| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2014) | |
| Biomaterial Interfaces | Wednesday Sessions |
| Session BI-WeM |
| Session: | Biomaterials, Interfaces, and Cells |
| Presenter: | Elena Liang, University of California, Irvine |
| Authors: | E. Liang, University of California, Irvine MN. Dickson, University of California, Irvine N. Vollereaux, University of California, Irvine AF. Yee, University of California, Irvine |
| Correspondent: | Click to Email |
Understanding cell interactions with material surfaces is critical to the performance of medical devices. Of particular interest to our research, such understanding could lead to simple and durable ways to control cell adhesion without chemically modifying the surface of biomaterials used in implantable devices. Recently, it was found that the nanopillar structures on cicada wings are inherently antibacterial irrespective of surface chemistry (Ivanova et al. Small. 2012). Such nanostructures can eventually be incorporated on surfaces of medical devices, but first, we need to ensure that patient’s own cells would not be adversely affected by these structures. Hu et al. showed that nanopillars of widely varying aspect ratios and surface energies had strong effects on cell morphology, discouraging cell spreading (Hu et al. 2010). Kong et al. discovered that human embryonic stem cells grown on nanopillar structures have a significantly reduced number of focal adhesions per cell and concordantly exhibit increased cell motility on the nanopillars (Kong et al. 2013). Based on these findings, we hypothesized that the pillar nanostructures on the cicada wing would prevent cells from adhering. To show this, we first created a library of nanostructures, beginning with a biomimetic cicada wing replicate. We molded a negative hPDMS stamp of the cicada wing and pressed the stamp into polymethylmethacrylate and polystyrene films to create the polymer replicates. We also fabricated pillar arrays of different spacings from commercially available silicon molds using nanoimprint lithography. To evaluate cell adhesion, we counted the number of fibroblasts adhering to flat polymer and the nanopillars, and we determined the number of focal adhesion sites from immunostaining for vinculin, a major protein in the focal adhesion complex. In addition, we examined cell morphology on the various surfaces. After 24 hours, we observed that the cells adopted different cell morphologies, possibly indicating changes in adhesion dynamics. Fibroblasts showed a spread-like morphology on the flat film while the cells on pillars were more equiaxed. Our study has shown that nanostructures in the 100-500 nm-size range do affect cell adhesion dynamics. We found that structure dimensions modulate the adhesion of cells, which may provide researchers a useful means of controlling cell adhesion on material surfaces.