In the 1980s, Japanese consumer electronics manufacturer, Maxell, produced an advertisement that became widely known as “Blown Away Guy.” In the commercial, a man is sitting in a high-armed chair in front of a speaker wearing all black clothes and sunglasses. Next to him are a lamp and a table with a martini glass. A butler walks up and asks, “The usual, sir?” The man responds, “Please,” and when the tape begins to play, the sound waves from the speaker blow his hair and tie back, as well as the lamp and martini glass (which he places his hand on before it falls).
While this 30-second commercial exaggerates the strength of the sound coming from the Maxell speaker, the ability for sound waves to exert enough power to produce movement such as this is more than possible. In fact, it is this strength and movement that John Rozembersky, VP of biological filtration at FloDesign Sonic, and his colleagues depend on for their acoustic wave cell removal technology, which is accomplished through a three-dimensional standing wave. And if you’re not familiar with the term, you’re most likely familiar with the experience.
If you’ve ever walked out into an ocean, you’ve felt the impact of waves propagating on the surface of the water. Hit from the back and you fall forward; hit from the front and you’ll find yourself face first in the water. However, in very choppy waters, you could potentially get hit from the front by waves coming from the sea, while simultaneously being hit from the back by waves bouncing off of the shore line. If these waves are timed correctly, the equal and opposite forces could trap you in a stable position; this is referred to as a standing wave. FloDesign Sonic uses a specially-designed, 3D version of a standing wave to act as an invisible barrier (or filter) to catch cells while the remaining liquid and materials pass through. The cells group inside the standing wave and precipitate out of the fluid flow, where FloDesign Sonic uses specially-designed fluidics to continuously draw off the concentrated cells.
Common practice today is for this process to be completed through centrifugation and depth filtration. However, it presents challenges that will become more of an issue as technology and science create biologics with a higher cell mass. “The industry has gone from having a few hundred thousand cells per milliliter up to as high as 40 million cells per milliliter of material, so the amount of solid material we have to pull out is going up,” says Rozembersky. “With depth filtration, the more material you have to put through filters, the bigger the filter you’ll need. These filters are going from manageable sizes to really large sizes, which can be very expensive.” The cost to clarify 1,000 liters at a typical cell density of 5-10 million cells per milliliter can range from $15,000 to $20,000 in filters, which need to be replaced after each use. To clarify 30 to 40 million cells per milliliter, this cost can sky rocket to more than $100,000.