Branson Sonifier 450 - (Nov/25/2008 )
Who has used this sonicator for their CHIP? In the protocol that I tried to follow, they used another sonicator with different power setting , and they sonicated at 5 x 15 seconds. Can someone give me some quick pointers about the power settings on this sonicator? I don't want my samples to foam:(
Thanks
Sorry for not replying sonner 
We use a digital Branson 450 sonicator. Each cell line should be tested separately for pulse lenght, but here's my settings :
Cell line : 3T3-L1
Pellet adjusted to 500 µl with IP dilution buffer
Sonic : 3 X 15 sec at amplitude 60, with 3min lapse between each pulse.
Hope this helps!
Does anyone know what amplitude that would be in a diagenode sonicator?
It appears to have three levels low, medium and high and I dont know what kind of amplitude this represents.
Also how many cells do sonicate in 500microliters?
Ive been trying to optimise my sonication but it doesnt work 
We use a digital Branson 450 sonicator. Each cell line should be tested separately for pulse lenght, but here's my settings :
Cell line : 3T3-L1
Pellet adjusted to 500 µl with IP dilution buffer
Sonic : 3 X 15 sec at amplitude 60, with 3min lapse between each pulse.
Hope this helps!
hi, thanks for replying! I'm just wondering what duty cycle do you use? less than 50%? Is that what you mean by pulse length? Also I think the power output goes from 1 to 10. It makes it a lot complicated to have 2 adjustable variables lol.
Pulse lenght is the number of seconds you sonicate (i.e. 15 sec in my example).
The amplitude of the sonicator is set at 60%
As fot the power output.. I have no clue, neither for what you mean by "duty cycle"
The amplitude of the sonicator is set at 60%
As fot the power output.. I have no clue, neither for what you mean by "duty cycle"
I think this is the exact unit that I'll be using. I think I know what you mean by the amplitude setting, (has to be the duty cycle). I dunno what the output control do tho, I'll leave it at default setting then lol.
Btw do you sheer your chromatin to 500 bps?
The amplitude of the sonicator is set at 60%
As fot the power output.. I have no clue, neither for what you mean by "duty cycle"
I think this is the exact unit that I'll be using. I think I know what you mean by the amplitude setting, (has to be the duty cycle). I dunno what the output control do tho, I'll leave it at default setting then lol.
Btw do you sheer your chromatin to 500 bps?
The output control is actually the amplitude control. Duty cycle controls the length of each pulse when the sonicator is not in continuous mode. I would set this to 50-70% (this can be adjusted depending on how much heating you get for each round of sonication) and then just adjust the output control. The only other variable is the number of rounds (10 to 15 pulses each) of sonication you do. To decrease foaming try sonicating in a volume of at least 300ul and keep the tip no more than a millimeter or two away from the bottom of the tube.
My understanding of the duty cycle is that if it is set to 50%, it will sonicate for 0.5 sec, then off for 0.5 sec. If you set it to 80%, then it will sonicate for 0.8 sec, and be off for 0.2 sec.
My experience with output control is that it doesn't make a great deal of difference (with a branson-250). Sometimes I could hold the tip in the sample and you can hear the machine trying to sonicate but no mixing happens and the output barely moves. Yet if the sample is held at the right depth then you will hear the characteristic 'squelch' sound (through your protective eafmuffs of course) and the output as read off the sonicator will register something. Usually about 40 in my experiments.
My advice would be to set duty cycle to no more than 60% - the best tip I ever heard to avoid foaming. Leave the output control constant, at whatever setting you choose. Play with the amount of cycles you hit your samples with to get the best results.
Good luck!