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Gregory A Cooksey (Fed)

Microfluidic cytometer
Microfluidic cytometer with integrated optical fibers (blue) that delivery light to and collect light from multiple interrogation regions inside the chip.

Dr. Cooksey’s laboratory at NIST focuses on creating microfluidic tools to improve measurements and enable discoveries in biomedical and clinical research.   His group is developing new approaches to measure optical properties of cells and materials in flow, and applications related to cytometry.

The group recently published the first direct uncertainty measurements in flow cytometry, which required novel flow control and analysis techniques in microfluidic devices with integrated waveguides.  Work with collaborators in the Information Technology Laboratory is using signals analysis to improve counting, classification, and understanding of physical properties (e.g. size and shape) of objects in flow.  

The team continues to improve accurate measurements of volumetric flow rates, recently demonstrating dynamic measurements of 1 nL/min with 5 % uncertainty and limit of detection of about 10 pL/min.  The technique involves linking fluorescent properties of materials to the dosage of light they receive while flowing through an optical interrogation region. 

These projects are part of the NIST on a Chip program and are supported by a NIST Innovation in Measurement Science (IMS) award.

Greg Cooksey joined NIST in 2007 as a National Research Council postdoctoral fellow and is a biomedical engineer and Project Leader in the Microsystems and Nanotechnology Division.  Prior to NIST he was a graduate student and postdoctoral researcher at the University of Washington, where he developed surfaces and devices to study migrating cells and neurons.

Member Of


Research Opportunities Available

lab on a chip cover

Potential Research Topics include:

  • Optofluidic cytometry design and characterization
  • Flow metrology; picoliter per minute measurements and dynamics
  • Microdroplet packaging and measurement
  • Cell-based microfluidic assays/diagnostics
  • Physical modeling, e.g. of dynamic systems in flow
  • Design of novel microfluidic functionalities

We encourage interested post-doctoral and graduate research candidates to contact us to discuss project opportunities and fellowships.  

Click here to go to our project listing with the National Research Council (NRC) 

Click here to find out how to apply for an NRC Postdoctoral Fellowship

Summer research opportunities for undergraduates (SURF Program) and high school students (SHIP Program) may also be available.  

Please contact me for more details or to discuss other ways to work together.

Selected Publications


Matching and comparing objects in a serial cytometer

Nikita Podobedov, Matthew DiSalvo, Jason A. Hsu, Paul Patrone, Gregory A. Cooksey
Flow cytometers are indispensable for clinical studies, yet are hindered by inherent uncertainties. We have developed an optofluidic device capable of multiple

Patents (2018-Present)

Serial Cytometry

NIST Inventors
Gregory A Cooksey , Paul Patrone and Anthony J. Kearsley
Flow cytometers can make thousands of single-cell measurements per second, but the limited ability to quantify uncertainty in individual measurements reduces their effectiveness for characterizing biomarker distributions, discriminating cell populations, and detecting rare events. To facilitate

Multiplexed Amplitude Modulation Fluorometry

NIST Inventors
Anthony J. Kearsley , Gregory A Cooksey and Paul Patrone
Improving accuracy of cytometers is challenging because optical configuration, flow control methods, and calibration issues make it difficult to characterize geometric factors associated with signal collection. State-of-the-art tools only collect a small solid angle of emitted light, so that minor
Exploded schematic shows line drawings of five layers inside the optofluidic flow meter.

Optofluidic Flow Meter

NIST Inventors
Zeeshan Ahmed and Gregory A Cooksey
An optofluidic flow meter to determine a rate of fluid flow in a flow member includes: the flow member; a primary fluid conduit disposed in the flow member and that receives a fluid; a secondary fluid conduit disposed in the flow member; and a fiber optic comprising a fiber Bragg grating interposed
Created September 24, 2019, Updated December 8, 2022