| AVS 54th International Symposium | |
| Biomaterial Interfaces | Thursday Sessions |
| Session BI-ThP |
| Session: | Biomaterial Interfaces Poster Session |
| Presenter: | T Corbitt, University of New Mexico |
| Authors: | T Corbitt, University of New Mexico L.K. Ista, University of New Mexico K. Ogawa, University of New Mexico S. Chemburu, University of New Mexico G.P. Lopez, University of New Mexico K. Schanze, University of Florida D. Whitten, University of New Mexico |
| Correspondent: | Click to Email |
Conjugated polyelectrolytes (CPs) are polymers that contain ionic solubilizing groups. These materials are water soluble and feature strong visible absorption and fluorescence. Recently we have shown that CPs functionalized with cationic groups such as trimethyl ammonium (1) and diazobicyclooctane bis quaternary salt (2) polyphenyleneethynylene display efficient light-activated biocidal activity against a variety of microorganisms including Escherichia coli, Cobetia marina, Pseudomonas aeruginosa and Bacillus anthracis, Sterne spores. When bacteria are mixed with aqueous solutions of the polymers the CPs form a surface coating on the microorganism. Irradiation of the bacteria surface-coated with polymers 1 or 2 leads to efficient deactivation of the bacteria as revealed by culturing and live/dead assays. We have also demonstrated that CPs are effective against bacteria when coated at near monolayer coverage on a surface. An additional format currently under investigation involves polymers with the repeat unit of 1 grown covalently from the surface of silica nanoparticles and microspheres (SGCP). The polymer coatings of the SGCPs are more rough and appear from studies using confocal fluorescence microscopy and electron microscopy to protrude from the surface. We find that the SGCP entrap Cobetia marina; live-dead assays of entrapped bacteria kept in the dark and irradiated with visible light reveal that bacteria entrapped on the surface of a 5 micron SGCP are killed while those kept for a similar period in the dark remain viable. We are currently determining whether the light-activated pathogen killing requires molecular oxygen and, if so, whether singlet oxygen is a key intermediate. Our observation that bacteria are not only killed but also degraded suggests that singlet oxygen may subsequently generate much more powerful reactive oxygen species. Structure-property relationships are being developed to optimize the biocidal effect of specific CPs, with the ultimate objective being to develop a new class of polymer-based materials and coatings that are highly effective antimicrobial agents with broad-spectrum activity. The CPs offer advantages over low molecular weight compounds in that they are relatively stable and easily adapted to form robust coatings. Their ease in processing indicates they can be incorporated into filtration devices, foams, paints and fibers for diverse protection applications.