Presenter: Seth D. McCullen
Advisor(s): Russell E. Gorga
Author(s): Seth D. McCullen, Russell E. Gorga, & Elizabeth G. Loboa
Graduate Program: Biomedical/Textile Engineering, Textile Engineering, Biomedical Engineering

Title: Production of an electrically conductive tissue scaffold for human mesenchymal stem cells

Abstract: Tissue engineering is an emerging discipline, where life sciences and engineering intertwine with the end goal of creating fully-functional organs for human transplant. Our research focuses on the creation of advanced tissue scaffolds to provide a functional three dimensional interface substrate, with enhanced properties to direct human mesenchymal stem cells (hMSC) down the osteogenic lineage. The tissue scaffolds are nanocomposites incorporating multi-walled carbon nanotubes (MWNT) into polymeric matrices of polyethylene oxide and collagen. Tissue scaffolds were developed through the electrospinning process, which creates a construct of high permeability and proper mechanical integrity similar to the scale of the extra-cellular matrix of cells. Tissue scaffold fabrication was optimized by varying levels of MWNT and the dispersing agent gum arabic in aqueous solutions of the indicated polymers. Various ratios of MWNT and gum arabic concentrations were sonicated to break apart the van der waals forces agglomerating the MWNT, affording homogeneous dispersions in aqueous solutions without MWNT functionalization. The parameters of the electrospinning process were optimized through investigation of the rheological behavior of composite solutions and SEM analysis of the fabricated scaffolds.

Characterization of the tissue scaffolds included image analysis, tensile tests, and conductivity measurements to demonstrate enhanced properties and preferred morphologies. With increased loading levels of MWNT, the mechanical and electrical properties of the composites increased significantly when compared to the neat polymeric scaffolds. The composite tissue scaffolds were also implemented in viability studies with hMSC’s. 

Future work will focus on the use of the scaffolds in functional tissue engineering scenarios, with the application of pulsed electromagnetic fields (PEMF) across the fabricated scaffolds. Past research efforts has indicated that PEMF’s are able to increase cellular proliferation and to further drive the development of cells into anatomically correct three-dimensional structures.