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.