Photoacoustic visualization of diatom algae

  • Cvjetinovic J. 1
  • Salimon A.I. 2
  • Novoselova M.V. 1
  • Sapozhnikov P.V. 3
  • Kalinina O.Yu. 4
  • Korsunsky A.M. 2, 5
  • Gorin D.A. 1
  • 1 Center for Photonics and Quantum Materials, Skolkovo Institute of Science and Technology, 3 Nobelya Str., Moscow, 121205, Russia
    2 Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, 3 Nobelya Str., Moscow, 121205, Russia
    3 Shirshov Institute of Oceanology of Russian Academy of Sciences, 36 Nakhimovsky Prospekt, Moscow, 117997, Russia
    4 Faculty of Geography, Lomonosov Moscow State University, 1 Leninskiye Gory, Moscow, 119991, Russia
    5 Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, United Kingdom
Keywords: Diatoms, algae, cyanobacteria, photoacoustic imaging, photoacoustics

Abstract

Photoacoustic imaging is a rapidly maturing imaging modality in biological research and medicine. Its underlying principle is the photoacoustic effect. This method can also be used to study algae containing light-absorbing chromophores, which produce a photoacoustic signal under laser irradiation. Here, we demonstrate successful photoacoustic visualization of unicellular diatom algae called Karayevia amoena. These hierarchical micro/nano-structured organisms mixed with an agarose gel were excited by nanosecond pulsed green, 532 nm laser using a raster scanning optoacoustic mesoscopy (RSOM) approach. We observed a strong photoacoustic signal from diatom cells and showed that it decreases with decreasing diatom concentration. The signal originates from chlorophyll a and c and fucoxanthin. We also studied cyanobacteria to prove that the photoacoustic technique can be useful for visualizing this type of object as well. Photoacoustic imaging is a promising method for remote control of algae cultivation in bioreactors and their natural environment.
Published
2020-09-07
Section
Articles