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Plasma Enhanced Chemical Vapor Deposited Poly (2-hydroxyethyl methacrylate) for Fabricating a Degradable, Biocompatible Intestinal Tissue Culture Substrate

Courtney A. Pfluger, Chemical Engineering, Northeastern University, 342 Snell Engineering Center, Boston, MA 02115, Rebecca L. Carrier, Department of Chemical Engineering, Northeastern University, 342 Snell Engineering Center, 360 Huntington Avenue, Boston, MA 02115, and Daniel D. Burkey, Northeastern University, 342 Snell Engineering Center, 360 Huntington Avenue, Boston, MA 02115.

It has been shown that, in the study of oral drug transport, epithelial cells cultured on a chemically biomimetic substrate more accurately reflect in vivo cellular behavior [1,2]. It is expected that biomimetic nano- and micro-topology will also influence intestinal epithelial cell phenotype, and specifically the expression of proteins important to drug uptake and metabolism, because these proteins are expressed differentially along the villus-crypt axis of the intestinal basement membrane in vivo [3]. To test this hypothesis, we are fabricating biomimetic molds of sections of the small intestine and examining the attachment, migration and protein expression of intestinal epithelial cells on the biomimetic scaffold.

The topology of the intestinal basement membrane was replicated using a plasma CVD technique to create a film with micron scale thickness and with micro- and nano-meter scale features on a section of pig intestine to be ultimately used as a cell culture scaffold. The biodegradable polymer deposited was poly(2-hydroxyethyl methacrylate) (pHEMA). pHEMA's porosity can be controlled by adjusting the degree of cross-linking, making it ideal for drug transport studies and as a material for tissue scaffolds [4]. FT-IR analysis confirmed the existence of key functional groups in poly(2-hydroxyethyl methacrylate) after plasma deposition. Carbonyl peak intensity confirmed film cross-linking at varying degrees. Cross-linking density affected the degree of swelling and extent of degradation of the film over time.

Analysis of cell attachment, growth, and metabolic activity demonstrated substrate biocompatibility for intestinal epithelial cell culture. Comparisons of cell attachment on CVD cross-linked pHEMA verses other culture substrates such as collagen, PDMS (alone and coated with fibronectin), and glass were performed. Cells adhered to high cross-linked pHEMA just as well as collagen, polystyrene and PDMS coated with fibronectin and better than to glass and PDMS alone. This confirms that cross-linked pHEMA can be used as a scaffold with the same cell adhesion properties as polystyrene, collagen, and PDMS. CVD pHEMA offers the advantage over these materials of forming conformal films with biomimetic topography in a dry, one step process.

In summary, we have demonstrated a plasma CVD process for fabricating a biocompatible pHEMA polymer film suitable for cell culture and demonstrated that we can alter its properties via variable cross-linking. We have shown that cross-linked pHEMA can be deposited onto the intestinal basement surface and retain micro- and nano- scale topological features. The next step will be to use the cross-linked pHEMA conformal, biomimetic scaffold for cell culture and protein expression experiments, and compare resulting cultures to those on flat cell culture substrates.

1. P. Artursson, Critical Reviews in Therapeutic Drug Carrier Systems 1991, 8(4), 305-330.

2. B. H. Stewart, O. H. Chan, N. Jezyk, D. Fleisher, Advanced Drug Delivery Reviews 1997, 23(1 3), 27-45.

3. N. Cigna, C. Nicoleeti, A. Durand, J. C. Chaix, T. Giardina, J. Perrier, Cell Biology International 2007, 31, 966-973.

4. H. G. Pryce Lewis, K.K.S. Lau, Y. Mao, K.K. Gleason, Annual Technical Conference Proceedings - Society of Vacuum Coaters 2005, 48th, 90-94.