Poster R10 - Two-photon fluorescence flow cytometer with non-diffracting Airy beams

Introduction: Flow cytometry is an optical technology that uses laser light to analyze and count cells or other small particles suspended in a fluid. Clinical and research applications for this technique include disease monitoring, cancer detection, and immunology, with cells often sourced from blood, lymph, or bone marrow. In vivo flow cytometry systems have been developed, but existing systems using one-photon excitation are challenged by light scattering; systems using two-photon excitation, while reducing scattering, are limited by small excitation volume. Non-diffracting beam types such as Airy beams allow theoretically infinite depth of field, which make them excellent candidates for application to scanned-beam flow cytometers.

Materials and

Methods: The system developed uses an SLM to modulate the phase front of a femtosecond pulsed laser beam to produce an Airy beam, which is scanned to produce a light sheet for sample excitation. To model cells traveling within a blood vessel, fluorescent polystyrene microbeads were flowed through a microfluidic channel.

Results, Conclusions, and Discussions: The system was demonstrated to successfully detect two-photon fluorescence from individual beads passing through the Airy light-sheet. The light-sheet was observed to have a non-diffracting distance of over 100 microns, which would enable coverage of veins and arteries of approximately this diameter. With its unique properties of non-diffracting and self-healing this system is an ideal candidate for in vivo applications.

Acknowledgements (Optional): US National Science Foundation (NSF) (1827745)