Inexpensive and rapid methods for detecting bacterial infections and their corresponding susceptibility to antibiotics are desperately needed. The determination of which antibiotic to use and its administration at dosages that will effectively suppress bacterial growth is important for clinical decision making. Currently, the assessment of antimicrobial susceptibility takes from 24-48 hours. Therefore, we have developed a nanoparticle-based antimicrobial susceptibility assay based on the Concanavalin A-induced clustering of dextran-coated gold nanoparticles. When the bacteria do not grow in the suspension, addition of Concanavalin A results in the formation of extensive dextran gold nanoassemblies. The induction of these large nanoassemblies is mediated by the presence of free carbohydrates, resulting in large shifts in the surface plasmon band of the nanoparticles. In contrast, when the bacteria grow, the levels of free carbohydrates decrease due to enhanced carbohydrate uptake by the proliferating bacteria. This causes a decrease in the size of the gold nanoparticle clusters, causing smaller shifts in the plasmonic band. The gold nanoparticle-based determination of antimicrobial susceptibility provides results within 3 hours and can be used for the high-throughput screening of samples during epidemics and for identification of new antimicrobial agents.
Journal: TechConnect Briefs
Volume: 2, Nanotechnology 2008: Life Sciences, Medicine & Bio Materials – Technical Proceedings of the 2008 NSTI Nanotechnology Conference and Trade Show, Volume 2
Published: June 1, 2008
Pages: 593 - 594
Industry sectors: Medical & Biotech | Sensors, MEMS, Electronics
Topics: Chemical, Physical & Bio-Sensors