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Research:



Interfacial processes and molecular self-assembly applied to nanoparticle activity, biomaterials, and biosensors.

Our research applies molecular self-assembly and advanced analytical techniques to detect and direct interfacial phenomenon, with specific projects in:

  1. Understanding the fate and transport of engineered nanoparticles in agricultural settings to predict the short- and long-term implications of nanotechnology in agriculture. Our interdisciplinary research group studies metal oxide nanoparticle interactions with beneficial soil microbes and high value crops such as wheat.

  1. Molecular Imprinting: Using monolayer assembly techniques, molecularly imprinted thin films are constructed as artificial recognition elements against proteins, with the aim of developing sensors capable of recognizing a single protein from a mixture as well as recognizing changes in a given protein conformation.

  1. Materials Biocompatibility: The nano-scale chemical and physical properties of biomaterials dictate subsequent events such as non-specific protein and cell adsorption that in turn result in fouling and rejection of the material. Using hemodialysis membranes and middle ear ventilation tubes as model biomaterials, we are characterizing the surface properties and investigating the resulting interactions of proteins, bacteria, and lipopolysaccharides.

  1. Biofilms: Bacterial colonization of a surface and subsequent biofilm formation can be hindered through coating the surface with biocidal or surface passivating agents. We are tuning the activity of surfactants and nanoparticles (and mixtures thereof) to target bacteria, interfere with quorum sensing (bacterial communication), and thus control growth and subsequent biofilm forming abilities. The interplay of passive and active inhibitory mechanisms is investigated.

  1. Nanoparticles and Bacteria: Bacterial colonization of a surface and subsequent biofilm formation is important in medicine and environmental settings. Biofilm formation on implant materials as well as host tissues is a primary cause for device failure and persistent infection. In contrast, environmental biofilms play key roles in nutrient cycling, waste remediation, and crop health. With the increasing use of nanoparticles their intentional and inadvertent release into the environment is of concern. We are investigating the activity of metal oxide nanoparticles on bacterial metabolism and biofilm forming ability using a bioluminescent bacterial construct as a sentinel organism for rapid determination of bacterial response (increased or decreased light output) to a variety of NP challenges, including ZnO, CuO, and Ag. Synergistic activity of NP mixtures as well as influence of NP size and shape are being investigated.

Other Experience:

  • 2009-2010 Visiting faculty, University of Auckland Chemistry and Materials Dept.
  • 1998-1999 NSF-NATO Postdoctoral Fellow
  • 1989-1990 Undergraduate Exchange Program: University of Humacao, PR
Honors:

  • 2005-2008 USDA-NRI Young Investigator Award