Acoustic properties of metal oxides aqueous suspensions

The feasibility of using aqueous suspensions of several metal oxide nanoparticles as contrast agents for ultrasonic cardiovascular visualization has been investigated. Nanopowders of Al, Fe, and Zr oxides were prepared by the electrical explosion of metallic wires, and characteristics such as particle size, specific area, and particle size distribution, were obtained, as were TEM photographs. Dynamic light-scattering data demonstrated that the aggregation of nanoparticles took place in their aqueous suspensions in the function of mean particle size. Acoustic properties of stable suspensions of nanopowders were studied in an experimental model of circulation with simultaneous measurements performed by a commercially available standard ultrasonic apparatus used in medical institutions. The results indicate that the intensity of the reflected echo signal depends on the chemical nature of the metal oxide and the structure of nanoparticles and aggregates that are formed in an aqueous medium. The presented data show the high ultrasonic echo activity of several metal oxides and, at the same time, form a scientific background for a better understanding of the interactions between nanoparticles and the ultrasonic wave.