Research ArticleMATERIALS SCIENCE

Nanocomposite capsules with directional, pulsed nanoparticle release

See allHide authors and affiliations

Science Advances  08 Dec 2017:
Vol. 3, no. 12, eaao3353
DOI: 10.1126/sciadv.aao3353

You are currently viewing the abstract.

View Full Text

Abstract

The precise spatiotemporal delivery of nanoparticles from polymeric capsules is required for applications ranging from medicine to materials science. These capsules derive key performance aspects from their overall shape and dimensions, porosity, and internal microstructure. To this effect, microfluidics provide an exceptional platform for emulsification and subsequent capsule formation. However, facile and robust approaches for nanocomposite capsule fabrication, exhibiting triggered nanoparticle release, remain elusive because of the complex coupling of polymer-nanoparticle phase behavior, diffusion, phase inversion, and directional solidification. We investigate a model system of polyelectrolyte sodium poly(styrene sulfonate) and 22-nm colloidal silica and demonstrate a robust capsule morphology diagram, achieving a range of internal morphologies, including nucleated and bicontinuous microstructures, as well as isotropic and non-isotropic external shapes. Upon dissolution in water, we find that capsules formed with either neat polymers or neat nanoparticles dissolve rapidly and isotropically, whereas bicontinuous, hierarchical, composite capsules dissolve via directional pulses of nanoparticle clusters without disrupting the scaffold, with time scales tunable from seconds to hours. The versatility, facile assembly, and response of these nanocomposite capsules thus show great promise in precision delivery.

This is an open-access article distributed under the terms of the Creative Commons Attribution license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

View Full Text