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Transformable bubble-filled alginate microfibers via vertical microfluidics

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)851-863
Number of pages13
Issue number5
Early online date16 Jan 2019
Accepted/In press15 Jan 2019
E-pub ahead of print16 Jan 2019
PublishedJan 2019


King's Authors


A novel buoyancy-assisted vertical microfluidic setup has been developed to fabricate a new class of transformable bubble-filled hydrogel microfibers. A co-axial flow of an aqueous sodium-alginate solution enveloping an air phase was injected into a quiescent aqueous CaCl2 solution, through a vertically-oriented co-axial glass-capillary setup. This induced an instantaneous gelation and produced bubble-filled calcium-alginate fibers. The surface-morphology of resulting fibers was controlled from smooth to wavy by slowing down the gelation kinetics. Advantage of the buoyancy force acting on the fibers by the trapped air bubbles was taken not only to shape the fibers, but to transform them into several other novel hydrogel structures, such as water-filled segmented fibers, beaded microfibers, and threaded capsules. The ultimate transformability was demonstrated by the fibers being allowed to elongate and then undergo a controlled destruction to produce uniform anisotropic micro-particles with wide range of sizes and shapes from frustums to barrel and cylindrical types.

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