Scholarly Work - Center for Biofilm Engineering
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/9335
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Item High-density targeting of a viral multifunctional nanoplatform to a pathogenic, biofilm-forming bacterium(2007-04) Suci, Peter A.; Berglund, Deborah L.; Liepold, Lars Otto; Brumfield, Susan; Pitts, Betsey; Davison, William M.; Oltrogge, Luke; Hoyt, Kathryn Olivia; Codd, Sarah L.; Stewart, Philip S.; Young, Mark J.; Douglas, TrevorNanomedicine directed at diagnosis and treatment of infections can benefit from innovations that have substantially increased the variety of available multifunctional nanoplatforms. Here, we targeted a spherical, icosahedral viral nanoplatform to a pathogenic, biofilm-forming bacterium, Staphylococcus aureus. Density of binding mediated through specific protein-ligand interactions exceeded the density expected for a planar, hexagonally close-packed array. A multifunctionalized viral protein cage was used to load imaging agents (fluorophore and MRI contrast agent) onto cells. The fluorescence-imaging capability allowed for direct observation of penetration of the nanoplatform into an S. aureus biofilm. These results demonstrate that multifunctional nanoplatforms based on protein cage architectures have significant potential as tools for both diagnosis and targeted treatment of recalcitrant bacterial infections.Item Intracellular distribution of macrophage targeting ferritin–iron oxide nanocomposite(2009-01) Uchida, M.; Willits, Deborah Ann; Muller, Karin; Willis, Ann F.; Jackiw, Larissa; Jutila, Mark A.; Young, Mark J.; Porter, Alexandra E.; Douglas, TrevorIntracellular distribution of iron oxide nanoparticlesincorporated within a ferritin mutant that displays genetically introduced cell-targeted peptides (RGD-4C) on its exterior surface are investigated using scanning transmission electron microscopy with a high-angle annular dark-field detector. The particles (indicated by arrows) internalized into macrophages much more effectively than those with noncell-targeted ferritin.Item A Human ferritin iron oxide nano-composite magnetic resonance contrast agent(2008-11) Uchida, M.; Terashima, Masahiro; Cunningham, Charles H.; Suzuki, Yoriyasu; Willits, Deborah Ann; Willis, Ann F.; Yang, Philip C.; Tsao, Philip S.; McConnell, Michael V.; Young, Mark J.; Douglas, TrevorMacrophages play important roles in the immunological defense system, but at the same time they are involved in inflammatory diseases such as atherosclerosis. Therefore, imaging macrophages is critical to assessing the status of these diseases. Toward this goal, a recombinant human H chain ferritin (rHFn)-iron oxide nano composite has been investigated as an MRI contrast agent for labeling macrophages. Iron oxide nanoparticles in the form of magnetite (or maghemite) with narrow size distribution were synthesized in the interior cavity of rHFn. The composite material exhibited the R2 relaxivity comparable to known iron oxide MRI contrast agents. Furthermore, the mineralized protein cages are readily taken up by macrophages in vitro and provide significant T2* signal loss of the labeled cells. These results encourage further investigation into the development of the rHFn-iron oxide contrast agent to assess inflammatory disease status such as macrophage-rich atherosclerotic plaques in vivo.Item Targeted delivery of a photosensitizer to Aggregatibacter actinomycetemcomitans biofilm(2010-04) Suci, Peter A.; Kang, Sebyung; Gmür, Rudolf; Douglas, Trevor; Young, Mark J.The ability to selectively target specific biofilm species with antimicrobials would enable control over biofilm consortium composition, with medical applications in treatment of infections on mucosal surfaces that are colonized by a mixture of beneficial and pathogenic microorganisms. We functionalized a genetically engineered multimeric protein with both a targeting moiety (biotin) and either a fluorophore or a photosensitizer (SnCe6). Biofilm microcolonies of Aggregatibacter actinomycetemcomitans, a periodontal pathogen, were targeted with the multifunctional dodecamer. Streptavidin was used to couple biotinylated dodecamer to a biotinylated anti-A. actinomycetemcomitans antibody. This modular targeting approach enabled us to increase the loading of photosensitizer onto the cells by a cycle of amplification. Scanning laser confocal microscopy was used to characterize transport of fluorescently tagged dodecamer into the microcolonies and targeting of the cells with biotin-labeled, fluorescently tagged dodecamer. Light-induced activity of the targeted photosensitizer reduced the viability of A. actinomycetemcomitans biofilm, as indicated by membrane permeability to propidium iodide. The functionalized multimeric protein promises to be a useful tool for controlling periodontal biofilm consortia and offers a modular design whereby moieties that target different species can be readily combined with the functionalized protein construct.Item Photo-induced H2 production by [NiFe]-hydrogenase from T. roseopersicina covalently linked to a Ru(II) photosensitizer(2012-01) Zadvornyy, Oleg A.; Lucon, Janice E.; Gerlach, Robin; Zorin, Nikolay A.; Douglas, Trevor; Elgren, T. E.; Peters, John W.The potential of hydrogen as a clean renewable fuel source and the finite reserves of platinum metal to be utilized in hydrogen production catalysts have provided the motivation for the development of non-noble metal-based solutions for catalytic hydrogen production. There are a number of microorganisms that possess highly efficient hydrogen production catalysts, termed hydrogenases, that generate hydrogen under certain metabolic conditions. Although hydrogenases occur in photosynthetic microorganisms, the oxygen sensitivity of these enzymes represents a significant barrier in directly coupling hydrogen production to oxygenic photosynthesis. To overcome this barrier, there has been considerable interest in identifying or engineering oxygen tolerant hydrogenases or generating mimetic systems that do not rely on oxygen producing photocatalysts. In this work, we demonstrate photo-induced hydrogen production from a stable [NiFe]-hydrogenase coupled to a [Ru(2,2'-bipyridine)2(5-amino1,10 phenanthroline)]2+ photocatalyst. When the Ru(II) complex is covalently attached to the hydrogenase, photocatalytic hydrogen production occurs more efficiently in the presence of a redox mediator than if the Ru(II) complex is simply present in solution. Furthermore, sustained hydrogen production occurs even in the presence of oxygen by presumably creating a local anoxic environment through the reduction of oxygen similar to what is proposed for oxygen tolerant hydrogenases. These results provide a strong proof of concept for engineering photocatalytic hydrogen production in the presence of oxygen using biohybrid mimetic systems.