Radiofrequency glow discharge treatment

 To improve the wettability of the substrate, surfaces were exposed to an argon

RFGD plasma treatment. The plasma system used was a RF Plasma Inc. HFS 401S

instrument, set at 50 W. Four samples in a polystyrene petri dish were treated at a time,

approximately 5.5 cm from the bottom of the plasma RF coils, and after the samples were

in place, the plasma chamber was evacuated for 10 minutes. Pressure in the plasma

chamber got as low as 10 mTorr before treatment and typically around 25 mTorr

immediately after the plasma was switched on. The argon gas was introduced at a flow

rate of 200 sccm and the RFGD treatment was activated for 5 minutes. After treatment,

the pressure was equalized in the chamber with ambient air.

Fibronectin adsorption

 Fibronectin adsorption on microtextured elastomer samples was performed via the

method of Ostuni and Whitesides.[64] Lyophilized bovine plasma fibronectin was

received from Sigma and the contents were dissolved in 2 mL of 0.22 [m filtered water

at 37C for 45 minutes. The solution was diluted to 50 [g/mL in Hank's balanced salt

solution (BSS). Elastomer samples cut into 15 mm disks were sterilized with 70% EtOH

and rinsed 3X with BSS, then placed in 24-well culture plates and covered with 0.5 mL

of the fibronectin solution. To ensure that fibronectin displaced air trapped in textured

surfaces, the culture plate was exposed to house vacuum for 1 minute. During this time,

small bubbles formed on the surface in the same pattern as the texture. After these

bubbles detached, the vacuum was released and the fibronectin solution left on for 1 hour

at ambient conditions. Samples were then rinsed three times with BSS.