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1In scattered light of cell proliferation: cell growth and attachment monitoring
M. Naumenko1, A. Moskalensky1*
1-Novosibirsk State University, 1, Pirogova Str., Novosibirsk, 630090, Russia
Studying cell growth, division, and adhesion advances scientific knowledge across a wide range of disciplines, including cancer formation research and anticancer drug development [1]. Despite the existence of a diverse array of techniques and assays (e.g. automatic cell counting, XCelligence electric impedance measurements) the need for development of cost-effective, non-invasive, and easy-to-perform methods for tracing cell proliferation remains high. This work is focused on development and validation of a device that monitors adherent and suspension cell cultures via laser light scattering measurements.
Firstly, we modified the device created in our laboratory before to trace the changes of cells cultured in suspension [2]. Originally, the optical part of the device comprises a 850 nm, 3 mW dot laser module along with the BPW34 photodiodes arranged in a row to align with the width of a standard T25 biological cell flask. In order to enable measurements of adherent cell layer formation we extended the optical scheme of the device with the second laser of 660 nm, 5 mW directed along the bottom of the flask. We validated the device using various cell models, e.g. E.coli bacterial suspension culture and HEK293 adherent cell culture. We determined the dynamic range of the device using serially diluted suspension cell cultures. Also, we implemented complementary assays to verify our method.
Since the adherent cell layer is heterogeneous and consists of cells of different adhesion strength that is correlated with cell potential to metastasize [3], we are performing another modification to use the total internal reflection mode. For this purpose, we use the laser module with the wavelength of 980 nm and special optics to make the radiation 'trapped' in the flask bottom. The interaction of the evanescent wave with adherent cells leads to enhanced intensity of the scattered light.
The reproducibility and accuracy of the measurements was testified with experimental results. Therefore, we developed a novel optical device to control cell proliferation and attachment under the standard biological conditions. The device allows continuous measurements of cell system proliferation and perturbations in a cost-effective non-invasive manner and could be widely applicable in various fields of cell research including the studies of cancer.
The study was supported by the Ministry of Science and Higher Education of the Russian Federation (project FSUS-2020-0039). We would like to thank Petr Laktionov (Laboratory of Epigenetics, NSU) and Sergey Kulemzin (Institute of Molecular and Cellular Biology SB RAS) for providing us with biological samples as well as for their constructive input. We express our gratitude to the entire team at the Laboratory of Optics and Dynamics of Biological Systems for their support.
[1] E. Sazonova, M. Chesnokov, B. Zhivotovsky, et al, Drug toxicity assessment: cell proliferation versus cell death, Cell Death Discov. 8, 417 (2022).
[2] D. Litunenko and A. Moskalensky, Wireless monitoring of cell cultures based on light scattering: a novel optical scheme and portable prototype, J. Biophotonics, 17(1):e202300234 (2024).
[3] E. Vargas-Accarino, C. Herrera-Montávez, Y. Cajal, S. Ramón, T. Aasen, Spontaneous Cell Detachment and Reattachment in Cancer Cell Lines: An In Vitro Model of Metastasis and Malignancy, Int J Mol Sci., 22(9):4929 (2021).
