Paper BI-ThP1
Temperature Gradient Device for Investigation of Cell Detachment from Thermoresponsive Surfaces

Thursday, October 21, 2010, 6:00 pm, Room Southwest Exhibit Hall

Poly(N-isopropyl acrylamide) (pNIPAM) undergoes a phase change in a physiologically relevant temperature range that leads to cell release. Above its lower critical solution temperature (LCST, ~32^oC), pNIPAM is relatively hydrophobic, and when grafted to a surface, it takes on a packed conformation. There have been numerous studies on the conformation change of pNIPAM across its LCST. Although it is known how pNIPAM chains tethered to a substrate behave when the temperature is changed, no study has probed the influence of a temperature gradient on the behavior of cells attached to the polymer. In this work, we present the investigation of cell detachment from pNIPAM-grafted surfaces resting on a temperature-gradient device. The polymer was deposited on the surface using plasma polymerization. This deposition technique creates a conformal, sterile film that is compatible with any surface chemistry, including the transparent well plates required for these experiments. Prior to their use for cell culture, it is imperative to characterize the pNIPAM films for film thickness, surface chemistry, and thermoresponse, as the surface characteristics determine cell attachment and detachment. The characterization was performed via interferometry, X-ray photoelectron spectroscopy (XPS), and contact angle measurements. Using a device fabricated in our laboratory, we studied whether there is a gradual progression of cellular detachment from the polymer along the temperature gradient, or if there is an abrupt step-change in the detachment. This work will have valuable insights regarding the optimal temperature for cell detachment from pNIPAM.