title: Injectable nanocomposites of single-walled carbon nanotubes and biodegradable polymers for bone tissue engineering.
abstract: We have investigated the dispersion of single-walled carbon nanotubes (SWNTs) and functionalized SWNTs (F-SWNTs) in the unsaturated, biodegradable polymer poly(propylene fumarate) (PPF) and examined the rheological properties of un-cross-linked nanocomposite formulations as well as the electrical and mechanical properties of cross-linked nanocomposites. F-SWNTs were produced from individual SWNTs by a diazonium-based method and dispersed better than unmodified SWNTs in both un-cross-linked and cross-linked PPF matrix. Cross-linked nanocomposites with F-SWNTs were superior to those with unmodified SWNTs in terms of their mechanical properties. Specifically, nanocomposites with 0.1 wt % F-SWNTs loading resulted in a 3-fold increase in both compressive modulus and flexural modulus and a 2-fold increase in both compressive offset yield strength and flexural strength when compared to pure PPF networks, whereas the use of 0.1 wt % SWNTs gained less than 37% mechanical reinforcement. These extraordinary mechanical enhancements considered together with Raman scattering and sol fraction measurements indicate strong SWNT-PPF interactions and increased cross-linking densities resulting in effective load transfer. With enhanced mechanical properties and capabilities of in situ injection and cross-linking, these SWNT/polymer nanocomposites hold significant implications for the fabrication of bone tissue engineering scaffolds.
authors.affiliation: Department of Bioengineering, Rice University, MS-142, Houston, Texas 77251-1892, USA.
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Shi
authors.forename: Jared L
authors.initials: JL
authors.lastname: Hudson
authors.forename: Patrick P
authors.initials: PP
authors.lastname: Spicer
authors.forename: James M
authors.initials: JM
authors.lastname: Tour
authors.forename: Ramanan
authors.initials: R
authors.lastname: Krishnamoorti
authors.forename: Antonios G
authors.initials: AG
authors.lastname: Mikos
mesh_terms: D001672:Biocompatible Materials / Q000008:administration & dosage / Q000737:chemistry; D001842:Bone and Bones / Q000737:chemistry / Q000378:metabolism; D003188:Composite Resins / Q000008:administration & dosage / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D004553:Electric Conductivity; D007267:Injections; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D011108:Polymers / Q000737:chemistry*; D012212:Rheology; D013059:Spectrum Analysis, Raman; D013696:Temperature; D023822:Tissue Engineering / Q000295:instrumentation* / Q000379:methods*; D014783:Viscosity
chemical_list: D001672:Biocompatible Materials; D003188:Composite Resins; D003432:Cross-Linking Reagents; D037742:Nanotubes, Carbon; D011108:Polymers