Adaptive Focused Acoustics® (AFA®) Technology

In discovery, sample preparation of biological specimens for advanced analytical and diagnostic testing is complex; and poorly controlled. Often the precision of a sample prep process is perceived as the benchmark of a good protocol --- it is independent of the sample. Unfortunately, the accuracy (i.e., the true biological status of a sample) is unknown --- discovery, by definition, does not have internal reference standards.

Covaris designed and engineered a patented acoustic-based technology platform dedicated to rapid, reproducible, and high-recovery pre-analytical sample preparation. The Covaris Adaptive Focused Acoustics (AFA) technology platform, which delivers AFA-energetics, addresses the bottleneck between initial sample collection and downstream analysis across a variety of sample types.

Sample processing with AFA ultrasonic energy is accomplished by precisely controlling the creation and collapse of millions of cavitation bubbles within the closed sample vessel. The AFA electronics uniquely enables focused bursts of ultrasonic acoustic energy. These acoustic processes are performed in an isothermal, non-contact environment – the water bath maintains sample temperature, and only convergent acoustic energy enters the sample vessel.

The ultra-high frequency electronics and transducer produce a wavelength of only a few millimeters which enables the ultrasonic acoustic energy to converge into a focal zone within a sample vessel immersed in the water bath.

The acoustic energy passing through the water bath causes localized pressure fluctuations which form the cavitation bubbles. The AFA generated cavitation bubbles oscillate or grow to a critical size and then collapse which creates hydrodynamic shear stress in the sample. The oscillation and collapse of the cavitation bubbles also generates acoustic microstreaming, which generates bulk fluid flow in the sample.

Watch AFA-energetics in action

The tuning of peak incident power, duration, and duty factor control microstreaming and/or the generation of hydrodynamic shearing forces.

The Covaris Focused-ultrasonicator systems have multiple transducer configurations that enable single-sample or parallel processing of multiple samples in the acoustic focal zone.

AFA technology delivers high frequency ultrasonic acoustic energy in the same acoustic range as medical applications like diagnostic imaging and ultrasound.

• AFA technology has a short acoustic wavelength – Short acoustic wavelengths enable a tight focus of acoustic energy delivery.
• AFA technology is focused – Acoustic energy converges onto a focal zone, improving the efficiency of energy delivery to the sample. Less overall heat is delivered to the sample.
• AFA technology enables temperature control – Focused energy delivery within the sample enables tight temperature control as the process disrupts thermal boundary layers inside of vessels.

The technologically advanced AFA is often confused with more general sonication technologies because both utilize acoustic energy. Probe and Bath Sonication is a simpler technology using low frequency and unfocused acoustic energy.

Ordinary probe and bath sonicators operate at a frequency of 10 to 30 kHz, which is on the edge of the audible (sonic) range. At this frequency, the wavelength is approximately 100 mm which is larger than a typical sample vessel (~10 to 100 mm) and is unable to be controlled and focused into a sample vessel. It is also why sonicators are loud!

In addition, the unfocused acoustic energy of sonicators does NOT dissipate rapidly as the sample, the vessel and the water bath acoustic couplant are all contained in the pressure field; there is minimal thermal differential which would drive heat away from the sample. The result is the sonicator process is converted to heat energy which slowly dissipates… this is particularly deleterious for labile, heat-sensitive biomolecules. The unfocused, dispersed low frequency acoustic energy results in decreased efficiency, and therefore requires much larger amounts of acoustic energy to yield a cavitation event. Heat generated from the excess energy affects the sample, resulting in thermal molecular damage and non-uniform sample processing. In addition, probe sonicators also directly contact the sample, introducing the risk of contamination.

AFA is more reproducible because the acoustic energy is delivered in a non-contact, highly focused manner more closely scaled to the vessel size eliminating the risk of damage from heat or contamination. AFA enables higher quality, higher recovery, rapid sample preparations.