Effects of intact and degraded quantum dots on bacterial growth

ENVR 78

Shaily Mahendra, mahendras@rice.edu1, Huiguang Zhu, hzhu@rice.edu2, Vicki L Colvin, colvin@rice.edu3, and Pedro J. Alvarez, alvarez@rice.edu1. (1) Department of Civil and Environmental Engineering, Rice University, MS-317, 6100 Main St., Houston, TX 77005, (2) Department of Chemistry, Rice University, MS-60, 6100 Main St., Houston, TX 77005, (3) Dept. of Chemistry, Dept. of Chemical and Biomolecular Engineering and Center for Biological and Environmental Nanotechnology, Rice University, 6100 Main St., MS-60, Houston, TX 77005
Quantum dots (QDs) are nanomaterials used for electronics, solar energy generation and medical imaging applications. QDs typically consist of a reactive metalloid core surrounded by an inorganic shell and are coated with amphiphilic organics to make them water soluble and conjugate with bioactive moieties. During their production, use, and disposal, QDs may be released to the environment where their surface coatings may dissolve, with subsequent leaching of the core/shell metals that may be toxic to microbial populations that are important to ecosystem health. In this study, two bacterial strains, Bacillus subtilis and Escherichia coli, were incubated with four types of QDs. QD exposure to various pH conditions resulted in rapid release of cadmium, selenium and zinc and decreased the rate and extent of bacterial growth. In contrast to capped QDs, uncapped QDs were bactericidal, implying that weathering of the QD cap in the environment will increase metal release and ecotoxicity.
 

Environmental Behavior and Fate of Manufactured Nanomaterials
1:30 PM-5:30 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 235, Oral

Division of Environmental Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008