UCLA

Understanding cellular heterogeneity is a crucial part of modern biomedical research as well as medical diagnostics and therapeutics. A multitude of technologies have emerged to perform single cell measurements, but low throughput and high cost remain barriers to largescale adoption. This dissertation discusses the development of three single cell techniques that enable new measurement modalities in addition to improving throughput. Two of the described technologies are label-free assays, measurements that do not require molecular labels and as a result, are cheaper, faster, and less invasive ways of measuring cell state.

Chapter 1 discusses the importance of single cell measurements and the benefits of label-free assays. Chapter 2 discusses Multiparameter Deformability Cytometry, a label-free technique to measure the physical properties of cells. This technique builds upon previous deformability cytometry work by extending measurement capabilities to include cellular morphology and deformation kinetics. We demonstrate the usefulness of the new system by measuring and classifying stem cells and their descendants based on mechanical phenotype alone. Chapter 3 discusses the development of a parallel flow cytometer. By integrating an ultrafast fluorescence imaging technology with a novel microfluidic flow cell, we are able to increase sample throughput by interrogating up to eight samples simultaneously. Chapter 4 describes a technology that bridges the gap between conventional biomolecular measurements and physical phenotype measurements. By once again integrating an ultrafast imaging technique with a novel microfluidic flow cell, we can perform simultaneous biochemical and physical measurements on single cells. Additionally, by staining subcellular structures, we can begin to investigate the mechanical properties of cellular components such as the nucleus. We demonstrate the capabilities of the system by measuring the deformability of cells after treatment with various cytoskeletal agents as well as by osmotically shocking cells and observing changes to their nuclear and cytoplasmic deformations.