Microfluidic production of biopolymer microcapsules with controlled morphology.
We report a microfluidic approach to generating capsules of biopolymer hydrogels. Droplets of an aqueous solution of a biopolymer were emulsified in an organic phase comprising a cross-linking agent. Polymer gelation was achieved in situ (on a microfluidic chip) by diffusion-controlled ionic cross-linking of the biopolymer, following the transfer of the cross-linking agent from the continuous phase to the droplets. Gelation was quenched by collecting particles in a large pool of cross-linking agent-free liquid. The structure of microgels (from capsules to gradient microgels to particles with a uniform structure) was controlled by varying the time of residence of droplets on the microfluidic chip and the concentration of the cross-linking agent in the continuous phase. We demonstrated the encapsulation of a controlled number of polystyrene beads in the microgel capsules. The described approach was applied to the preparation of capsules of several polysaccharides such as alginate, kappa-carrageenan, and carboxymethylcellulose.
Zhang
Hong
H
Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.
Tumarkin
Ethan
E
Peerani
Raheem
R
Nie
Zhihong
Z
Sullan
Ruby May A
RM
Walker
Gilbert C
GC
Kumacheva
Eugenia
E
D002214:Capsules; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry*; D044085:Microfluidics / Q000379:methods*; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D011134:Polysaccharides / Q000138:chemical synthesis / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*
D002214:Capsules; D020100:Hydrogels; D011134:Polysaccharides; D011137:Polystyrenes