Protein and salt: Spatiotemporal dynamics of events in a drying drop

Self-organization processes in biological fluids and aqueous solutions containing protein and salt in various ratios have been studied in drops drying on the surface of a solid substrate. Morphological and histochemical data show that the salt solution exhibits the phase transition in an organic jelly matrix formed in the system. The physical properties of this matrix influence the kinetics of salt crystallization and the morphological features of the observed salt patterns. Controlled UV-radiation-induced protein damage in protein-salt solutions violates the formation of a regular gel and introduces chaotic features into the salt pattern. A new method of investigation of the self-organization processes in drying drops is developed based on acoustomechanical impedance measurements. It is suggested that the dynamic parameters of salt crystallization in drying drops bear information on the composition of the whole biological fluid.