CHAPTER 4
 CONTACT GUIDANCE OF ENDOTHELIAL CELLS


 Introduction

 In the previous chapters of this thesis, the principles of contact guidance and the

materials used for this study have been detailed. The final step of this project was to

examine the contact guidance phenomenon on a novel system to determine the effects of

elastic modulus on a surface's ability to direct cell growth. Contact guidance was

quantified on a group of silicone elastomers with elastic modulus values varying almost

800% but with similar surface energies. Textured surfaces made from four elastomer

formulations were seeded with porcine vascular endothelial cells (PVECs). Cell nuclei

were imaged and the nuclear shape was compared for surfaces of varying ridge

dimension, groove depth, and material modulus.


 Materials

Elastomer Substrates

 As described in the previous chapter, the unmodified base elastomer is the

Silastic T-2 Silicone Moldmaking Rubber produced by Dow Corning. Three vinyl

terminated PDMS based oligomers were included to give the elastic modulus a range

from 0.3 MPa to 2.3 MPa. Pertinent information about the elastomer systems, including

modulus and surface free energy, Ys, is listed in Table 4.1. The vinyl-terminated

oligomers were selected over non-functionalized oils due to their incorporation into the

network structure and to minimize additive release.