Deep ultraviolet lasers for flow cytometry

Oxxius deep UV lasers for flow cytometry today

Published in Cytometry Part A in 2019, this paper evaluates a deep ultraviolet laser for flow cytometry at 280–300 nm, co-authored by researchers from the NIH and Oxxius, in the context of high-dimensional immune cell analysis. As BUV polymer dyes pushed cytometry toward 30-parameter panels using 355 nm UV excitation, the next frontier required a new excitation wavelength: 280–300 nm, capable of exciting a new generation of deep UV polymer fluorochromes to push simultaneous parameter counts beyond 30.

The Oxxius compact solid-state laser evaluated in this study demonstrated that deep UV excitation at this wavelength is not only feasible in a flow cytometer format, but produces meaningful fluorescence signals from the new deep UV dye series — validating the approach for future high-dimensional cytometry panel development. The compact footprint of the Oxxius source, designed for direct integration into commercial cytometer platforms, was a key factor enabling this evaluation.

Why deep UV excitation matters for immunology

Immune cell analysis by flow cytometry is increasingly constrained by spectral overlap between fluorescent probes when using conventional laser lines (355 nm, 405 nm, 488 nm, 561 nm, 638 nm). Adding a deep UV excitation channel at 280–300 nm opens a new spectral window where autofluorescence is minimal and dedicated polymer dyes can be designed with large Stokes shifts, enabling simultaneous detection of additional parameters without adding spectral complexity to existing panel designs. Oxxius’s LCX-280 and related deep UV sources provide the compact, low-noise deep UV excitation demonstrated in this landmark cytometry study.

Abstract

Modern flow cytometers require multiple laser wavelengths to excite the wide variety of fluorescent probes now available for high‐dimensional analysis. Ultraviolet (UV) lasers (typically solid state 355 nm) have become a critical excitation source for the Brilliant Ultraviolet (BUV) series of polymer fluorochromes. The BUV dyes have pushed the number of fluorescent probes available for simultaneous analysis to nearly 30, allowing an unprecedented level of precision for immune cell analysis. However, immunologists are already seeking analyze more than 30 simultaneous parameters, requiring both new fluorochromes and corresponding laser wavelengths. A group of polymer dyes requiring deep ultraviolet (UV) excitation (~280–300 nm) is currently under development, allowing the expansion of high‐dimensional cytometry beyond the current 30 color limit. In this study, we evaluated a newly available laser …