PSIS Graduate Student Wins 1st Place Award for Poster Presentation

Congratulations to Wei Jiang, a Plant, Soil & Insect Sciences Graduate Student of Dr. Baoshan Xing, for winning first place for her student poster presentation at the "Water Dependencies in New England" 6th Annual Conference. The event was held on April 7, 2009 at the University of Massachusetts in Amherst. The conference included a wide array of talks, poster presentations, and exhibits concerning many areas of water resources in New England. For more information about the conference, please go to the conference website.

The picture above shows Wei Jiang (left) with her 1st place award, Yuan Xin (center), a UMass Amherst Civil & Environmental Engineering Graduate Student, with his 2nd place award, and the Poster Award Sponsor, Robert Thompson (left), Director of the Westfield River Environmental Center at Westfield State College.

The title of Wei Jiang's poster was "Toxicity of Oxide Nanoparticles to Bacteria in Water." Coauthors on the poster were Dr. Boashan Xing and his Research Assistant Hamid Mashayekhi. The poster abstract is as follows:

Nanotechnology is one of the fast growing sections of high tech economy with more than 800 products using nanoparticles (NPs) reported in August 2008. Oxide NPs are a large group of nanomaterials widely applied in different industrial, medical, personal and military fields. Their release into aquatic environments would be inevitable because of their widespread production and use. In this study, the toxicity of nano-scaled aluminum oxide, silicon dioxide, titanium dioxide, and zinc oxide to gram-positive Bacillus subtilis, gram-negtive Escherichia coli and Pseudomonas fluorescence was examined and compared to that of bulk (micro-scaled) materials of the same composition. All nano-scaled particles but titanium showed higher toxicity (at 20 mg/L) than their bulk counterparts. ZnO was the most toxic among the three NPs, causing 100% mortality to the three tested bacteria. Al 2O 3 NPs had a mortality rate of 57% to B. subtilis, 36% to E. coli, and 70% to P. fuorescens. SiO 2 NPs killed 40% of B. subtilis, 58% of E. coli, and 70% of P. fluorescens. The role of dissolved metal ions in NPs toxicity was also examined. Bacterial responses to NPs were different from their bulk counterparts, which indicated that the toxicities of NPs are size-related. Hence nanoparticle toxicity mechanisms need to be studied thoroughly. TEM images showed attachment of NPs to the bacteria, which can be ascribed to electrostatic force and surface bonding, suggesting that toxicity of NPs was affected by their attachment to the bacteria. Mechanistic understanding is required for the NPs behavior on the bacterial surface.

Congratulations to Wei Jiang on her award, and to Hamid Mashayekhi and Dr. Baoshan Xing as well, for their excellent research efforts.