Colorimetric Nanoparticles for Biosensing

Title of Thesis: COLORIMETRIC NANOPARTICLES FOR BIOSENSING Kankindi Rwego, Master of Science, 2014 Thesis directed by: Professor Peter Kofinas Department of Bioengineering In order to develop biosensors that change color upon the detection of a pathogen, nearly monodisperse polymer nanoparticles that can arrange into an ordered lattice structure that emits structural color, which is color free of pigment, or dye are synthesized. This work investigates methods for preparing electrostatically stabilized lattice structures by investigating the co-polymerization of polystyrene latex particles with the ionic co-monomer sodium-2-acrylamido-2-methylpropane sulfonate ("AMPS") through varying emulsion polymerization reaction parameters. Additionally, this work is the first to deposit polystyrene-co-poly(N, N-dimethylacrylamide) core-shell nanoparticles onto a glass substrate, entrap in an elastomer matrix, and successfully show color change from green to red in less than 30 seconds upon exposure to a non-polar solvent. As such, the ability to induce a color change that is observable by the unaided human eye has been established. Therefore, this thesis promises to lead to the development of colorimetric biosensors in the near future