Utilizing Geometrically and Chemically Anisotropic Particles for Biomedical Applications

Flow lithography (FL) pioneered by the Doyle group in MIT has been a powerful synthesis technique that enables the mass-production of hydrogel microparticles with geometrical and chemical patterns. The technique combines photolithography with microfluidic methods, providing precise control over shape and chemical patchiness in particles. Much of my PhD works has been focused on the development of advanced flow lithography that can achieve much higher degree of geometrical and chemical complexity in particles than before. Briefly, my techniques can be used to create hydrogel particles with 3D morphologies and chemical patterns. Also, I have extended the process of FL to non-PDMS based channels (ex. glass or plastic channels), and prepared novel class of functional particles using water insoluble monomers, organic solvents, and hydrophobic functional entities such as quantum dots, ruthenium dyes, and single-walled carbon nanotubes.

One of the powerful advantages of the anisotropic multifunctional hydrogel particles prepared by FL is that the particles are very well-suited for the biomedical applications. Typically, the gel particles are synthesized from monomers based on polyethylene glycol which is bio-friendly, highly tunable, and can be functionalized with a variety of biomolecules. Also, the controlled shapes and chemical patterns in particles can provide unique function for applications in diagnosis, treatment, and tissue engineering. For example, multifunctional barcoded particles have been designed for the rapid screening of target biomolecules in a complex biological mixture. Another example can be the artificial red blood cells (RBCs). Recently, soft disk particles with a few micron dimensions were synthesized to mimic RBCs, exhibiting the reversible deformability which is the vital property to allow RBCs to function.

In this presentation, I summarize the previous works, introduce current works that use the particle technology to do research on cell motility with applications to clinical cancer research as well as the separation of circulating tumor cells, and emphasize the importance of future works to bridge the particle technology to the biomedical area.

Selected Publications (* denotes co-first author status)

Bong KW, Xu JJ, Kim JH, Chapin SC, Strano MS, Gleason KK, Doyle PS. Non-polydimethylsiloxane Devices for Oxygen-Free Flow Lithography. Nature Communications, 2012, 3, 805.

Bong KW*, Chapin SC*, Pregibon DC, Baah D, Floyd-Smith TM, Doyle PS. Compressed-air Flow Control System. Lab Chip, 2011, 11(4): 743-747.

Suh SK*, Bong KW*, Hatton TA, Doyle PS. Using Stop-Flow Lithography to Produce Opaque Microparticles: Synthesis and Modeling. Langmuir, 2011, 27(22):13813-13819.

Bong KW, Bong KT, Pregibon DC, Doyle PS. Hydrodynamic Focusing Lithography. Angew. Chem. Int. Ed., 2010, 49(1): 87-90.

Bong KW, Chapin SC, Doyle PS. Magnetic Barcoded Hydrogel Microparticles for Multiplexed Detection. Langmuir, 2010, 26(11): 8008-8014.

Bong KW, Pregibon DC, Doyle PS. Lock release lithography for 3D and composite microparticles. Lab Chip, 2009, 9(7): 863-866.