LILI WANG, NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY
Flow cytometry is an incredibly powerful technique that has been used for decades to measure the physical and chemical characteristics of populations of cells, constituents of cells, and other small particles of biological and nonbiological origin. As the uses of this technology have expanded, so too has the need for standardization in measurement parameters.
An emerging application space for flow cytometry is across the regenerative medicine and advanced therapy fields.
In flow cytometry, particles flow in single file through the detection region, where they are counted as part of a population. Each population can be separated and collected downstream, if desired. The technique has become a critical tool in clinical diagnostics, in the development and testing of advanced therapeutics such as cell and gene therapies and new vaccines, and in cancer research and diagnosis.
Continuous improvements in the technique’s hardware and software, as well as in labeling and dye components, have enabled the detection of increasingly smaller and/or dimmer objects, along with simultaneous measurements of multiple biomarkers, through high-dimensional, multiple-channel cytometry. Similarly, combining flow cytometry with fluorescence in situ hybridization or other imaging modalities provides unique opportunities to gain insights into biological processes such as cell-cell interaction, virus infection of a host cell, and more. However, few measurement standards exist for evaluating the accuracy of results.
The National Institute of Standards and Technology (NIST) has deep expertise in fluorescence measurements and has been supplying high-accuracy measurements to the research community for nearly 20 years. Under the auspices of the NIST Flow Cytometry Quantitation Consortium, the agency has been primarily focusing on providing measurement capabilities and services to calibrate the fluorescence signal using microspheres or beads according to a unit called the equivalent number of reference fluorophores (ERF). This process will make the measurements traceable to the International System of Units (SI).
An emerging application space for flow cytometry is across the regenerative medicine and advanced therapy fields. Advancements in cell and gene therapies are revolutionizing health care by providing curative treatments for previously untreatable diseases. Flow cytometry has been applied to measure a number of quality attributes, or critical quality attributes, for a given cell product. For example, flow cytometry can be used to establish identification by distinguishing various cell populations; to determine the cell count, viability, and potency; and to assess the product purity, free from extraneous materials. However, a major challenge is the lack of reproducibility and comparability of results across various flow cytometry platforms.
NIST has launched the Flow Cytometry Standards Consortium to help develop standards and measurements to support the discovery and manufacture of these groundbreaking therapies.
The NIST-led consortium provides a neutral forum for stakeholders in the biotechnology and health care sectors to identify and address common measurement challenges, exchange ideas, and jointly accelerate the development of standards and reference materials for quantitative flow cytometry. The scientific and research community can benefit from NIST’s expertise in measurement sciences to supply reliable solutions with built-in high accuracy and confidence in measurements. In addition to the agency’s robust flow cytometry capabilities, NIST has built a state-of-the-art measurement infrastructure for deep characterization of cells and their functions using multiomics technologies (genome, transcriptome, proteome, etc.).
The consortium expects to develop measurement solutions, standards, and best practices for flow cytometry that will enable more accurate quantitation and improved reproducibility and comparability of measurement results. These capabilities will ultimately accelerate the translation of modalities in research into new treatments for patients.
The Flow Cytometry Standards Consortium Workshop was coordinated by NIST on Feb. 16-17 for an online, open public discussion of current efforts, needs, gaps, and consortium opportunities. The workshop presentations and a recording can be found at www.nist.gov/news-events/events/2021/02/flow- cytometry-standards-consortium-workshop.
Meet the author
Lili Wang, Ph.D., is a senior research scientist at the Biosystems and Biomaterials Division of NIST. She is a world-leading expert in quantitative flow cytometry, which is a critical technique for diagnostics and advanced therapeutic development. She serves as the technical lead/manager for the NIST Flow Cytometry Standards Consortium — a major public-private partnership with key stakeholders from other agencies, industry, and academia — where she and her team work with consortium members to address pressing measurement and standards needed for bioassays, including SARS-CoV-2 antibody testing for diagnostics, vaccine testing, and surveillance. She obtained her doctorate in chemistry from the University of Notre Dame in 1996 and joined NIST in 1998.
The views expressed in ‘Biopinion’ are solely those of the author and do not necessarily represent those of Photonics Media. To submit a Biopinion, send a few sentences outlining the proposed topic to [email protected]. Accepted submissions will be reviewed and edited for clarity, accuracy, length, and conformity to Photonics Media style.