1. Acoustical Levitation and its Biological Applications 2019-03-14
Jermaine Wegner
Acoustical Levitation and its Biological Applications

2. What is Acoustical Levitation ?
First What is Acoustics? Acoustics as a field of study is primarily interested in studying various types of waves as they oscillate through a specific medium Understanding Sound as a pressure wave allows us to use the pressure of the wave to generate a “force” on an object. A Phenomena that arises when the vibrations of sound waves traveling through air (any fluid really) to match the force of gravity causing an object or material to essentially levitate without support.
Give some examples of Sounds in everyday life. -Speech -Ultrasound machine used to break up kidney stones or destroy tumors
-Ultrasound pregnancy
-feel a sonic boom

3. Have well defined areas of minimum amplitude which are known as nodes,
Standing Waves
::When the boundary of a Wave are fixed, there will be a transmitted wave, as well as a reflected wave. When these two waves interfere with one another They give rise to what is known as a standing wave. They can also be thought of as a wave which oscillates with respect to time, yet has a peak amplitude that does not move in space ::Nodes
Standing Waves
Have well defined areas of minimum amplitude which are known as nodes,
Have well defined areas of maximum amplitude which are known as antinodes

4. How A.L. Works
In our case, the nodes also correspond to an area of minimum pressure, and the antinodes will correspond with an area of maximum pressure. What would happen if we oriented a transducer and a reflector at the right distance to produce a standing wave, parallel to the direction of gravity ?
! ::When the boundary of a Wave are xfixed, there will be a transmitted wave, as well as a reflected wave. When these two waves interfere with one another Thuey give rise to what is known as a standing wave. They can also be thought of as a wave which oscillates with respect to timxe, yet has a peak amplitude that does not move in space u ::Nodes It is well known that objects, all things being equal, will move from ;an area of high pressure to low pressure. :: well that’s essentially what is the core of acoustical levatiation . ;
Varying the shape of the transducervoltage waveform had a significant effect on layer thickneuss, with a square waveform creatingu thinner, more distinct lauyers than a sine waveform due to steeper pressure gradients at the nodes. 
Acoustic levitation is a phenomenxon whereby pressuure differexnces of statixonary sound waves can be used to suspend sxmall objects in gases or fluids such as air or water
 !!The cells are thexn in a more naturaxl xform and environment, and the interferxence from the floor of the Petri dish is no longer a hindrance.x

5. An interesting autobiographical note: I don’t know about anyone else, as for me, I notoriously had a difficult time visualizing standing waves.

7. Biological Applications?
The Most Obvious application is hearing, even when you can’t hear it, says the cat to the mouse.
Biological Applications?
::When the boundary of a Wave are fixed, there will be a transmitted wave, as well as a reflected wave. When these two waves interfere with one another They give rise to what is known as a standing wave. They can also be thought of as a wave which oscillates with respect to time, yet has a peak amplitude that does not move in space ::Nodes

8. Cellular Level
-Groups of red blood cells have been observed in ultrasonic standing waves[1],[2],[3]
-Cultures of Cells as well as other Cytoskelatal cultures can be placed in a fluid that replicates a humans blood stream [5]
- We known cancer cells respond differently to ultrasound due to their different densities, than do normal cells. [7]
Cytoskeleton: essentially a tissue that connects a complex network of linking protein filaments, it brings to mind the image what most of us are familiar with.
Cultures of Cells obviously extracted from the subject. Then the user sends a low-frequency sound wave through the fluid, at the respective acoustical levitation frequency(250 kHz, and once the cells are levitated into a stable position ,another ultrasonic wave can be emitted, and essentially an “ultrasound” can be taken , well you may ask, well jermaine, how is this important. Well it would allow us to study the cells in an environment more similar to one in vivo (one that would take place within the organism ) , also different densities react to ultrasound differently, what group of cells Ultrasonic signals from these cultures can be problematic due to the interference of reflections from the culture-plate well. The cell structure is also often deformed from its native state due to adhesion to the culture plate.

9. Human embryonic kidney cells (HEK)
Cellular Level
Groups of cancer cells at 5X magnification . On the left the ultrasound was continuous on the right it was pulsed. [7]

10. Achieving diameters between 9 -15 microns
Cellular Level
(a) Cancer Cells movement towards an aggregation of cancer cells (b) Beginnings of intercellular interactions ( C ) cell aggregation . [7]

11. What’s Next ?
::When the boundary of a Wave are fixed, there will be a transmitted wave, as well as a reflected wave. When these two waves interfere with one another They give rise to what is known as a standing wave. They can also be thought of as a wave which oscillates with respect to time, yet has a peak amplitude that does not move in space ::Nodes

