Fabrication of porous ultra-short single-walled carbon nanotube nanocomposite scaffolds for bone tissue engineering

Abstract

We investigated the fabrication of highly porous scaffolds made of three different materials [poly(propylene fumarate) (PPF) polymer, an ultra-short single-walled carbon nanotube (US-tube) nanocomposite, and a dodecylated US-tube (F-US-tube) nanocomposite] in order to evaluate the effects of material composition and porosity on scaffold pore structure, mechanical properties, and marrow stromal cell culture. All scaffolds were produced by a thermal-crosslinking particulate-leaching technique at specific porogen contents of 75, 80, 85, and 90 vol%. Scanning electron microcopy, microcomputed tomography, and mercury intrusion porosimetry were used to analyze the pore structures of scaffolds. The porogen content was found to dictate the porosity of scaffolds. There was no significant difference in porosity, pore size, and interconnectivity among the different materials for the same porogen fraction. Nearly 100% of the pore volume was interconnected through 20microm or larger connections for all scaffolds. While interconnectivity through larger connections improved with higher porosity, compressive mechanical properties of scaffolds declined at the same time. However, the compressive modulus, offset yield strength, and compressive strength of F-US-tube nanocomposites were higher than or similar to the corresponding properties for the PPF polymer and US-tube nanocomposites for all the porosities examined. As for in vitro osteoconductivity, marrow stromal cells demonstrated equally good cell attachment and proliferation on all scaffolds made of different materials at each porosity. These results indicate that functionalized ultra-short single-walled carbon nanotube nanocomposite scaffolds with tunable porosity and mechanical properties hold great promise for bone tissue engineering applications.

Lithograph-moulded poly-L-co-D,L lactide porous membranes for osteoblastic culture

“…Pore quality and quantity do not influence the proliferation of osteogenic cells from rat calvaria cultivated on PLGA (75:25) for different periods of time 48 . Thus, as other studies have demonstrated, the interaction between osteoblasts and materials with variable porosities and pore sizes does not affect the cellular response 49,50 . Consequently, different cell types respond differently to the substrate surface topography 11 .…”

Synchrotron Radiation and Nanotechnology for Stem Cell Research

“…Many researchers have tried to define which properties are required for the optimal synthetic scaffold, in particular for bone tissue replacement (Hutmacher, 2000). Ideally, scaffolds should possess adequate mechanical strength and permeability (van Lenthe et al, 2007), high porosity (Shi et al, 2007), large surface area to volume ratio, as well as biocompatibility and non-toxicity (Murugan & Ramakrishna, 2006). Moreover, pore interconnectivity is an important scaffold criterion (Moore et al, 2004) which influences nutrient supply (Hui et al, 1996), circulation of extracellular material (Gross & RodriguezLorenzo, 2004), the contact between adjacent cells (Darling & Sun, 2004), and the promotion of blood vessel and bone tissue ingrowth (Kuboki et al, 1998).…”

Preparation and Properties of Sweat-gland Type High Temperature Self-lubricating Metal Ceramic Preform

“…However, in the process of high-temperature sintering, the solid lubricant is easy to be oxidated ,which will cause loss to its lubricating properties; at the same time, the uneven distribution of solid lubricant and the damage to continuity of matrix will significantly reduce the strength, toughness and wear resistance of composite. Based on the structure of sweat-gland, the high temperature self-lubrication micro-porous materials are prepared by infiltrating solid lubricants into micro-porous metal ceramic preforms, which can effectively realize self-lubricating under some special conditions.The material has become an area of "intense research" [2][3].…”