Carbohydrate chemosensors based on stimuli-responsive complex emulsions
Analytical Chemistry
Organic Molecular Chemistry - Synthesis and Characterisation
Final Report Abstract
Multiphase complex emulsions formed from two or more immiscible solvents offer a unique platform as new materials for chemical sensor applications. The temperature controlled miscibility of fluorocarbons (F) and hydrocarbons (H) enables a temperature induced phaseseparation, leading to structured emulsion droplets of H and F in water (W). The morphology of these complex emulsions can be alternated between encapsulated (F in H, and H in F), and Janus configurations by varying the interfacial tensions using surfactants. By employing stimuli-responsive surfactants a morphology change can be triggered in response to external stimuli such as the presence of specific analytes. This, in combination with their unique optical properties, enables the application of dynamic liquid colloids as new transduction material for chemo- and bio-sensing applications. During this DFG-funded research stay, new sensing paradigms that take advantage of the unique chemical-structural-optical coupling in chemically functionalized fluorescent double emulsion droplets were developed. Specifically, the potential of these micro-colloids to manipulate light in form of waveguides led to the realization of a series of optical transduction methods, where an adjustment of the refractive indices of the solvents resulted in a new unprecedented control of light propagation inside the emulsion droplets. The control over the total internal reflection of light from outside and inside the emulsion droplets paved the way towards new optical sensory transduction schemes based on fluorescence, refractive index changes and variations in light transmission. The strong correlation between experimentally obtained data and theoretical raytracing models provided for an understanding of the underlying optical phenomena. Dynamic interface triggered morphology changes were used to create rapid and highly selective and sensitive methods for the detection of radioactive gamma irradiation, caffeine, the carbohydrates fructose, glucose, mannose and mannan, Zika virus as well as for sensing of foodborne pathogens such as Salmonella, E.coli and Listeria. All sensing schemes rely on the following transduction scheme: A chemical recognition of the analyte at the interface transduces into a droplet reconfiguration or morphology change. An optical read-out of the droplets’ response was then acoomplished by measuring (i) the directional light emission of dyed complex emulsions, (ii) the transmission of light passing through droplet monolayers, (iii) refractive index changes on a glass waveguide, or (iv) the variations in emission intensities of dyes dissolved inside these liquid colloids, which are modulated by the ‘inner filter effect’. As a result of this research stay, the initially aimed sensing scheme was implemented and various additional unprecedented findings led to new and improved discoveries and ultimately to the development of a whole new series of chemo- and bio-sensors. Most notably, the herein developed new and efficient sensing platforms facilitate the early detection of foodborne pathogens and thereby can help to reduce food poisoning around the globe.
Publications
- (2019) Rapid Detection of Salmonella enterica via Directional Emission from Carbohydrate-Functionalized Dynamic Double Emulsions. ACS central science 5 (5) 789–795
Zeininger, Lukas; Nagelberg, Sara; Harvey, Kent S.; Savagatrup, Suchol; Herbert, Myles B.; Yoshinaga, Kosuke; Capobianco, Joseph A.; Kolle, Mathias; Swager, Timothy M.
(See online at https://doi.org/10.1021/acscentsci.9b00059) - (2019): Emulsion Agglutination Assay for the Detection of Protein-Protein Interactions: An Optical Sensor for Zika Virus. In: ACS Sensors 4 (1), S. 180–184
Q. Zhang, L. Zeininger, K. Sung, E. Miller, H. Sikes, T. M. Swager
(See online at https://doi.org/10.1021/acssensors.8b01202) - (2019): Waveguide-based chemo- and biosensors: complex emulsions for the detection of caffeine and proteins. In: Lab on a chip 19 (8), S. 1327–1331
L. Zeininger, E. Weyandt, S. Savagatrup, K. Harvey, T. M. Swager
(See online at https://doi.org/10.1039/c9lc00070d) - “Morphology-dependent Luminescence in Liquid Colloids”, submitted
C. Lin, L. Zeininger, T. M. Swager
(See online at https://doi.org/10.1021/jacs.8b13215)
