Technology for Anisotropic Particles

With the increasing number of interesting applications of anisotropic microparticles, the technology that can be used for anisotropic microparticles has been of great importance. We developed a new replica molding technique called as degassed micromold lithography (DML) that allows for the rapid fabrication of anisotropic hydrogel microparticles with high-resolution and high uniformity. The existing replica molding techniques are limited in their ability to synthesize a narrow range of particle compositions and shapes because of the difficulty in loading precursors into the micromolds as well as the low particle homogeneity due to the uneven evaporation of the precursors. Our DML technique is based on the gas-solubility of a degassed micromold that acts as a suction pump to fill the mold by drawing precursor liquids in. The semi-closed system within the micromold prevents the uneven evaporation of the precursor, which is essential for the production of homogeneous particles. Furthermore, controlled uniformity of the hydrogel microparticles can be achieved by engineering the design of the micromold array. Using this synthesis platform, we are interested in developing microparticles for biomedical applications.

Droplet based-microfluidics has a lot of potential to integrate interdisciplinary field of research combining soft matter physics, chemical engineering, microsystems engineering, biomedical engineering. In the droplet-based microfluidics, monodisperse emulsion can be generated in large quantities of which size can be precisely controlled by manipulating the operation parameter. Due to their uniform size distribution, each droplet can be used as a chemical batch and a carrier for delivering chemical compounds or living things. In our lab, we focused on the biomedical research using microfluidic process such as cell delivery and drug delivery.

Flow lithography (FL) invented by Doyle group in MIT is a powerful synthesis technique that enables the fabrication of microparticles with geometrical and chemical patterns. Microfluidic methods provide a flexible toolset for patterning precursor liquids in the synthesis process. Complex laminar flow patterns can easily be established in microfluidic channels without the need for physical separators. FL is a versatile technique that combines photolithography with the capabilities of microfluidic methods for the high-fidelity synthesis of a wide range of complex gel microparticles. In this technique, photomask-defined shapes can be rapidly printed onto structured micro-flows, providing precise control over particle size, geometry, and chemical patchiness. We utilize the FL techniques to synthesize novel functional particles for a wide range of applications.