A new antimicrobial surface developed by researchers at
the University of New Mexico is potentially inhospitable to
methicillin-resistant Staphylococcus aureus but safe for humans
and animals.
The new material, conjugated polyelectrolyte (CPE), has
an arylene-ethynylene repeat-unit structure and has been shown to be effective
at killing gram-negative bacteria, enabling its use in a wide range of
potential applications.
The researchers pointed out that certain light-activated
CPEs are inert toward bacteria in the absence of light and display
bacteria-killing activity with the addition of light. They noted that this
opens up significant potential – including the possibility of using the
polymers as antibacterial countertops that may be sterilized using regular
fluorescent lights.
Until recently, it was unknown if the CPEs would exhibit
similar biocidal activity toward mammalian cells. The in-vitro testing
performed on these CPEs at the University of New Mexico is reported as “an
important first step in determining whether [the CPEs] are harmful to humans at
concentrations envisioned in potential applications.”
The researchers exposed bovine aortic endothelial cells
to two different CPEs for increasing periods of time — from 10 minutes to
24 hours — in both light and dark conditions. The relative cytotoxicity
was then assessed using a live/dead fluorescence assay, and imaged via
epi-fluorescence microscopy.
The group found that while CPEs targeted various harmful
strains such as P. aeruginosa PAO1 and C. marina, the polymers do
not appear to be toxic toward mammalian cells when the cells are exposed to the
polymers in both light and dark conditions.
The researchers reported that they are currently
evaluating cytotoxicity at concentrations above the micromolar concentrations
tested to date, in the effort to correlate mammalian test conditions to
bacterial test conditions and include an epithelial cell line.
For more information:
- Wilde KN. Paper BI-ThP-14. Presented at the American Vacuum Society 57th
International Symposium & Exhibition. Oct. 17-22, 2010. Albuquerque, New
Mexico.