A Polyelectrolyte Multilayer Thin Film System for Cell Adhesion, Gene Delivery and Inductive Tissue Engineering Applications

Download or read book A Polyelectrolyte Multilayer Thin Film System for Cell Adhesion, Gene Delivery and Inductive Tissue Engineering Applications written by Christina Holmes and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "In order for the vast therapeutic potential of tissue engineering to be realized, inductive three-dimensional (3D) scaffolds that can direct cell behaviour and tissue architecture must be developed. Although a variety of strategies which enable scaffold-based biofactor release are under investigation, the processing conditions typically employed restrict the system architectures and mechanical properties that can be produced.The main objective of this thesis work was to develop an inductive tissue engineering system for in situ 3D gene delivery, utilizing the layer-by-layer deposition technique and a model scaffold. Towards that end, a novel polyelectrolyte multilayer film system composed of glycol-modified chitosan (Glyc-CHI) and hyaluronic acid (HA) was developed and analyzed. This biocompatible Glyc-CHI/HA multilayer system was then modified to incorporate gene delivery lipoplexes, composed of plasmid DNA complexed with Lipofectamine2000TM, in order to facilitate in vitro delivery of a marker gene encoding enhanced green fluorescent protein (EGFP). The system, with and without incoporated gene delivery lipoplexes, was then adapted to be used as a LbL coating on a 3D model porous scaffold system microfabricated from poly(lactic-co-glycolic acid) (PLGA). The polyelectrolyte multilayer film system developed in this study exhibited a number of novel and useful features. Glyc-CHI/HA films composed of 5 or more bilayers were displayed significantly increased in vitro cellular adhesion, growth and viability compared to corresponding films consisting of the well characterized unmodified chitosan/HA system, while maintaining many similar physical properties. Meanwhile, multilayers incorporating gene delivery lipoplexes achieved in vitro transfection efficiencies of up to 20% in NIH3T3 and HEK293 cells, and were able to maintain transfection for at least 7 days. PLGA scaffolds LbL-coated with these Glyc-CHI/HA films supported in vitro MC3T3 cell growth and viability for a period of at least 2 weeks at levels similar to, or better than, those achieved in uncoated control scaffolds. A novel imaging technique known as optical coherence phase microscopy (OCPM) was demonstrated to enable in situ, non-invasive, label-free imaging of tissue structure and viability within our 3D tissue engineering scaffolds. Finally, coated PLGA scaffolds incorporating gene delivery lipoplexes were found to support scaffold-based in vitro transfection of HEK293 cells at levels significantly higher than uncoated scaffolds with surface adsorbed lipoplexes. Overall, this thesis work thus serves as an important first step towards using Glyc-CHI/HA multilayer films for controlled delivery of various therapeutic genes in 2D and 3D inductive tissue engineering applications." --