Relaxation dynamics in crab hemolymph protein: A biophysical approach through dielectric spectroscopy

Physical properties of biological systems are very complex and often difficult to tune with biological properties. Here we report the physical properties of fresh water crab hemolymph; a fluid analogues to the blood in vertebrates. This may be the first ever attempt in case of crab hemolymph to study dielectric properties such as permittivity (epsilon') dielectric loss (epsilon"), static dielectric constant (epsilon(0)) and relaxation time (tau) in order to know the structural properties of hemolymph in the surrounding of water molecules. Time domain reflectometry (TDR) in the frequency region of 10 MHz-30 GHz has been used for this purpose for two concentrations at room temperature. Havriliak Negami equation is used to obtained complex permittivity spectra. The data obtained using TDR was fitted in two-Debye model. Hemolymph in water surrounding shows two relaxations modes. The low frequency relaxation (beta-relaxation) observed around 90 MHz often attributed to the rotation of polar protein molecules in hemolymph and high frequency relaxation (gamma-relaxation) observed around 18-20 GHz corresponds to the rotation of pure water molecules. It has been observed that the static dielectric constants as well as both low and high frequency relaxation times are little concentration dependent.