Congrats, Dr. Keepseagle & Dr. Kim!

Congrats, Dr. Keepseagle & Dr. Kim!

May 31, 2024

Kayla & Seongsoo have successfully defended their thesis! Congrats to both of them!

Title of Kayla’s thesis: Microfluidic Technologies to Advance Antibody Discovery
Abstract: This dissertation introduces a pioneering approach to antibody discovery that harnesses the power of advanced microfluidic technology. Our innovative methodology revolves around the isolation of singular antibody-producing B-cells, a feat accomplished through the encapsulation of individual B-cells and an oligo-dT gel within microdroplets. This cutting-edge technique enables the targeted capture of a single type of antibody, thereby streamlining the discovery process. Leveraging microfluidic systems, we have meticulously designed a microenvironment conducive to encapsulating a solitary B-cell alongside the oligo-dT gel. The microdroplets function as miniature reaction vessels, providing an isolated setting for antibody synthesis and capture. This microscale strategy not only enhances efficiency but also minimizes sample requirements. Furthermore, we have employed state-of-the-art DNA sequencing techniques to meticulously analyze and characterize the antibody library resulting from our microfluidic-assisted capture. The comprehensive DNA sequencing results have furnished invaluable insights into the diversity and specificity of the isolated antibodies. The pivotal findings of this research underscore the potential of our microfluidic-assisted method for expeditious and precise antibody discovery. By capturing antibodies at the single B-cell level, we have ushered in a new era of possibilities for generating targeted and highly specific antibodies. This work serves as a significant contribution to the advancement of antibody engineering and lays the groundwork for the development of therapeutic agents boasting enhanced efficacy and precision.

Title of Seongsoo’s thesis: Plastic Deformation and Work Hardening of Colloidal Crystals.

Here is part of his thesis:

When a crystal is stressed beyond a certain value (the yield strength), it exhibits plastic flow, which causes an irreversible change in its shape. As plastic flow progresses, increasingly large flow stresses are needed, a phenomenon called work hardening. Although it has been established for decades that plastic flow in crystals is governed by the nucleation and motion of line defects (dislocations), a full understanding of plastic deformation and work hardening remains to be developed due to the complex nature of the networks formed by the dislocations. Our ability to observe the exact interaction mechanism experimentally is limited by the difficulty of visualizing dislocation dynamics. Electron microscopy is the tool of choice, but in situ observations of the collective dynamics of dislocations during work hardening have so far remained out of experimental reach.

Colloidal crystals are uniquely suited for such an experiment since the micrometer size of the particles allows imaging of the three-dimensional structure of the crystal in the single particle resolution and in real-time. We use high-speed confocal imaging to visualize the crystals in-situ during plastic deformation and record both stress and strain, as well as the evolution of the three-dimensional dislocation networks.

This thesis reports experimental studies of two deformation processes of colloidal crystals: shear deformation and plastic relaxation during epitaxial growth. Both studies not only provide important insights into the nature of plastic deformation and work hardening in general, but also reveal remarkable aspects of hard-sphere colloidal crystals.