Spontaneous Sequestration of Proteins into Liquid Crystalline Microdroplets

In this work a facile method for fabricating protein-sequestered liquid crystal (LC) emulsion droplets based on the uptake of surface-engineered protein–polymer surfactant (PS) core–shell bioconjugates is described. Uptake of myoglobin-PS, bovine serum albumin-PS, Zn-porphyrin myoglobin-PS, horseradish peroxidase-PS, and glucose oxidase-PS occurs without structural or functional degradation, and gives rise to sequestration within the interior or at the surface of 4-cyano-4′-pentylbiphenyl (5CB) nematic droplets depending on the surface modification of the protein-PS bioconjugates. Differences in uptake behavior are used to achieve the spontaneous positional assembly of multiple proteins in the LC phase, and the use of spatially separated glucose oxidase-PS and horseradish peroxidase-PS bioconjugates is demonstrated to produce 5CB based droplets capable of housing an enzyme cascade reaction. This method opens a pathway for the development of bioactive liquid crystal droplets and can have potential applications in the optical sensing of biomolecular substrates.