AVS 51st International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI1-WeM

Paper BI1-WeM11
Evaluation of PDMS as a Model Substrate to Investigate Effects of Substrate Compliance on Cell Behavior: Interplay of Surface Chemistry and Substrate Mechanics

Wednesday, November 17, 2004, 11:40 am, Room 210D

Session: Cell-Surface Interactions
Presenter: X.Q. Brown, Boston University
Authors: X.Q. Brown, Boston University
J.Y. Wong, Boston University
Correspondent: Click to Email
Polydimethylsiloxane (PDMS) is an attractive model system for studying the effects of tissue mechanical properties on cell behavior, because the elastic modulus of PDMS can be tuned to achieve a physiologically-relevant range. However, it has been suggested that altering crosslink density can also modulate surface properties. Both the chemical and mechanical properties of a substrate can affect cell behavior: while the importance of surface chemistry and substrate mechanics have been studied independent of each other, few studies have considered their integrated effects. In this study, we characterized the mechanical and surface properties of PDMS substrata with different crosslink density and systematically investigated the effect of PDMS crosslink density on vascular smooth muscle cell (VSMC) attachment, spreading and proliferation. We find that after the same surface treatment, the water contact angle of PDMS decreases with decreased crosslink density, whereas the amount of protein adsorbed onto the material surface remains the same. We also find that in the absence of serum, there is a 39% decrease in cell attachment and a 42% decrease in projected cell area as the Youngâ?Ts modulus decreases from 1.79 to 0.05 MPa. Although these differences in VSMC adhesion are diminished in the presence of serum or adsorbed fibronectin, the rate of serum-stimulated cell proliferation is significantly lower on PDMS with higher crosslink density. We conclude that for the range of crosslink density we investigated, the surface properties of PDMS play a major role in controlling the initial attachment and spreading of VSMC, whereas the mechanical properties of PDMS influence the long term growth of VSMC.