Paper BI-TuP2
In Vitro Cytotoxicity of Poly(N-isopropyl acrylamide)

Tuesday, October 30, 2012, 6:00 pm, Room Central Hall

Poly(N-isopropyl acrylamide) (pNIPAM) is a thermoresponsive polymer that undergoes a conformation change in a physiologically relevant temperature range. Above its lower critical solution temperature (LCST, ~32^oC), pNIPAM is relatively hydrophobic, and cells can be easily cultured on pNIPAM-grafted surfaces. When the temperature is lowered, the polymer’s chains extend and cells detach in intact sheets. It has previously been demonstrated that the NIPAM monomer is toxic; however, there are conflicting opinions as to whether the polymerized form of NIPAM is toxic. Since the cell sheets detached from pNIPAM could ultimately be used on humans, it is crucial to assess the cytotoxicity of surfaces coated with pNIPAM. Very few (<10) studies exist that investigate the cytotoxicity of pNIPAM, and their results are conflicting. Furthermore, the published studies are not comprehensive. Instead, they focus on isolated cell lines cultured on pNIPAM films generated using different methods, and use different assays to determine the degree of cytotoxicity. In this work, we present a comprehensive investigation of the cytotoxicity of pNIPAM-grafted surfaces. The cytotoxicity of pNIPAM is evaluated using different cell lines (endothelial, epithelial, smooth muscle, and fibroblasts), polymerization (free radical and commercially available pNIPAM) and deposition (spin coating and plasma polymerization) techniques, and cytotoxicity tests (MTS, Live/Dead, plating efficiency). The pNIPAM-coated surfaces are evaluated using X-ray photoelectron spectroscopy and goniometry. We find that there is lower cell viability on pNIPAM surfaces when compared to controls. The viability also seems to be deposition type dependent. 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.