# "Effects of Acoustic Waves on Microtubules and Cells" by Jack Tuszynski Source: https://www.youtube.com/watch?v=lGfEBo7p3g4 Recap page: https://rapidrecap.app/video/lGfEBo7p3g4 Generated: 2026-03-13T04:03:07.339+00:00 --- ## Quick Overview Acoustic waves, specifically ultrasound, interact with the mechanical structures within cells, like microtubules, causing observable effects such as arresting cancer cells in mitosis when applied at resonant or specific frequencies, although high frequencies, up to 500 MHz in theoretical models, are needed for complete microtubule destruction. **Key Points:** - Ultrasound frequencies used in medical applications typically range from 75 kHz to 3.3 MHz, interacting with cellular mechanics through thermal and non-thermal effects. - The speaker noted that early experiments demonstrated ultrasound could arrest cancer cells in mitosis and cited a 2005 paper showing clinical utility in pancreatic cancer patients. - Microtubules are the most rigid structures in the cell, acting as compression-resistant components, while actin filaments are tension-resistant, forming a system described by Tensegrity theory. - Theoretical modeling showed that for a single microtubule, harmonics N=67 and higher would be underdamped, while lower harmonics would be overdamped, with the first underdamped case estimated at 500 MHz. - Experimental exposure of stabilized microtubules (tubulin in buffer) to ultrasound up to 2 MHz for 1-2 hours caused them to break up and disassemble. - Later experiments using Fibonacci sequences of pulses on yeast, Ha (algae), and Chlorella (green algae) showed differential cell viability based on frequency, with the lowest viability for Ha occurring at 127 Hz. - The speaker emphasized that the mechanical response of cytoskeletal structures is frequency-dependent; rapid stimulation may result in underdamped oscillation before energy dissipates into the viscous solution. **Context:** Jack Tuszynski discusses the mechanical aspects of living cells, focusing on how acoustic waves, particularly ultrasound, affect internal structures like microtubules. The presentation begins with basic concepts of mechanical resonance, the structural stability of cells under Tensegrity theory, and delves into specific mechanics of microtubules, illustrated by experiments involving ultrasound exposure on both isolated microtubules and synchronized cancer cells (HeLa and BO cells). ## Detailed Analysis The lecture explores the mechanical interaction between acoustic waves and cellular structures, starting with the physics of resonance, exemplified by the Tacoma bridge collapse, and applying it to cells containing various structures with different natural frequencies. Tuszynski explains that while many consider cellular systems to be overdamped, resonant interactions are possible depending on the time scale of stimulation; rapid, high-frequency input may not allow enough time for viscous energy dissipation. The cytoskeleton components—microtubules (compression-resistant) and actin filaments (tension-resistant)—are central to cell mechanics, as described by Tensegrity theory, which involves interconnected, pre-stressed elements. Experiments from over a decade ago showed that exposing microtubules stabilized by taxol in buffer to ultrasound up to 2 MHz caused them to break and disassemble after 1-2 hours; similarly, ultrasound exposure arrested synchronized HeLa and BO cancer cells in mitosis, causing microtubule distortion and DNA diffusion. Computational modeling confirmed that for a microtubule modeled as a flexible rod, underdamped resonance conditions require frequencies of 500 MHz or higher, far exceeding the 2 MHz used experimentally, suggesting the observed effects might not be purely resonant disruption. More recent work, conducted by Ed Reedman, involved applying signals based on Fibonacci sequences to cell lines (yeast, Ha, Chlorella), revealing differential cell viability impacts correlated with specific frequencies, such as 127 Hz for Ha algae. ### Ultrasound Mechanics and Cellular Effects - Ultrasound frequencies typically range from 75 kHz to 3.3 MHz, causing thermal and non-thermal effects, including resonant interactions with subcellular structures - Thermal effects always accompany non-thermal effects like tissue reorganization. ### Cytoskeletal Mechanics and Tensegrity - The cell structure involves tension and compression, with microtubules being the most rigid and compression-resistant, while actin filaments resist tension - Experimental observation shows disrupting actin leads to exposed DNA, while disrupting microtubules leads to DNA sequestration. ### Resonance Physics and Overdamping - Resonance occurs when external frequency matches the natural frequency, dependent on the quality factor (Q); high Q means a sharper peak and less friction/viscosity - Cellular systems are often considered overdamped, but rapid stimulation (high frequency) can prevent energy dissipation, leading to underdamped behavior. ### Experimental Findings on Microtubules and Cancer Cells - Ultrasound exposure (up to 2 MHz, 13 microjoules) broke apart microtubules stabilized in buffer solution after 1-2 hours - Exposure arrested synchronized HeLa and BO cancer cells in mitosis, causing microtubule distortion and DNA diffusion. ### Theoretical Modeling of Microtubule Response - Modeling the microtubule as a flexible rod showed that harmonics N=67 and higher would be underdamped, requiring frequencies around 500 MHz for the first underdamped case, far above experimental levels (2 MHz). ### Fibonacci Sequence Signal Experiments - Ed Reedman applied Fibonacci sequence signals to yeast, Ha, and Chlorella, finding differential cell viability responses linked to frequency, with 127 Hz being highly effective against Ha cells. ### Future Directions and Therapeutic Potential - Focused ultrasound could sharpen the tool for targeting tumors, and combining acoustic stimulation with pharmacological agents that arrest cells in G2M phase presents a promising avenue for combination therapy.