4 replies to this topic

[aconita]

The idea is to build an ultrasound device appositely conceived for home made liposomal encapsulation.

 

Usually that is achieved with an ultrasonic cleaner filled up with water and lecithin, some recommend to place a glass container in the ultrasonic bath and to fill that with water and lecithin.

 

The tech guys in the laboratory use a transducer prob in immersion.

 

The ultrasonic cleaner method usually is not very efficient achieving about a 70% encapsulation at best, which is probably good enough but not optimal and the stainless steel tank will leach metal particles in the compound I would prefer to avoid.

 

Placing a glass container in the tank eliminates the contamination issue but decreases the sonification power lowering the encapsulation percentage even further.

 

The immersion transducer prob gives the best amount of power/encapsulation but probably the worst metal contamination, plus the probe bell is kind of tricky to build or expensive to buy.

 

Thinking about a glass container such a beaker of about 500ml capacity and epoxy glue a 28KHZ/50W transducer to the bottom of it, this should make a quite powerful sonificator, well superior to an ultrasonic jewelery cleaner, leaching little or almost no contaminants (hopefully).

 

The question is: would the glass perform as intended, will it break or not resonate how it should? 

 

Yes,I know, I can just try and see by myself...

 

The point is if it is not going to work the transducer may get damaged and it may not be fun if I have to un-glue it...therefore if somebody has technical expertise in this field and is willing to save me money and time I will really much appreciate.

 

Thanks!   

[Logic]

Toss one of these in a beaker.

http://www.mainlandm...om/foggers.html

 

[aconita]

Thanks Logic!

 

The power output of these devices seems kind of low and frequencies unknown (which may be relevant to the encapsulation process), probably in a magnitude about 1MHZ or so which is not what we need for liposomal encapsulation (AFAIK 28-40KHZ), we still get the problem of the transducer in direct contact with the liquid too and consequent metal particles pollution, not to mention the rubber of the wire, gaskets, etc...

 

The thing is ultrasounds creates huge forces that erode 316 stainless steel or even high quality titanium, probably glass too will leach some compound but hopefully that would be the less concerning, any other material in contact with the liquid should be of concern as far as contamination, I think.     

[nightlight]

I have used  a thin glass beaker (from a large, 12 cup, French press carafe) to make Liposomal C for over a year. While the glass didn't crack or break or chip, after few weeks it did become foggy then completely opaque in a ~1 inch circle right above the ultrasonic plate.  That seems to be only aesthetic problem and not a functional one.

 

Regarding the power of ultrasound transmission into the beaker, I have experimented with "aluminum foil test" with & without beaker -- you drop a small rectangle of aluminum foil into the water and observe/measure how quickly it dimples and gets shredded by ultrasound. I have found that by keeping the beaker ~1 cm above the metal tub bottom (via plastic ring) yields the best transmission, which is nearly the same as in the test for the bare tub.

[aconita]

Thanks Nightlight!

 

I guess you are talking about a glass beaker in immersion in an ultrasonic cleaner tank...

 

I am aware that in that case for best results the beaker should not be in contact with the tank bottom and a couple of cm from it at least but if the aluminum foil test results indicates 1cm as best I'll take note of that.

 

It is good news that the test indicates very little loss in the beaker because I would have expected more substantial losses according to the theory that any "obstacle" dampen the sound waves, eventually it seems that in this particular case the dampening effect may be negligible and of course it is good news!

 

Glass getting opaque because the glass is loosing particles due to the ultrasound waves, amazing isn't it?

 

Those ultrasound waves develop an incredible huge amount of power...

 

A proper beaker made of borosilicate glass minimizes the migration of sodium ions from the glass matrix and may be better in an ultrasound environment, borosilicate glass is more heat and shock resistant too maybe reducing a little bit the leeching of particles.

 

By the way do you know the frequency, output power and water tank capacity of the ultrasonic cleaner ?

 

I guess the opaque on the glass would feel less smooth at the touch, did you notice if is only on the outside of the beaker or inside as well?