Dynamic Hybrid Colloidosomes via Electrostatic Interactions for pH-Balanced Low Premature Leakage and Ultrafast Cargo Release.

A trade-off between minimized premature leakage and rapid cargo release on demand is an intractable obstacle faced by smart delivery systems that restrains them from lab to market. To address this dilemma, dynamic hybrid colloidosomes relying on strong yet reversible electrostatic interactions are developed, simply through one-pot cooperative self-assembly of silica nanoparticles and fluorescent carbon dots at the interface of emulsion droplets. Specifically, pH-driven charge reversal of zwitterionic carbon dots leads to immediate electrostatic conversion between the two building blocks from attraction to repulsion. This makes robust locking and instantaneous breakdown of the colloidosomes subtly balanced, thus enabling low off-state leakage (10.5% over 7 days) while ultrafast on-state release (>90% within 5 min) upon an acidic stimulus. We envision that such biocompatible, traceable, and smart colloidosomes will offer unique opportunities for broad applications as on-demand release is desired.