In vitro monocyte adhesion and activation on modified FEP copolymer surfaces

Abstract

SYNOPSISThe functional group content and the ionic state of functional groups present on a series of surface modified poly(tetrafluoroethylene/hexafluoropropylene) (FEP) copolymers were characterized by electron spectroscopy for chemical analysis (ESCA), contact angle, and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Additionally, after a protein was preadsorbed on these surfaces, in uitro cell (monocyte) adhesion and activation were analyzed. The two proteins in this study were fibrinogen and immunoglobulin-(; (IgG). Four modified FEP surfaces were prepared with increasing concentration of carboxyl groups relative to amide groups; ESCA was used to quantify the functional group content. To characterize the ionic state of the functional groups at physiological pH (7.1), the ATR-FTIR spectra were collected at various pH levels. Collectively, the contact angle, ESCA, and ATR-FTIR results suggested that the amide groups were unprotonated and the carboxyl groups were ionized a t the physiological pH. The results from the in uitro studies showed that on the fibrinogen preadsorbed surfaces, monocyte adhesion was higher and monocyte activation was lower on the three surfaces that contained carboxyl groups compared to the FEP surface that had only amide groups. Conversely, the results indicated that the surface chemistry had no significant effect on monocyte adhesion or activation on the IgG preadsorbed surfaces. 0

Cellular Attachment to Ultraviolet Ozone Modified Polystyrene Surfaces

“…In the present study, we examined the attachment of Chinese hamster ovary (CHO) cells. The kinetics of cell attachment was followed using a Sysmex CDA 500 particle counter, a very simplistic but accurate cell counting method which has been sparingly used. ,, Other methods, which include radioactive labeling, , counting by using a haemocytometer, image analysis, and manual counting 4,14 techniques are more labor intensive, which results in less data being available and larger statistical variation. Data for previous attachment assays has shown large scatter …”

“…It has been observed that the specific surface chemistry and polar free energy of polymer substrates can influence the adhesion and subsequent cell growth process, either directly or indirectly through the serum protein layer which rapidly adsorbs onto the surface prior to cell adhesion. Consequently, surface modification treatments such as plasma 3,4,6,[10][11][12] or corona oxidation, 13,14 together with the adsorption of proteins and surfactants, 1,2,5,[15][16][17] have been investigated and shown to positively influence the characteristics of the cell growth process. However, detailed or quantitative studies that establish the relationship between the precise physicochemical properties of the culture system and the response of cells in culture have, until now, been lacking from the literature.…”