SUBJECT: Ph.D. Proposal Presentation
BY: Fangyuan Zhou
TIME: Wednesday, November 18, 2015, 2:00 p.m.
TITLE: Developing microfluidic platforms for adhesion kinetics study and specific cell sorting
COMMITTEE: Dr. Cheng Zhu, Co-Chair (BME/ME)
Dr. Hang Lu, Co-Chair (CHBE)
Dr. Susan Thomas (ME)
Dr. Todd Sulchek (ME)
Dr. Wilbur Lam (BME)


Cell adhesion mediates a number of cellular functions including the initiation of leukocyte immune responses and platelet adhesion. Cell adhesion by receptor-ligand interactions of molecules anchored on cell surface and the other molecules on the matrix or other cells are termed two-dimensional (2D) kinetics. In-depth study of adhesion kinetics requires single-cell measurement in a relatively large population, considering the heterogeneity of cells. In addition, a great number of adhesion processes involve sequential engagements of multiple ligand-receptor systems. However, current single-cell techniques such as optical tweezer and atomic force microscopy have limitations like intense labor, low throughput, and limited ligand presentation. Lacking population study makes it statistically difficult to form conclusions. Besides, precise control of molecule contact is required for kinetics and adhesion memory assessment, which is unlikely to achieve in conventional assays like flow chamber. Moreover, specific T cells usually need to be sorted from polyclonal population or blood for basic research or immune counting. However, conventional optical ways is limited by spectral overlap for signaling and adhesion level interrogating. Some non-labeling microfluidic assays, nevertheless, have a low recovery rate (<20%) and is limited for rare cell sorting.
This thesis will aim to develop microfluidic platforms to 1) sequentially measure multiple ligand binding strengths of cells upon triggering by multi-step interaction for hundreds of cells at single-cell level; 2) realize high-throughput binding kinetics characterization via multi-measurement parallelization. In advance, the ability of distinguishing cell adhesion signatures from previous two projects will be utilized for inventing a microfluidic platform that sorts specific cells of certain binding avidity. Furthermore, a sorting system will be established for T cells targeting tumor with unidentified antigens.
This work is innovative as it provides new assays to study molecular sequences and kinetics in cell activation. Moreover, it provides an assay to sort specific T cells from polyclonal cells towards unknown ligands of target cells, which may inspire new methods on personalized patients’ treatments.