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This article in JEQ

  1. Vol. 39 No. 6, p. 1934-1941
    Received: Nov 16, 2009

    * Corresponding author(s): jmorrow@nist.gov
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Association of Quantum Dot Nanoparticles with Pseudomonas aeruginosa Biofilm

  1. Jayne B. Morrow *a,
  2. Catalina Arango P.b and
  3. R. David Holbrook
  1. a Biochemical Science Division, National Institute of Standards and Technology, 100 Bureau Dr., MS 8312, Gaithersburg, MD 20878
    b Dep. of Molecular and Cell Biology, Univ. of Connecticut, 91 N. Eagleville, U-3125, Storrs, CT 06269
    c Surface and Microanalysis Division, National Institute of Standards and Technology, 100 Bureau Dr., MS 8371, Gaithersburg, MD 20878. Certain commercial equipment, instruments, or materials are identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose. Assigned to Associate Editor Gregory Lowry


Quantum dots (QDs) of two different surface chemistries (carboxyl [COOH] and polyethylene glycol [PEG] modified) were utilized to determine the impact of surface functionality on QD mobility and distribution in Pseudomonas aeruginosa PAO1 biofilms. Confocal laser scanning microscopy was utilized to evaluate QD association with biofilm components (proteins, cells, and polysaccharides). Quantum dots did not preferentially associate with cell surfaces compared but did colocalize with extracellular proteins in the biofilm matrix. Neither PEG nor COOH QDs were found to be internalized by individual bacterial cells. Neither QD functionality nor flow rate of QD application (0.3 mL min−1 or 3.0 mL min−1) resulted in a marked difference in QD association with P. aeruginosa biofilms. However, center of density determinations indicated COOH QDs could more easily penetrate the biofilm matrix by diffusion than PEG QDs. Biofilms with PEG QDs associated had rougher polysaccharide layers and rougher cell distribution than biofilms with COOH QDs. This work suggests natural biofilms may serve as deposition locations in natural and engineered environmental systems, and biofilm structural parameters may change based on exposure to nanomaterials of varied physical characteristics.

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