Bio-heat and bio-mass transport. Cell and tissue mechanics. Nano-acoustics medicine: ultrasound and opto-acoustics in medicine and biology as determined by intracellular, intra-membrane cavitation and bubble dynamics. Acoustic neuromodulation. Biomechanics of trauma and decompression. Acoustics of the inner ear.
Eitan’s new theory combines the physics of bubble dynamics with cell biomechanics to propose a new way of explaining the interaction of living cells and ultrasound energy that was never explained before. This interaction is interpreted as being based on the manner by which the pulsating pressure of an ultrasound exposure separates the two phospholipid leaflets of the bilayer membrane, thereby inducing cyclic expansion and contraction of the intramembrane space within the membrane. This approach is supported by comprehensive physical modeling and simulation results, as well as by compelling in vivo experimental observations where the two leaflets of the membrane are observed separating even by low intensity ultrasound.
Eitan’s main research effort in the last 15 years was to find such a mechanism. In the last years he collaborated with Prof. Shy Shoham applying ultrasound to neuron cells and excitable tissue which attracted Eitan’s mind to the role of the bilayer membrane. He believes that this finding will have major implications on future research of ultrasound induced bioeffects, where until recently, investigations were almost exclusively empirical. Understanding these interactions using the presented concepts could eventually lead to controlled manipulation of cells, tissues and organs by therapeutic ultrasound. Applications such as the induction of angiogenesis, neuron stimulation and pain suppression, permeabilizing the blood brain barrier (BBB) for drug delivery, blocking blood flow to tumors and guiding stem-cell differentiation, could soon be fully understood and controlled. But not only therapeutic ultrasound bioeffects are explained and diagnostic ultrasound could be better assessed; also soldiers in combat and commuters in car accidents – all can benefit from the fact that the sonophore respond to any, large enough negative pressures that can cause rupture of the membranes- what is relevant to the effect of impact on brain, lungs, liver and spleen – in all soft tissue that are damaged by large impact or explosion. And finally not only humans can benefit from the findings and safety criterions can be identified for levels of exposure to sonar of whales and dolphins. It has been long speculated that military sonar – high power source of acoustic waves – can be harmful to marine mammals
Department of Biomedical Engineering.
Technion I.I.T. Technion City
Haifa 32000, ISRAEL