the material was ablated by the plasma. Cracks on the order of 0.5-1.5 [im were seen to

form after mechanical manipulation of treated surfaces. This phenomenon seems to be a

result of the cracking of a hard silica-like layer on the surface.[116] Due to the

uncertainties with the feature dimensions and surface mechanical properties, fibronectin

adsorbed surfaces were used for the main analysis of the effects of contact guidance.

Contact Guidance on Textured Elastomers

 Contact guidance of PVECs on textured silicone elastomers was measured by the

nuclear form factor, in which the log of the ratio of nuclear length to width was

presented. Results demonstrated that as the ridge width decreased from 20 .im to 5 .im

contact guidance increased, as well as when the depth of the grooves increased from 1.5

lm to 5 rm. Data analysis showed that the groove depth was the most important factor

in nuclear alignment. Average values of the nuclear form factor for 5 [im deep, 5 [im

wide samples exceeded 0.3, which implies the length was more than twice the width on

average. Shallower grooves increased the length of the nuclei by approximately 25% in

comparison to the width.

 Contact guidance on fibronectin-coated elastomers was examined to determine

the effect of modulus. It was expected that higher modulus materials would increase the

effect of contact guidance. Elastic modulus on 4 elastomers was measured by tensile

tests and resulted in a range of values from 0.3 MPa to 2.34 MPa. There was no

significant difference in the contact guidance on the deep 5 [m grooves with varying

modulus. The 1.5 rm deep grooves showed a significant increase in the alignment of

cells to the groove in the highest modulus material compared to the lowest modulus

material for the 5 rm and 10 rm wide ridges. The conclusion to be taken from this data

is that modulus does seem to play a role in the determination of contact guidance, but