Interfacial Complexation Induced Controllable Fabrication of Stable Polyelectrolyte Microcapsules Using All-Aqueous Droplet Microfluidics for Enzyme Release

Abstract

Water-in-water (w/w) emulsions are particularly advantageous for biomedical-related applications, such as cell encapsulation, bioreactors, biocompatible storage, and processing of biomacromolecules. However, due to ultralow interfacial tension, generation and stabilization of uniform w/w droplets are challenging. In this work, we report a strategy of creating stable and size-controllable w/w droplets that can quickly form polyelectrolyte microcapsules (PEMCs) in a microfluidic device. A three-phase (inner, middle, outer) aqueous system was applied to create a stream of inner phase, which could be broken into droplets via a mechanical perturbation frequency, with size determined by the stream diameter and vibration frequency. The interfacial complexation i s f o r m e d v i a e l e c t r o s t a t i c i n t e r a c t i o n o f p o l y c a t i o n s o f p o l y -(diallyldimethylammoniumchloride) with polyanions of polystyrene sodium sulfate in the inner and outer phases. With addition of negatively charged silica nanoparticles, the stability, permeability, and mechanical strength of the PEMC shell could be well manipulated. Prepared PEMCs were verified by encapsulating fluorescein isothiocyanate-labeled dextran molecules and stimuli-triggered release by varying the pH value or osmotic pressure. A model enzyme, trypsin, was successfully encapsulated into PEMCs and released without impairing their catalytic activity. These results highlight its potential applications for efficient encapsulation, storage, delivery, and release of chemical, biological, pharmaceutical, and therapeutic agents.

An open-source handheld extruder loaded with pore-forming bioink for in situ wound dressing

“…the aqueous two-phase emulsion system, when the two aqueous phases used are meticulously selected [ 41 , 42 ]. As such, it has been demonstrated that it was possible to directly write [ 43 ] or print [ 44 ] an aqueous pattern within another aqueous bath, or produce droplets using microfluidic devices [ [45] , [46] , [47] , [48] , [49] ]. The unique advantage of biocompatibility of the aqueous two-phase emulsion system allows it to be used in the presence of cells without exerting any toxicity otherwise imposed by the organic solvents in conventional emulsions.…”

Droplet Microfluidics for Tumor Drug‐Related Studies and Programmable Artificial Cells

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Facile Preparation and Excellent Ultraviolet Shielding Application of Polyurethane‐TiO2 Composite Microcapsules

“…Microcapsule technology has many characteristics such as strong protection, easy storage, and controlled release. [11][12][13][14] Phase change materials can be coated in solid outer wall materials through microencapsulation technology, which can not only solve its application defects but also play a certain protective role. In addition, it has important applications in industry, agriculture, manufacturing, and the military.…”