TY - JOUR
T1 - Microfluidic Formation of Hydrogel Microcapsules with a Single Aqueous Core by Spontaneous Cross-Linking in Aqueous Two-Phase System Droplets
AU - Watanabe, Takaichi
AU - Motohiro, Ibuki
AU - Ono, Tsutomu
N1 - Funding Information:
We are grateful for financial support from Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research (KAKENHI) [Grant-in-Aid for Young Scientists (B) 16K20985]. The authors gratefully thank Division of Instrumental Analysis, Department of Instrumental Analysis & Cryogenics, Advanced Science Research Center, Okayama University for the use of the confocal laser scanning microscope.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/2/12
Y1 - 2019/2/12
N2 - We report a simple process to fabricate monodisperse tetra-arm poly(ethylene glycol) (tetra-PEG) hydrogel microcapsules with an aqueous core and a semipermeable hydrogel shell through the formation of aqueous two-phase system (ATPS) droplets consisting of a dextran-rich core and a tetra-PEG macromonomer-rich shell, followed by a spontaneous cross-end coupling reaction of tetra-PEG macromonomers in the shell. Different from conventional techniques, this process enables for the continuous production of hydrogel microcapsules from water-in-oil emulsion droplets under mild conditions in the absence of radical initiators and external stimuli such as heating and ultraviolet light irradiation. We find that rapid cross-end coupling reaction of tetra-PEG macromonomers in ATPS droplets in the range of pH from 7.4 to 7.8 gives hydrogel microcapsules with a kinetically arrested core-shell structure. The diameter and core-shell ratio of the microcapsules can be easily controlled by adjusting flow rates and ATPS compositions. On the other hand, the slow cross-end coupling reaction of tetra-PEG macromonomers in ATPS droplets at pH 7.0 and lower induces structural change from core-shell to Janus during the reaction, which eventually forms hydrogel microparticles with a thermodynamically stable crescent structure. We believe that these hydrogel microparticles with controlled structures can be used in biomedical fields such as cell encapsulation, biosensors, and drug delivery carriers for sensitive biomolecules.
AB - We report a simple process to fabricate monodisperse tetra-arm poly(ethylene glycol) (tetra-PEG) hydrogel microcapsules with an aqueous core and a semipermeable hydrogel shell through the formation of aqueous two-phase system (ATPS) droplets consisting of a dextran-rich core and a tetra-PEG macromonomer-rich shell, followed by a spontaneous cross-end coupling reaction of tetra-PEG macromonomers in the shell. Different from conventional techniques, this process enables for the continuous production of hydrogel microcapsules from water-in-oil emulsion droplets under mild conditions in the absence of radical initiators and external stimuli such as heating and ultraviolet light irradiation. We find that rapid cross-end coupling reaction of tetra-PEG macromonomers in ATPS droplets in the range of pH from 7.4 to 7.8 gives hydrogel microcapsules with a kinetically arrested core-shell structure. The diameter and core-shell ratio of the microcapsules can be easily controlled by adjusting flow rates and ATPS compositions. On the other hand, the slow cross-end coupling reaction of tetra-PEG macromonomers in ATPS droplets at pH 7.0 and lower induces structural change from core-shell to Janus during the reaction, which eventually forms hydrogel microparticles with a thermodynamically stable crescent structure. We believe that these hydrogel microparticles with controlled structures can be used in biomedical fields such as cell encapsulation, biosensors, and drug delivery carriers for sensitive biomolecules.
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U2 - 10.1021/acs.langmuir.8b04169
DO - 10.1021/acs.langmuir.8b04169
M3 - Article
C2 - 30626189
AN - SCOPUS:85061403093
VL - 35
SP - 2358
EP - 2367
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 6
ER -