Selection of hyperosmotic agents for optical clearing of biological tissues in terahertz frequency range

Terahertz (THz) spectroscopy and imaging allow to differentiate between healthy tissues and tumors of different types, due to keen sensitivity to the water content. However, a high absorption of THz waves by water molecules limits application of THz technology for medical diagnosis. Among the existing methods for tissue clearing only immersive optical clearing (IOC) is acceptable for in vivo study. In order to choose optimal agents for IOC, we reconstructed THz dielectric properties of common agents using methods of THz pulsed spectroscopy and we measured diffusion coefficients of agents in rat brain analyzing collimated transmittance in visible range.