| AVS 60th International Symposium and Exhibition | |
| Biomaterial Interfaces | Wednesday Sessions |
| Session BI-WeM |
| Session: | Cell-Surface Interactions |
| Presenter: | M.A. Cooperstein, University of New Mexico |
| Authors: | M.A. Cooperstein, University of New Mexico H.E. Canavan, University of New Mexico |
| Correspondent: | Click to Email |
Poly(N-isopropyl acrylamide) (pNIPAM) undergoes a conformation change in a physiologically relevant temperature range. PNIPAM is relatively hydrophobic above its lower critical solution temperature (LCST, ~32oC), and mammalian cells are easily cultured on pNIPAM-grafted surfaces. When the temperature is lowered below the LCST, the polymer’s chains rapidly hydrate, and cells detach as intact sheets capable of being used to engineer tissues (“cell sheet engineering”). Although the NIPAM monomer is toxic, there are conflicting reports as to whether its polymerized form is toxic, as well. Very few (<10) studies exist that investigate the cytotoxicity of pNIPAM, and their results are conflicting. Furthermore, the published studies are not comprehensive. Before the cell sheets detached from pNIPAM can ultimately be used on humans, it is crucial to first assess the cytotoxicity of the surfaces from which they have been obtained. In this work, we present a comprehensive investigation of the cytotoxicity of pNIPAM-grafted surfaces. The relative biocompatibility of substrates prepared using different polymerization (free radical and plasma polymerization) and deposition (spin coating and plasma polymerization) techniques is evaluated using appropriate cytotoxicity tests (MTS, Live/Dead, plating efficiency). Four different mammalian cell types (endothelial, epithelial, smooth muscle, and fibroblasts) were used for the cytotoxicity testing. The pNIPAM-coated surfaces were evaluated for their thermoresponse and surface chemistry using X-ray photoelectron spectroscopy and goniometry. We find that while cell viability on pNIPAM surfaces decreases when compared to controls, the viability also seems to be deposition type dependent, with sol-gel-based pNIPAM surfaces being the least biocompatible. We attribute this difference to surface topography and chemistry. This work will have valuable insights into the cytotoxicity of pNIPAM-coated surfaces, and therefore into the applicability of cells grown on these surfaces for use in human subjects. In addition, the trends observed in the effect of polymer molecular weight, surface modification technique, and cell type may be extrapolated to other bioactive polymers of interest.