12. How about Levitating an entire animal !
(a & b) Ant (c & d) Lady bugs
(e &f ) Small fish Note: the rule is in cm. [8]
After the acoustic levitator is adjusted to a proper state,
we utilize a tweezer carefully to introduce the animals into
the levitation position. Figure 1 shows the levitation process
of an ant, a ladybug, and a young fish in air. Since the longitudinal
component of the acoustic radiation force Fz is
much larger than the lateral components Fr, these animals
are usually levitated with the largest cross section of their
bodies perpendicular to the reflector-emitter axis, so as to
stabilize their posture. The ant is usually levitated with a
posture as if it is “crawling” in the air Fig. 1a. Sometimes,
it struggled to escape from the constraint of acoustic
radiation force by rapidly flexing its legs Fig. 1b. However,
it failed because its legs can obtain little counterforce
from the air. The posture of the levitated ladybug is similar to
that when it stands or crawls on the ground Fig. 1c. We
can also place the ladybug into the levitation position with its
back downward and belly upward. In this case, the ladybug
can hardly turn its body over by itself. Like the ant, the
ladybug attempted to escape from the levitation force too. It
spread its wings and tried to “fly” away Fig. 1d. Unfortunately,
this attempt failed, too, because the acoustic radiation
force is too strong to break away from, or its wings
cannot function so well as in the static air. During the levitation
of fish and tadpole, water is added to the levitation
region every 1 min by a syringe. Nevertheless, only a very
thin layer of water can be reserved surrounding the young
fish and tadpole because of the limitation of object size. The
young fish is usually levitated in a posture of “side lying”
Fig. 1e. It also failed to escape from the ultrasonic field
with an action of “swimming” by swinging its tail Fig. 1f.
After a continuous levitation of more than 30 min, we
return the animals to their normal living environment. The
ant and the ladybug are still with sufficient vitality, and they

13. Sound Pressure Field distribution
(a) Before the levitation of ladybug and (b) during the levitation of ladybug. [8]

14. Other crystalline structures
(a)The Single NaCl Crystal from levitation, (b) the control crystallization (b) Both were measured after 1.5 h

15. Other crystalline structures
(a) NH4Cl crystallization with the use of acoustical levitation vs (b) the vessel wall control group; both are after a period of 20 min.

16. Other crystalline structures
HEWL crystalline structures using the ultrasonic levitation system after 1hour vs (b) the control group after an hour and a half.

17. Other crystalline structures
(a) Proteinase K crystallization from ultrasonic levitation after 50 min. (b) the control group on the vessel wall after and 1.5 hour.

18. References
[1] [M. Dyson et al., Ultrasound in Medicine 1, 133 (1974)] [2] IN. Baker, Nature, Lond. 239, 398 (1972)].
[3] Acoustic levitation of red blood cells , Robert E. Apfel The Journal of the Acoustical Society of America 62, S55 (1977) [4] Lung cilia# , Howard, Louisa ; Binder, Michael Gif Images: Wolfgang Christian and Francisco Esquembre author of Easy Java Simulation

19. References cont’d
[5] Acoustic levitation device for probing biological cells with high-frequency ultrasound, Patchett, Brian D. The Journal of the Acoustical Society of America 138, (2015)
[6] Harmonic modulation of acoustic standing wave fields for tissue engineering, Timothy Doyle, The Journal of the Acoustical Society of America 139, (2016)
[7] Manipulation of biomimetic objects in acoustic levitation, Castro Angelica, Université Pierre et Marie Curie - Paris VI, 2013
[8] Acoustic method for levitation of small living animals, Xie W.J. Appl. Phys. Lett. 89, (2006)
Physicists at the Argonne National Laboratory are using sound waves to levitate individual droplets of solution containing pharmaceuticals to improve drug development. Drugs fall into 2 categories: Amorphous and crystalline. Amorphous drugs are more efficiently absorbed by the body than their crystalline cousins due to their higher solubility which implies that a lower dose can be used. When solution are evaporated in a vessel, they are much more likely to solidify in a crystalline form. Thus to prevent this from happening, the solution need to be evaporated without touching any surfaces. This is where Acoustic levitation comes in. Acoustic levitation is used to evaporate solutions without allowing them to crystallize.

20. References for the other crystalline structures section
[1](Naoyuki, K., Masaki, M., Takayuki, S., Miho, H., Iwao, M., Satoshi, A., Kazuo, W., and Mitsuhiro, M. (2001)
[2].“Glass spheres produced by magnetic levitation method,” J. Non-Cryst. Solids293–295, 624–629.
[3]. Santesson, S., Cedergren-Zeppezauer, E. S., Johansson, T., Laurell, T., Nilsson, J., and Nilsson, S. (2003). “Screening of nucleation conditions using levitated drops for protein crystallization,” Anal. Chem.75, 1733–1740>> 3 >
[4](Cao, Hui-Ling, (2012)“Rapid Crystallization from acoustically levitated droplets”, J. Acoustical Society of America )
[5](Wolf, S. E., Leiterer, J., Kappl, M., Emmerling, F., and Tremel, W. (2008). “Early homogenous amorphous precursor stages of calcium carbonate and subsequent crystal growth in levitated droplets,” J. Am. Chem. Soc.130, 12342–12347.)[6]D. Foresti, M. Nabavi, M. Klingauf, A. Ferrari, and D. Poulikakos, Proc. Natl. Acad. Sci. U. S. A.110, (2013).
[7]S. Zhao and J. Wallaschek, Arch. Appl. Mech.81, 123 (2011).
this is more of a bonus feature than the actual presentation, but I don’t want to not give credit.