Sciencemadness Discussion Board

Ultrasonic... HAND cleaner?

GreenD - 15-9-2011 at 13:13

I'm working on a project, and I need to know whether ultrasonic vibrations in a solution can damage skin cells.

i.e. would washing or rinsing your hands off in an ultrasonicator damage you?

I know that people use sonicators to break open cells in liquid media, but ... skin cells?

watson.fawkes - 15-9-2011 at 13:42

Quote: Originally posted by GreenD  
would washing or rinsing your hands off in an ultrasonicator damage you?
That all depends on the amplitudes of the various standing waves. Above some threshold, there's certainly damage. Below some other threshold, there won't be any. I have no idea what these threshold values are.

AndersHoveland - 15-9-2011 at 15:15

Well this certainly is an interesting question, so determined to find out. Borrowing a hamster from a friend (he actually is not aware that the animal was borrowed for experimental purposes, but those devils have been breeding out of control, and he has frequently expressed his intention to get rid of some of them), the test subject was placed into an ultrasonic jewelry cleaner (Brookstone 120W), which was filled only a third full of water. The ultrasonic bombardment was initiated for a period of 10 seconds. The lid was removed and the creature was observed to be extremely panicked. The lid was closed back and the bombardement continued for another 10 seconds. After this time interval, the creature appeared partially stunned and was relatively motionless. The test subject was then returned to its original enclosure. It could not be induced to run on its wheel.

It can therefore be induced that such ultrasonic devices do indeed have a detrimental effect towards living tissue, and caution should probably be excercised.

Ultrasonic cleaning devices in the range of 50-200W generally only result in redness and skin discomfort, although longer exposures cause tissue damage, moderate swelling, and could potentially result in damage to joints. Direct skin contact with the metal transducer causes "burns", likely similar to frost burns. Dipping a finger into the water of a typical (small) activated jewelry cleaner only momentarily will only result in a slightly uncomfortable tingling sensation, however.

In higher powered ultrasonic cleaners, one should not remove any objects from, or hold objects in, the cleaner while it is activated. For unknown reasons, doing this causes a painful sensation to the wrists.

[Edited on 15-9-2011 by AndersHoveland]

DDTea - 15-9-2011 at 17:56

Anders, surely you could have gained more useful data from a cursory literature search. The experiment you performed was designed so poorly and carried out so haphazardly that no meaningful data can be extracted from it. You simply observed the hamster's demeanor after subjecting it to an ultrasonic device, then tried to correlate its demeanor to tissue damage. Without proper histological testing, no conclusions can be drawn as to whether ultrasonic devices have detrimental effects toward living tissue. What was your hypothesis anyway? What peer-reviewed information was it based on? Seriously Anders, what the fuck.

The frequency of the ultrasound is also important when considering possible tissue damage. Higher frequencies have shallower depths of penetration into tissue.

Cason - 15-9-2011 at 19:24

Thank you DDTea. FYI There was a mechanic in my town who stuck his hands in the US cleaner to move parts around.. sometimes holding them until the grease loosened up. After about six months he suddenly had pain whatever he did. Turned out all the bones in his hand were fractured. He had his right hand in a cast for four months and did PT for a year. His boss kept a copy of the X-ray over the US bath for a year afterwards. Not an urban legend.

DougTheMapper - 15-9-2011 at 19:31

Quote: Originally posted by DDTea  
Seriously Anders, what the fuck.


http://www.youtube.com/watch?v=kBtS5R_e-Xo&feature=relat...

Here's a 28kHz model used for cleaning skin. I don't think cavitation damage is an issue here because the volume of the working fluid is so small.

The wrist phenomenon is likely due to cavitation in the wrist joint as the signal telegraphs from bone to bone through the synovial fluid, and, in the case of the hamster, probably the serebrospinal fluid, damaging the brain.

Not to be unscientific or anything, but what advantages do you think ultrasonic cleaning of the hands would have over other methods?

bbartlog - 16-9-2011 at 05:16

There is also some suggestion that the ultrasound used for prenatal fetal visualization is not entirely safe (of course it operates at vastly lower amplitude than a sonicator or cleaner).

GreenD - 19-9-2011 at 16:13

Interesting responses everyone,

the reason I got into this discussion was the removal of endospores from hands.

Alcohol wipes help endospores STICK to your skin, spreading them around. Soap and water is ok for removal, but not ideal - just curious if this was a viable option...

Seems as it may be, but not for powerful cleaners...

Saerynide - 20-9-2011 at 08:03

Quote: Originally posted by Cason  
Thank you DDTea. FYI There was a mechanic in my town who stuck his hands in the US cleaner to move parts around.. sometimes holding them until the grease loosened up. After about six months he suddenly had pain whatever he did. Turned out all the bones in his hand were fractured. He had his right hand in a cast for four months and did PT for a year. His boss kept a copy of the X-ray over the US bath for a year afterwards. Not an urban legend.


Omg im so glad i never stick my hand in the ultrasonic bath. I had a feeling it would break some cells, and I was always worried whatever I was sonicating would explode in my hands (because sometimes they do) I dont even like being around it when its on because the sound drives me crazy.