechanical and physical properties (i.e., stiffness, strength, total and open porosity) were determined. In a first step, unimodal porous samples were tested with a mouse osteoblastic clonal cell line to ascertain pore size and porosity effects on cellular behaviour. Their proliferation (via cell number and total protein content), differentiation (via ALP enzyme levels) and maturation potency were investigated with gene markers (Runx2, osteocalcin and cytoplasmatic calcium). In a second step informed by the previous results, multimodal scaffolds were shortlisted according to a set of criteria that included a stiffness equivalent to that of cortical or trabecular bone, high strength and high open porosity. Their bioactivity performance was then studied to assess the synergistic effects of mixed pore ranges. The study concludes that pre-osteoblasts cultivated in unimodal microstructures with a pore range 106–212 μm of 36% total (actual) porosity and 300–500 μm of 55% total (actual) porosity achieved the largest extent of maturation. Bimodal microstructures comprising small (106–212 μm) and large (300–500 μm) pore ranges, distinctively distributed within the volume, and 40% (actual) porosity outperformed others, including multimodal (i.e. three or more pore ranges) and non-porous samples. They displayed a synergistic effect over the unimodal distributions. This should be a consideration in the design of scaffolds for implantation and bioengineering applications.

Funding

EPSRC DTP award ref. 2133136

Cultural Bureau of the Royal Embassy of Saudi Arabia in London (no. JU55)

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

Materials Science and Engineering: C

Volume

124

Issue

May

Publisher

Elsevier BV

Version

VoR (Version of Record)

Rights holder

© 2021 The Authors

Publisher statement

This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Acceptance date

03/03/2021

Publication date

2021-03-10

Copyright date

2021

ISSN

0928-4931

Language

en

Depositor

Dr Carmen Torres-Sanchez. Deposit date: 16 March 2021

Article number

112026