The propagation of optical radiation and thermal field in cell culture media
To conduct research on cell cultures, special water mediums are required to support their vital activity. These mediums called buffers or cell culture media when storage and growth are considered respectively. Knowledge about the interaction between light and various cultivated organisms is important for diagnostic and therapeutic purposes. Recent studies show that the optical generation of singlet oxygen forms can modulate physiological cellular processes and oxidative stress. However, the issues of methodological support of this approach remain relevant. The purpose of this work was to study the optical properties of cell buffers and cell culture medias and to develop models based on them for describing the propagation of light and the thermal field in the medium.
The optical properties of a set of solutions commonly used as buffers and cell culture media were investigated. The optical transmission range and scattering properties of HBSS and cell culture media buffers based on DMEM, FBS, and Pen-Strep solution with different concentrations of cell culture of melanoma B16 and hepatocellular carcinoma H33 (0.5E5; 1.5E5; 2.5E5; 3.5E5; 4.5E5 cells/mL) were determined. A gelatin solution was used to ensure a uniform distribution of cells in the test sample and to exclude cell subsidence.
Using the Shimadzu UV 2600 spectrophotometric complex (Shimadzu, Japan), successive measurements of the transmission coefficient (T, %) and the diffuse reflection coefficient (Rd, %) of the studied samples were made in the spectral range of 220-1400 nm with a step of 0.5 nm. The absorption coefficient and the reduced scattering coefficient were calculated using the inverse adding-doubling method.
Using the numerical Monte Carlo method, maps of the fluence rate (radiation power distribution) over the solutions volume and the corresponding radiation attenuation over the depth were obtained. The temperature distribution was calculated using the COMSOL Multiphysics heat transfer module by combining the Beer-Lambert law with the Pennes bioheat transfer equation.
The simulation allows us to predict the optimal parameters of experimental singlet oxygen generation systems in the buffers or cell culture media and to explain the obtained measurement results.
The work was supported by the grant of the President of the Russian Federation for state support of young Russian scientists No. MK-398.2021.4.
Research & Development Center of Biomedical Photonics, Orel State University