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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.


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



NIST Inventors
Gregory A Cooksey , Paul Patrone and Anthony J. Kearsley


NIST Inventors
Anthony J. Kearsley , Gregory A Cooksey and Paul Patrone
patent description The invention, which we call multiplexed amplitude modulation fluorometry, is a method of signal generation, acquisition, and analysis that can simultaneously detect and distinguish fluorophores contained on or in many distinct samples separated in space and/or wavelength. The
Exploded schematic shows line drawings of five layers inside the optofluidic flow meter.

Optofluidic Flow Meter

NIST Inventors
Zeeshan Ahmed and Gregory A Cooksey
The NIST optical flow meter uses a photonic sensor to detect pressure changes inside a microfluidic channel, which is then used to calculate volumetric flow rates. It provides on-chip assessment of flow and heat transfer resulting in improvement in fluid metrology and advances in biological sensing.
Created September 24, 2019, Updated December 8, 2022