Macromolecular Crowding as an Intracellular Stimulus for Responsive Nanomaterials.
Daniel A Estabrook, John O Chapman, Shuo-Ting Yen, Helen H Lin, Ethan T Ng, Linglan Zhu, Heidi L van de Wouw, Otger Campàs, Ellen M Sletten
Author Information
Daniel A Estabrook: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States. ORCID
John O Chapman: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States. ORCID
Shuo-Ting Yen: Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States. ORCID
Helen H Lin: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States.
Ethan T Ng: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States.
Linglan Zhu: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States.
Heidi L van de Wouw: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States. ORCID
Otger Campàs: Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States.
Ellen M Sletten: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States. ORCID
Stimuli-responsive materials are exploited in biological, materials, and sensing applications. We introduce a new endogenous stimulus, biomacromolecule crowding, which we achieve by leveraging changes in thermoresponsive properties of polymers upon high concentrations of crowding agents. We prepare poly(2-oxazoline) amphiphiles that exhibit lower critical solution temperatures (LCST) in serum above physiological temperature. These amphiphiles stabilize oil-in-water nanoemulsions at temperatures below the LCST but are ineffective surfactants above the LCST, resulting in emulsion fusion. We find that the transformations observed upon heating nanoemulsions above their surfactant's LCST can instead be induced at physiological temperatures through the addition of polymers and protein, rendering thermoresponsive materials "crowding responsive." We demonstrate that the cytosol is a stimulus for nanoemulsions, with droplet fusion occurring upon injection into cells of living zebrafish embryos. This report sets the stage for classes of thermoresponsive materials to respond to macromolecule concentration rather than temperature changes.
References
Nat Commun. 2019 Jun 21;10(1):2749
[PMID: 31227703]
