Variation of optical properties of mouse brain using an optical clearing agent: experimental and simulation approaches

For optical diagnosis and therapy in medicine, tracking changes in tissue refractive index (RI), absorption, and scattering coefficient is important. These characteristics may be measured using a variety of techniques. Examples of simulation and experimentation techniques for determining optical parameters are inverse Monte Carlo (IMC) simulation, integrating sphere spectroscopy (ISS), and diffuse reflectance spectroscopy (DRS). The depth of optical measurements is limited by tissue light attenuation in all methods. Using optical clearing agents (OCAs) is a common method to increase optical depth and reduce light scattering in biological tissues. Thus, optical measurement techniques employing new (OCAs) can potentially achieve greater efficiency than traditional agents. This study aims to measure the optical properties of an unsliced mouse brain in the visible spectrum using an OCA composition to clear the tissue. The mouse brain model is useful for developing neuroimaging techniques and optical monitoring of brain activity. In this study, DRS, ISS, and IMC are used to analyze the changes in the RI, absorption, and scattering coefficients of the unsliced mouse brain. A fluorescence test was additionally conducted to evaluate the efficacy of the introduced OCA in comparison to glycerol. The findings and OCA described in this study may be beneficial in optical neurostimulation and brain disease treatments.