When culturing cells on flexible surfaces, it is important to consider extracellular matrix treatments that will remain on the surface under mechanical strain. Here we investigate differences in laminin surfaces that were deposited on oxidized PDMS (plasma only) versus oxidized PDMS treated with aminopropyltrimethoxysilane (silane-linked). We use scanning X-ray reflectivity (SXR), transmission electron microscopy (TEM), and immunofluorescence to probe the quantity and uniformity of the laminin on the treated PDMS surfaces. We test laminin retention under strain and vascular smooth muscle cell (VSMCs) viability and proliferation under static, equibiaxial strain, and mild non-equibiaxial strain. We found that there is a monolayer of laminin at coverage of around 45% for the plasma only and 50% for the silane-linked treatment as determined by SXR. TEM and immunofluorescence reveals additional islands of laminin aggregates for the plasma only PDMS as compared to the relatively smooth and uniform silane-linked laminin surface. Equibiaxial stretching of the PDMS surfaces shows greatly improved retention of the silane-linked laminin. Static cultures VSMCs on laminin reveals no difference in cell proliferation between the laminin on the plasma only and silane-linked surfaces at 3 d. However, there are significantly more cells on the silane-linked surface at 4 d of intermittent equibiaxial stretch. Under mild non-equibiaxial stretch, the cells from both surface treatments are viable and do align although the plasma only treatment still lags behind in cell count.
Citation: Biophysical Journal
Pub Type: Journals
fluorescence, laminin, polydimethylsiloxane, proliferation, protein, smooth muscle cells, specular X-ray reflectivity, transmission electron microscopy