A novel, planar, microfluidic junction for multiphase flow,
exemplified through the production of fusion energy targets,
encapsulated mouse neuron stem cells and multi-compartmental capsules
Droplet microfluidics has been extensively studied in last two decades and found various applications in diverse research fields. In this thesis, we focused on the
development of planar microfluidic devices, and explored their utility for the formation of multiple emulsions and microparticle fabrication. Here, a geometry variant flow-focusing junction was exhibited to control the location position of droplet breakup, and eliminate the satellite droplets. Then, this junction was tested to form monodispersed, multi-cored, double-emulsion droplets with controllable core numbers (up to 35) in a stepwise emulsification mechanism. Based on the above device, three diverse applications of droplet microfluidics have been conducted: (1) the mass fabrication of polymeric microcapsules with high sphericity and concentricity for inertial confinement fusion (ICF) target fabrication;
(2) the production of microgels to encapsulate mouse neuron stem cells for stem cell therapy in the treatment of spinal cord injury; and (3) the formation of squalene droplets with motility and encapsulated droplet interface bilayers for the ultimate creation of artificial cells.
Through the above, the following was achieved: (1) Single-core water/polymer/oil double emulsion droplets, as ICF target shells (for which sphericity and concentricity are paramount), were produced at tunable rates up to 20Hz. The
polymeric microcapsules were solidified by using photopolymerization (minimum ultra violet exposure duration is 30ms) with an average 98.43±0.68% sphericity (best
99.69%), an average 98.44±0.62% concentricity (best 99.72%) and 100% yield rate; (2) Mouse neuron stem cells were encapsulated in alginate microspheres at 1 million cells/mL alginate. MTT assays were conducted to provide evidence that the cells survived the encapsulation process with continuous proliferation in vitro; and (3) xxviii
Various arrangements of encapsulated droplet interface bilayer network were observed, and the motility of double emulsion droplets was realized by continuous
interfacial reactions, through which the expulsion and capture actions of squalene droplets were identified
