3 research outputs found
Imaging Pseudomonas aeruginosa Biofilm Extracellular Polymer Scaffolds with Amphiphilic Carbon Dots
Imaging <i>Pseudomonas aeruginosa</i> Biofilm Extracellular Polymer Scaffolds with Amphiphilic Carbon Dots
Biofilm
formation is a critical facet of pathogenesis and resilience
of human, animal, and plant bacteria. Extracellular polymeric substances
(EPS) constitute the physical scaffolding for bacterial biofilms and
thus play central roles in their development and virulence. We show
that newly synthesized amphiphilic fluorescent carbon dots (C-dots)
readily bind to the EPS scaffold of <i>Pseudomonas aeruginosa</i>, a major biofilm-forming pathogen, resulting in unprecedented microscopic
visualization of the EPS structural features. Fluorescence microscopy
analysis utilizing the C-dots reveals that the <i>P. aeruginosa</i> EPS matrix exhibits a remarkable dendritic morphology. The experiments
further illuminate the growth kinetics of the EPS and the effect of
external factors such as temperature. We also show that the amphiphilic
C-dot platform enabled screening of substances disrupting biofilm
development, specifically quorum sensing inhibitors
Poly(methyl methacrylate)-Supported Polydiacetylene Films: Unique Chromatic Transitions and Molecular Sensing
Polydiacetylenes (PDAs) constitute a family of conjugated polymers exhibiting unique colorimetric and fluorescence transitions, and have attracted significant interest as chemo- and biosensing materials. We spin-coated PDA films upon poly(methyl methacrylate) (PMMA), and investigated the photophysical properties and sensing applications of the new PDA configuration. Specifically, the as-polymerized blue PDA layer underwent distinct transformations to purple, red, and yellow phases, which could be quantified through conventional color scanning combined with application of image analysis algorithms. Furthermore, we recorded a reversible red-purple PDA transition that was induced by ultraviolet irradiation, a phenomenon that had not been reported previously in PDA film systems. We show that distinct color and fluorescence transitions were induced in the PMMA-supported PDA films by amphiphilic substances-surfactants and ionic liquids-and that the chromatic transformations were correlated to the analyte structures and properties. Overall, this study presents a new chromatic PDA film system in which noncovalent interactions between the PMMA substrate and spin-coated PDA give rise to distinct chromatic properties and molecular sensing capabilities. © 2014 American Chemical Society