Liquid crystal emulsions stabilized by nanoparticles

Abstract

Devices and methods for using changes in the orientation of micrometer sized dispersed liquid crystal domains to detect or quantify analytes in a test sample, including amphiphilic analytes, are disclosed. The dispersed liquid crystal domains are defined by an interface, and one or more nanoparticles or nanoparticle-containing complexes are adsorbed to the interface. As a result of the adsorption of the nanoparticles or nanoparticle-containing complexes at the interface, the microdomains are stabilized, and resist coalescing for extended periods of time, unlike previously known devices using liquid crystal emulsions for analyte detection. When the dispersed liquid crystal microdomains are exposed to the test sample, any changes in the orientation of the liquid crystal microdomains (such as from the bipolar to radial) are detected. Such changes in orientation signal the presence of analyte in the test sample, and the proportion of liquid crystal microdomains exhibiting the change in orientation is correlated with the quantity of analyte in the test sample. The nanoparticle used, the amphiphile used in the nanoparticle-containing complex, or both may be selected to optimize the sensitivity and/or selectivity of the device for a given analyte.