(188y) A Study of the Effect of Solvent-Based Sterilization On the Reversible Adhesion of Biological Cells to a Thermoresponsive Surface

Poly(N-isopropyl acrylamide) (pNIPAM) is a thermoresponsive polymer that is widely used in bioengineering applications, including tissue culture engineering, single cell adhesion/detachment, and biofouling prevention. Although there are many ways to treat surfaces with pNIPAM, plasma polymerization is one of the more adaptable ways for coating surfaces for the use in tissue culture experiments. While plasma polymerization creates a sterile environment useful for tissue culture, occasionally, additional sterilization techniques must be used. Some sterilization methods include using UV light to sterilize the surfaces, and the use of different solvents, such as ethanol. To date, there have been no studies on the effect of these sterilization techniques on the reversible adhesion of biological cells on pNIPAM treated surfaces. In this work, we investigate the effect of different sterilization techniques (e.g., ethanol and UV light) on the thermoresponsive nature of pNIPAM. Substrates were coated using plasma polymerization (ppNIPAM), after which they were sterilized using solvents, and characterized to determine if the solvents changed the thermoresponsive nature of the polymer. X-ray photoelectron spectroscopy (XPS) and interferometry were used to determine the surface chemistry and thickness of our ppNIPAM surfaces. Goniometry was used to confirm the thermoresponsive nature of our surfaces. Finally, we tested the adhesion and detachment of cells on the surfaces using bovine aortic endothelial cells (BAECs). We found that the use solvents as sterilizing agents does have an effect on the thermoresponsive nature of pNIPAM (as demonstrated by the decreased detachment of cells from the surfaces), even when the pNIPAM film's chemistry appears unaffected.