Event

PhD Dissertation Defense Announcement: Eric Esch

Tuesday, July 7, 2026
10:00 a.m.
AJC 4104 (4th floor conference room)
Debbie Chu
301 405 8268
dgchu@umd.edu

Title: Improved Technology for Time Domain Measurements in Flow Cytometry

Committee members:
Dr. Gregory Cooksey, Co-Chair
Dr. Ian White, Co-Chair
Dr. Alisa Clyne
Dr. John Fisher
Dr. Don DeVoe, Dean's Representative

Abstract:
Flow cytometers that repeat measurements on single cells are powerful tools enabling uncertainty quantification and other fundamentally new strategies in cytometry. While this approach introduces new testing modes in cytometry, multi-region measurements in these systems increase hardware complexity and conventionally constrain measurement timescales. This dissertation addresses both problems by developing new microengineered multiple-region flow cytometers and validation strategies for testing them.

In one subproject, to reduce the bulk, complexity and cost of repeated measurement regions, amplitude modulation of illumination lasers with discrete carrier frequencies was used to encode the location of flow cytometric pulses in a multi-region single-photodetector flow cytometer. The system was validated with a pair of integrated in-line ground truth detectors and showed uncertainty quantification performance equivalent to prior work. Another subproject developed systems for kinetic cytometry, in which a series of measurements were made over tens of milliseconds to tens of seconds to examine dynamic responses in cells to microenvironmental stimuli such as the introduction of soluble factors. As proofs-of-concept, two optofluidic kinetic cytometers were built and validated with tests of membrane permeabilization of Jurkat cells by detergent in solution.

Significantly, the instruments developed herein permitted repeat measurements with simple hardware configurations, or with shiftable timescales at a range of flow speeds to enable analysis of kinetics of cells’ responses to soluble stimulus, two outcomes which are not possible with prior multi-region flow cytometers. These new capabilities will support the possibility of a kinetic cytometer designed to predict the fitness of therapeutically engineered cells (e.g., CAR T cells) by their immediate internal signaling responses to programming stimulus. These two projects, both adding to the capabilities of multiple-region flow cytometry with time-domain improvements, should help expand and support the growing fields of biomanufacturing, immunotherapeutics, and biomedical research.