title: Fluorescent silica particles for monitoring oxygen levels in three-dimensional heterogeneous cellular structures.
abstract: Bacterial biofilms are a major obstacle challenging the development of more effective therapies to treat implant infections. Oxygen availability to bacterial cells has been implicated in biofilm formation and planktonic cell detachment; however, there are insufficient tools available to measure oxygen concentrations within complex three-dimensional structures with ∼ 1 µm resolution. Such measurements may complement measures of biofilm structure and cell activity to provide a more comprehensive understanding of biofilm biology. Thus, we developed oxygen-sensing microparticles specifically designed to characterize oxygen transport through the volume of bacterial biofilms. The Stöber method was used to synthesize monodisperse silica microparticles of approximately the same size as a bacterium (∼ 1 µm). Two fluorophores, oxygen-sensitive Ru(Ph(2) phen(3))Cl(2), and the reference fluorophore Nile blue chloride were immobilized on the surface of the particles. We demonstrate application of the microparticles toward measuring the oxygen concentration profiles within a live Staphylococcus aureus biofilm.
authors.affiliation: Department of Chemical, Biochemical & Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, ECS 314, Baltimore, Maryland 21250, USA.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Acosta
authors.forename: Melissa
authors.initials: M
authors.lastname: Velasquez
authors.forename: Katelyn
authors.initials: K
authors.lastname: Williams
authors.forename: Julia M
authors.initials: JM
authors.lastname: Ross
authors.forename: Jennie B
authors.initials: JB
authors.lastname: Leach
mesh_terms: D018441:Biofilms; D002623:Chemistry Techniques, Analytical; D005453:Fluorescence; D010100:Oxygen / Q000032:analysis*; D052638:Particulate Matter; D012822:Silicon Dioxide / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000502:physiology*
chemical_list: D052638:Particulate Matter; D012822:Silicon Dioxide; D010100:Oxygen