Shearing Samples Simplifies Lots of Preparations
Instead of chopping up samples with mechanical blades, more or less like a food processor, an ultrasonic liquid processor uses a piezoelectric transducer to convert electrical energy to mechanical vibrations that a probe amplifies into pressure waves in the sample. This process creates cavities—bubbles—in the sample, and then cavitation—the bubbles imploding—shears the sample. This seemingly violent process can be controlled to process samples of various sorts.
At Virginia Commonwealth University in Richmond, Ram B. Gupta, associate dean for research and an engineering professor, says, “I use the processor for reactions that contain both solids and liquids.” He adds, “The intense mixing that comes out of physical movement and cavitation greatly increases the reaction rate.”
Smashing the small
“Dispersing and deagglomerating nanomaterials has become one of our largest applications,” says Marc Lustig, director of business development at Qsonica in Newtown, Connecticut. “Ultrasonics is highly effective for breaking the bonds that cause nanoparticles to aggregate.” As nanoparticles get used more—from biology and medicine to industrial and consumer goods—the use of ultrasonic liquid processors will continue to grow.
For a biological example, says Lustig, “We recently introduced a new system for DNA shearing.” Qsonica’s Q800R2 can shear DNA for next-generation sequencing applications. Plus, it can simultaneously prepare multiple samples. As Lustig explains, “We are able to focus highintensity ultrasonic energy to a wide area and effectively shear 20 sample tubes at one time.” He adds, “This is a high throughput solution for labs that need to process many samples per day.”
Optimizing the options
The features that matter the most in an ultrasonic liquid processor depend on the user’s needs. “The trending applications vary from industry to industry,” says Kathrin Hielscher, marketing manager at Hielscher Ultrasonics in Teltow, Germany. “In the food and pharma industry, ultrasonic extraction is a hot topic, whilst the paint and coating industry is mostly interested in the nano-size milling and dispersing.” She adds, “Especially demanding tasks, such as those in nanotechnology or biology, often cannot be fulfilled with a traditional mixing device and require a powerful homogenizer that can be precisely controlled.”
In general, says Hielscher, “Sonochemical reactions are a very important field where a lot of research is undertaken by investigating the ultrasonic effects on chemical reaction systems.” She adds, “Power ultrasound and the resulting shear forces can create unique results in chemical systems, including the initiation of reactions or the change of reaction paths.” When a scientist is working on catalytic reactions and synthesis, Hielscher points out, “the use of ultrasonic homogenizers enables the achievement of higher yields, more complete conversions, faster reaction speed, and/or [fewer] byproducts.” As the search for efficiency expands in research and manufacturing, scientists and technologists will grow even more interested in getting more of want they want—yield—and less of what they don’t—byproducts.
With the expanding expectations of this technology, it must continually make a better fit with more applications and industries. As Hielscher explains it: “The standards of lab homogenizers adapt more and more to the intelligence of industrial machinery.” As an example, she notes that scientists can use a browser to remotely control Hielscher’s digital ultrasonicators, and these products also include automatic data recording and automatic shut-off after a determined time or energy input. The user can also program processing that is punctuated with pauses during the homogenization process. To track the sample conditions more carefully, the user can add plug-in temperature or pressure sensors. As Hielscher concludes, “These functions assure the highest process control, reliable and reproducible sonication results, user-friendliness, and working comfort.”
Picking your processor
When asked what features of an ultrasonic liquid processor matter most, Gupta says, “controllability of the input power.” As someone who works on medicine, renewable energy, and more, Gupta needs to make sure that his samples experience the force that he wants, and that he can repeat that force.
To ensure you get an ultrasonic liquid processor that keeps providing the performance that your lab needs, get one that is guaranteed. For instance, Lustig says, “We are able to offer a two-year warranty because we are so confident in our products. We design, develop, and manufacture everything in house, so we know it’s done right.” He adds, “All facets of manufacturing are certified by a third party to ensure we meet international safety and quality requirements.”
In addition to a guarantee, though, get the product that does what you need it to do. When asked what a lab manager should look for, Lustig says, “Most important is that they buy the correct unit and probe size to match their application and sample volume, and for this they should consult with the manufacturer.” As he says, “Using the incorrect size probe will make it difficult to process samples effectively, and this wastes time and often ends up with the customer having to purchase additional accessories afterward.”
Hielscher even suggests a set of questions to answer before going shopping:
- What is your target application?
- What is the typical volume that must be processed?
- What are the critical factors of the process?
- What are the quality standards that must be achieved?
If you don’t know the answers to these questions, or the best way to incorporate ultrasonic liquid processing in to your lab or company, some vendors can lend a hand. As Hielscher says, “To help our customers during process development and scale-up, [we] offer in-depth consulting on ultrasonic processes, and we train customers at their facilities or in our ultrasonic process lab and technical center.”
When answering the questions on your shopping list, err on the high side. For example, it’s better to get a device that can scale up a little if needed than one that cannot. Otherwise, you could end up shopping again much sooner than you’d like. And maybe it’s just me, but I much prefer a “one and done” approach—getting the right device the first time, and one that lasts a long time.
How Ultrasonic Homogenizers Stack Up
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For additional resources on homogenizers, including useful articles and a list of manufacturers, visit LabManager.com/homogenizers