AVS 51st International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI1-WeM

Paper BI1-WeM1
Study of Confluent Cell Culture Monolayers by XPS and SIMS

Wednesday, November 17, 2004, 8:20 am, Room 210D

Session: Cell-Surface Interactions
Presenter: D.G. Castner, University of Washington
Authors: M. Greenfeld, University of Washington
H.E. Canavan, University of Washington
X. Cheng, University of Washington
B.D. Ratner, University of Washington
D.G. Castner, University of Washington
Correspondent: Click to Email
Adhered cells transform the surfaces on which they are cultured by excreting and remodeling the underlying extracellular matrix (ECM) proteins. As the ECM is known to play a vital role in the processes of differentiation, motility, and proliferation, the characteristics and identity of the ECM proteins excreted by different cells, or by the same cells throughout its lifetime, are of a great deal of interest in biology and surface science alike. Until now, traditional high vacuum techniques such as X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS) have played only a minor role in the analysis of the ECM, as traditional cell removal techniques are destructive to both the cells and the underlying ECMâ?"in effect damaging the structure of analytical interest. Recently, poly(n-isopropylacrylamide) (pNIPAM) treated tissue culture polystyrene (TCPS) has been developed as a method to non-destructively harvest intact cell monolayers. Using the low-temperature liftoff technique, cell sheets may be non-destructively removed from surfaces and re-deposited atop new surfaces, achieving multilayer structures of different cell types, such are used for tissue engineering. To date, studies of cells harvested via this method have primarily utilized traditional biological techniques to track the morphology of the cells and the location of their ECM proteins. Previously, we have used XPS and SIMS to examine culture surfaces after cell liftoff and identify the ECM proteins retained. In this work, we present the first application of high vacuum techniques to an examination of cell monolayers harvested by low-temperature liftoff. We find that the presence of proteins in the basal surface of the ECM is easily detected via XPS and SIMS. We then compare the identities and relative amounts of ECM proteins at the apical and basal surfaces of the cell sheet to those retained by the underlying surface.