AVS 52nd International Symposium
    Biomaterial Interfaces Monday Sessions
       Session BI-MoP

Paper BI-MoP14
The Effect of Covalent Tethering on the Function of a Quaternary Ammonium Antimicrobial Compound

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Biomaterial Interfaces Poster Session
Presenter: D.M. Stamper, NSWC, Carderock Division
Authors: R.A. Brizzolara, NSWC, Carderock Division
D.M. Stamper, NSWC, Carderock Division
R.M. Lennen, NSWC, Carderock Division
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In the development of antimicrobial coatings and materials, biocidal molecules can be incorporated into a coating either as free molecules, or by covalently tethering the molecules to the coating or surface. Covalently tethering a biocidal moiety to a coating or surface has the benefit of reducing leaching of the biocide into the environment. However, the effects of covalent tethering on the biocidal activity of the molecule need to be more fully characterized. This paper reports on experiments to determine the effects of surface-immobilization on the activity of an antimicrobial molecule. Monolayers of a covalently bound organosilane containing a quaternary ammonium functional group (QAS) were used as the test platform. QAS monolayers were bound to silica surfaces and characterized by x-ray photoelectron spectroscopy (XPS). Viability of Staphylococcus aureus exposed to QAS-derivatized surfaces was measured by dilution plate counting. Control substrates derivitized with an amino-terminated silane were also included in the analysis. Flat surfaces derivatized with QAS did not possess antimicrobial activity. Results will be presented that differentiate between 1. loss of biocidal activity as a result of covalent tethering of QAS molecules versus 2. insufficient dose of antimicrobial molecules per S. aureus cell, as the cause of lack of antimicrobial activity of QAS-derivatized surfaces. It is expected this work will contribute to the development of materials and coatings with inherent antimicrobial properties and to reduced use of decontaminating solutions containing toxic chemicals. This work was funded by the NSWC, Carderock Division In-House Laboratory Independent Research (ILIR) program.