Evan Hardy Collegiate- Saskatoon, SK

Silver nanoparticles are known to inhibit bacterial growth, and students from Evan Hardy Collegiate in Saskatoon, SK were interested in learning if chemical changes take place in the nanoparticles following exposure to bacteria. They used the Hard X-ray Microanalysis (HXMA) beamline to study their selected samples, chosen based on which cultures showed the greatest amount of bacterial inhibition or “kill zones” from the silver nanoparticles. The use of nano-silver over the past years has increased. It can be found in household products as well as in the medical community because of its unique properties. An interested group of high school students and their teacher worked with scientists through the Students on the Beamline program at the Canadian Light Source to learn about nano-particles, specifically nano-silver, and its effect on the clinically relevant Class II gram negative bacteria, Pseudomonas aeruginosa. This was done by comparing the treatments of AgNO3(50mM), ZnO, Polysporin, three different sized particles of nano-silver, and a commercial nano-silver impregnated wound dressing each of which was placed on the bacterial cultures. Zones of inhibition (ZOI) were measured and recorded. Samples were prepared from the ZOI affected by the treatments and measured using synchrotron Ag K-edge X-ray Absorption Near-Edge Structure (XANES) spectroscopy as well as Zn K-edge XANES. The three different sizes of Ag metal nano-particles resulted in no speciation changes as the XANES analysis revealed only Ag metal which was consistent with the small zones of inhibition. The P. aeruginosa culture treated with the nano-silver wound dressing was found to contain both Ag cysteine and silver. ZnO was an effective treatment as well as indicated by the large ZOI. ZnO was shown by XANES analysis to contain many different components after reacting with the bacteria. The largest ZOI was AgNO3 (50mM). The best fit for the XANES analysis for AgNO3 (50mM) samples were inconclusive even though it was compared against seven standards. There were speciation changes to silver when the AgNO3 (50mM) and ZnO interacted with the bacteria.

	Late hours developing a proposal to submit to Students on the Beamlines.
Gloria introduces silver nanoparticles to bacterial culture.
	The bacterial culture displaying the ‘killzone’.
As the students approach their beamline to begin their synchrotron research, a film crew is on site to capture it all for a documentary!
	Ryan places the sample in the holder.
Miranda opens the shutter to allow the x-rays to enter the experimental hutch.
	Dan prepares the sample.
The sample in its holder in the HXMA beamline
	Gloria runs the beamline computers and begins data analysis.
What the data looks like on the computer monitor
	Miranda and Dan present their poster to other synchrotron users at the annual meeting – winning a prize in the process!

Last modified: 2009-07-07 10:07:55