Chromatin shearing is a key step in the ChIP workflow that can dramatically impact your experimental outcome, but so often the task of chromatin shearing is tackled with just brute force. Sub-optimal sonication or enzymatic approaches are like using a sledgehammer to chop fruits and vegetables. Fortunately, Covaris’ Focused-ultrasonicators use Adaptive Focused Acoustics (AFA) technology to bring a little finesse and elegance to chromatin shearing. Teamed up with their truChIP™ Chromatin Shearing kits, the Covaris AFA platform can boost the quality of chromatin material that heads into ChIP experiments and ultimately, improve your results.
No matter what the ChIP readout, Covaris AFA sets you up for success.
The Sounds of ChIP Success
AFA technology is a cousin of the focused-ultrasound lithotripsy used in clinics to break up kidney stones, only in this case, the high frequency (500kHz) short wavelength (1-2 mm) acoustic energy relieves the pain of shearing chromatin, instead of a urinary blockage. Here are some ways the AFA approach pays off:
- Focused-ultrasonicators apply the acoustic energy to a very small, localized area within the sample tube, where the cavitation and shearing events occur. This means much less time and energy is needed to shear chromatin to the desired size range. Shorter, less intense shearing cycles avoids damage to epitopes in the protein:DNA complexes, increasing the IP efficiency and sensitivity of your ChIP assay.
- It’s isothermal, so samples stay continuously cool. You can skip all the old tricks you use with ordinary bath and probe sonicators to keep samples chilled, like cold water exchange, ice baths, and breaks between treatments.
- Less chromatin fixation time is needed during sample prep. That’s because AFA works fast, doesn’t heat up the sample and uses lower energy than unfocused sonication-based approaches. That gentle touch protects against broken cross-links and doesn’t risk destroying epitopes while shearing chromatin.
truChIPTM and AFA: Reproducibility By Design
Less energy means less heat, and that equals less sample damage. That simple equation is what AFA is all about, so the entire AFA system from truChIP buffers, to the sample tubes is engineered for highly efficient transfer of shearing energy to the sample and to maintain isothermal conditions. Loads of time was spent in the Covaris R&D labs optimizing the buffers, and conditions for the truChIP Chromatin prep kit so that it contains the least possible amount of harsh detergents and delivers guaranteed performance with any mammalian cells. In addition, the AFA sample tubes are engineered with a bottom curvature that matches the geometry of the instrument’s transducer, which maximizes energy transfer to the target. Each part works hand in hand with the others to create a complete chromatin shearing system. That efficient design leads to excellent reproducibility that’s hard to achieve with most of the shearing methods currently available.
Feel the truChIPTM Love
Not feeling so hot about beating up all your previous ChIP samples? Don’t feel bad, because now you can do something about it. Find out all about Focused-ultrasonicators, AFA technology and truChIP Chromatin Shearing products at the Covaris website.