In Thai regenerative medicine, as elsewhere, flow cytometry is used to measure the size, internal complexity and fluorescent markers of thousands of individual cells per second as they pass one by one through a laser beam. A related technique, imaging flow cytometry, also captures a picture of each cell. The flow cytometry data file provides our cell biologists the specifications needed to understand cell population strength before stem cell treatments begin.
Basics of Flow Cytometry – VIDEO
Our stem cell bank in Bangkok uses laser guided Flow cytometers to analyze cell populations such as CD34+ hematopoietic stem cells that are in suspension. Flow cytometry machines measure characteristics of stem cells as they pass one at a time through a narrow fluid stream (the sheath stream) while in suspension. [1]
For proper analysis, flow cytometry requires cells to be in a single-cell suspension, usually in a buffered salt solution, although cells are often grown in culture growth medium before they are prepared.
Some clinical applications for flow cytometry at the cell regeneration center of Thailand extend far beyond traditional counting of lymphocyte immunophenotyping. We also use flow cytometers in cell cloning, to analyze microparticles in PRP platelet plasma, and to characterize adult stem cells, including cord blood derived and placenta derived cells. Flow cytometry is also widely used in research on embryonic stem cells. [2]
A modern flow cytometer consists of 3 systems: optics,fluids and the electronics.
- The optic system is made of lasers that illuminate cells or particles in the stream and optical filters that direct the light signals to the appropriate detectors.
- The Fluid system helps transport the actual particles in the visible stream to the laser beam to be detected i.e using markers.
- The last and most important piece is the electronics system that converts the light signals into binary electronic signals for computers to understand [3]
Modern flow cytometry allows for special laser instruments to identify and sort cells based on their markers. The same system can also sort cells: the stream is broken into tiny droplets, and droplets containing selected cells are given an electric charge so they can be deflected into separate collection tubes.[4]
Published Clinical Citations
[1] ^ E A M Eldebaky, H M E Afifi, S A Pessar, A M S Ahmed, Implication of Flow Cytometry-Based Maturity Score in Risk Stratification of Acute Myeloid Leukemia in Adult Egyptians, QJM: An International Journal of Medicine, Volume 113, Issue Supplement_1, March 2020, hcaa044.006, https://doi.org/10.1093/qjmed/hcaa044.006
[2] ^ S. Elias, O. Almogi-Hazan, M. Aker, A. Ben-Yehuda, A. Bayya, Y. Tal, A diagnostic challenge: PCP in a non-HIV patient, QJM: An International Journal of Medicine, Volume 104, Issue 10, October 2011, Pages 889–891, https://doi.org/10.1093/qjmed/hcq208
[3] ^ R M Said, H M Abdelbary, A M Elaffifi, R A El-Gamal, K A Almuawi, Flow cytometric assessment of CD30 expression in adult patients with acute leukemia, QJM: An International Journal of Medicine, Volume 111, Issue suppl_1, December 2018, hcy200.092, https://doi.org/10.1093/qjmed/hcy200.092
[4] ^ A.C. Phillips, D. Carroll, C.R. Gale, M. Drayson, G.D. Batty, Lymphocyte cell counts in middle age are positively associated with subsequent all-cause and cardiovascular mortality, QJM: An International Journal of Medicine, Volume 104, Issue 4, April 2011, Pages 319–324, https://doi.org/10.1093/qjmed/hcq199
