Raman`s Narrower Fingerprint Set to Broaden Utility of Flow Cytometry

Andor Technology Plc has announced that researchers have successfully tested the first proof-of-concept of a Raman Spectral Flow Cytometer (SFC), thanks to its unique Electron Multiplying CCD (EMCCD)
camera NewtonEM. Raman Spectral Flow Cytometry promises to revolutionise cell characterisation by allowing hundreds of variables to be observed simultaneously. It will also make it far easier to distinguish
between different cell types given the narrow spectral fingerprint compared to fluorescence. The group hopes this new technique will eventually complement traditional flow cytometry, which can only currently
characterise cells using a maximum of 19 parameters, with traditional side scatter and different fluorescent colours techniques.

The researchers from Los Alamos National Laboratory successfully developed their new design of high-resolution flow cytometer by incorporating a highly sensitive EMCCD camera from Andor. Previous spectral
flow cytometer designs had used single point detectors such as photomultipliers, restricting instantaneous spectral information. Raman spectra have narrower wavelength bands than fluorescent labels meaning
hundreds of separate variables can be measured without overlap between wavelengths. Fluorescent labels attached to cells in traditional flow cytometry emit over a wide range of wavelengths, so there is a
limit to the number that can be used.

The Raman signal in the group’s Surface Enhanced Raman Spectroscopy (SERS) technique is boosted by binding metal nanoparticles to the cells. The SERS emissions are measured using Andor’s top-of-therange
NewtonEM camera, the only EMCCD spectroscopic detector on the market. It boasts single photon sensitivity high spectral rate and up to 95% QE.
In time, it is hoped that Raman spectral information could also be used to complement and improve the ability of flow cytometers to sort cells as well as identify different cells.