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Title: Facile microfluidic production of composite polymer core-shell microcapsules and crescent-shaped microparticles
Authors: Ekanem, Ekanem E.
Zhang, Zilin
Vladisavljevic, Goran T.
Keywords: Biodegradable polymers
Core-shell microcapsules
Cell encapsulation
Crescent particles
Ionic gelation
Issue Date: 2017
Publisher: Elsevier © The Authors
Citation: EKANEM, E.E., ZHANG, Z. and VLADISAVLJEVIC, G.T., 2017. Facile microfluidic production of composite polymer core-shell microcapsules and crescent-shaped microparticles. Journal of Colloid and Interface Science, 498, pp. 387-394.
Abstract: Hypothesis: Core-shell microcapsules and crescent-shaped microparticles can be used as picolitre bioreactors for cell culture and microwells for cell trapping/immobilisation, respectively. Results: Monodisperse polylactic acid (PLA) core-shell microcapsules with a diameter above 200 lm, a shell thickness of 10 lm, and 96% water entrapment efficiency were produced by solvent evaporation from microfluidically generated W/O/W emulsion drops with core-shell structure, and used to encapsulate Saccharomyces cerevisiae yeast cells in their aqueous cores. The morphological changes of the capsules stained with Nile red were studied over 14 days under different osmotic pressure and pH gradients. Findings: The shell retained its integrity under isotonic conditions, but buckling and particle crumbling occurred in a hypertonic solution. When the capsules containing 5 wt% aqueous Eudragit S 100 solution in the core were incubated in 10 4 M HCl solution, H+ diffused through the PLA film into the core causing an ionic gelation of the inner phase and its phase separation into polymer-rich and water-rich regions, due to the transition of Eudragit from a hydrophilic to hydrophobic state. Crescent-shaped composite microparticles with Eudragit cores and PLA shells were fabricated by drying core-shell microcapsules with gelled cores, due to the collapse of PLA shells encompassing water-rich crescent regions.
Description: This article was published as Open Access by Elsevier under the CC BY 4.0 licence (https://creativecommons.org/licenses/by/4.0/).
Sponsor: E.E.E. holds a scholarship from Niger Delta Development Commission (NDDC), Nigeria. The authors gratefully acknowledge the financial support from the EPSRC – United Kingdom grant EP/HO29923/1 and the assistance of Scott Doak from the Loughborough Materials Characterisation Centre for the FIB imaging.
Version: Published version
DOI: 10.1016/j.jcis.2017.03.067
URI: https://dspace.lboro.ac.uk/2134/24633
Publisher Link: http://dx.doi.org/10.1016/j.jcis.2017.03.067
ISSN: 0021-9797
Appears in Collections:Published Articles (Chemical Engineering)

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