High-Throughput Fabrication of Size-Controlled Pickering Emulsions, Colloidosomes and Air-Coated Particles via Clog-Free Jetting of Suspensions.

Microcapsules with a liquid core and a solid shell composed of hydrophobic nanoparticles are broadly applied in food, pharmaceutics, and biotechnologies. For example, Pickering emulsions, colloidosomes, or antibubbles (droplets surrounded by air layers in water) enable the controlled release of active agents, biocompatibility, and contact-less liquid transportation. However, producing controlled nanoparticle-or polymer-laden hydrophobic shells at scale is highly challenging, since bulk methods are polydisperse and droplet-based methods such as microfluidic chips are prone to clogging and slow. Here we show clog-free coating of an aqueous jet with silica nanoparticle suspensions with concentrations up to 10% (w/v) as well as high concentrations of polymers (30% (w/v) poly(lactic acid)), enabling continuous generation of microcapsules at flow rates up to 4 mL/min. Pickering emulsions were converted into capsules, providing hydrophobic shells consisting of nanoparticles for controlled release. As a highlight, we demonstrate the scalable fabrication of air-coated capsules (antibubbles) in the sub-mm range. The shell contains an air film that protects the liquid core for days yet enables ultrasound-induced release within 3 minutes. By enabling rapid fabrication of controlled Pickering emulsions, colloidosomes, antibubbles, and biodegradable capsules, jetting through a liquid layer (JetALL) provides a versatile platform for advanced applications in food, pharmacy, and life science. This article is protected by copyright. All rights reserved.