Fireflies-On-A-Chip: (Ionic Liquid)-Aqueous Microdroplets for Biphasic Chemical Analysis

Inspired by the enchanting bioluminescence of fireflies, herein microfluidic droplet‐based ‘fireflies’ for non‐invasive biphasic chemical analysis are demonstrated. Bicompartmental droplets are created where a model analyte is transported from the aqueous compartment to the adjacent ionic liquid segment, yielding a bright fluid firefly structure via a localized catalytic reaction. Analysis of fluorescence emission kinetics and a method to passively decouple the two compartments at a constriction are presented.