Absorption of ultrasound in biomolecular solutions

Experimental results on the absorption of ultrasound in solutions of biomacromolecules are presented. Absorptions of albumin in four buffers indicate that their presence affects absorption supporting a solvation mechanism. Proline, bacitracin, hemoglobin, and three synthetic phosphatidyl choline lipids all have increased absorptions in organic solvents. Absorptions for protein mixtures at pHs where one molecule has negative net charge and the other positive do not indicate a relevant role for electrostatic interactions in absorption. Glutaraldehyde polymerization of an albumin solution caused no change in absorption. Lipid absorption measurements support interaction observations with proteins. From these results it is concluded that molecular size, structure, solvation, and solute interactions are relevant factors in the absorption of ultrasound in biological material