title: Optical visualization and quantification of enzyme activity using dynamic droplet lenses.
abstract: In this paper, we describe an approach to measuring enzyme activity based on the reconfiguration of complex emulsions. Changes in the morphology of these complex emulsions, driven by enzyme-responsive surfactants, modulate the transmission of light through a sample. Through this method we demonstrate how simple photodetector measurements may be used to monitor enzyme kinetics. This approach is validated by quantitative measurements of enzyme activity for three different classes of enzymes (amylase, lipase, and sulfatase), relying on two distinct mechanisms for coupling droplet morphology to enzyme activity (host-guest interactions with uncaging and molecular cleavage).
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139.|Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA 02139.
authors.forename: Lauren D
authors.initials: LD
authors.lastname: Zarzar
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139.|Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA 02139.
authors.forename: Julia A
authors.initials: JA
authors.lastname: Kalow
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139.|Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA 02139.
authors.forename: Xinping
authors.initials: X
authors.lastname: He
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139.|Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA 02139.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Walish
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139; tswager@mit.edu.|Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA 02139.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Swager
mesh_terms: D000681:Amylases / Q000378:metabolism*; D001230:Aspergillus / Q000201:enzymology; D002175:Candida / Q000201:enzymology; D004655:Emulsions; D007700:Kinetics; D008049:Lipase / Q000378:metabolism*; D044085:Microfluidics / Q000295:instrumentation*; D055095:Optics and Photonics; D013429:Sulfatases / Q000378:metabolism*; D013501:Surface-Active Agents
chemical_list: D004655:Emulsions; D013501:Surface-Active Agents; D008049:Lipase; D013429:Sulfatases; D000681:Amylases
keywords: assay; emulsion; enzyme; lenses; sensor