Optical detection of lithocholic acid with liquid crystal emulsions.

Tanmay Bera, Jiyu Fang

Department of Materials Science and Engineering, University of Central Florida, Orlando, Florida 32826, United States.

Langmuir : the ACS journal of surfaces and colloids 2013 Jan 8

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The concentration level of bile acids is a clinical biomarker for the diagnosis of intestinal diseases because individuals suffering from intestinal diseases have a sharply increased concentration of bile acids at micromolar levels. Here, we report the detection of lithocholic acid (LCA) in aqueous solution by using surfactant-stabilized 4-n-pentyl-4'-cyanobiphenyl (5CB) liquid crystal droplets as an optical probe. We find that the surfactant adsorbed at the 5CB/water interface can be replaced by LCA, triggering a radial-to-bipolar configuration transition of the 5CB in the droplets. By simply observing the LCA-triggered transition with a polarizing optical microscope, micromolar levels of LCA in aqueous solution can be detected. The detection limit and selectivity of surfactant-stabilized 5CB droplets for LCA depend on the chain length and headgroup of the surfactants used for stabilizing 5CB droplets.

Citation

Tanmay Bera, Jiyu Fang. Optical detection of lithocholic acid with liquid crystal emulsions. Langmuir : the ACS journal of surfaces and colloids. 2013 Jan 8;29(1):387-92