AVS 46th International Symposium
    Biomaterial Interfaces Group Wednesday Sessions
       Session BI-WeP

Paper BI-WeP19
TOF-SIMS Analysis of the Candida Albicans Cell Surface

Wednesday, October 27, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: H. Shi, Montana State University
Authors: H. Shi, Montana State University
B.J. Tyler, Montana State University
Correspondent: Click to Email
The most common cause of failure for medical devices is infection, and the pathogenic yeast Candida albicans is the third leading cause of these infections. Adhesion is the first step in establishing an infection, the initial adhesion of microorganisms to synthetic polymer surfaces involves physicochemical interactions between molecules present at the polymer surface and those present on the cell surface. These interactions are not well defined, and insight into this area could lead to better material construction to effectively control the infection. The objective of this thesis is to study the initial adhesion event of C. albicans grown in glucose-based medium and galactose-based medium to Fluorinated Ethylene Propylene(FEP) and use Secondary Ion Mass Spectrometry(SIMS) to study the surface structural differences between these two cell surfaces with an attempt to correlate surface functionalities to the adhesion results. A freeze-drier with ultimate vacuum less than 1.00x10-9torr was constructed "in house" to freeze-dry cells for SIMS analysis. A filtration method was used to prepare a smooth layer of cells to be freeze-dried. Scanning Electron Microscopy showed that the freeze-dried cells appeared intact. High resolution SIMS spectra were obtained from these freeze-dried cell surfaces and Linear Discriminant Function Analysis combined with Principle Components Analysis were used to analyze the SIMS spectra. The results showed that the surfaces of glucose-grown cells contained more hydrophobic amino acid residues relative to those of galactose-grown cells. These hydrophobic amino acid residues probably promoted the adherence of glucose-grown cells to FEP surface. The results obtained in this study suggest that hydrophobic interactions are important in the initial attachment of C. albicans to FEP surface. The SIMS spectra presented in this study were the first report of the freeze-dried C. albicans.