Scientists have invented a device that uses intense sound waves to levitate tiny objects and move them without any direct contact, a technique that has been captured in surreal footage of small sticks, beads, and droplets suspended eerily in the air, as if enchanted.
The device, called LeviPrint, pioneers a new technique for contactless manufacturing, and debuts an unprecedented manipulation of elongated objects, according to research published on Wednesday that will be presented at the SIGGRAPH conference in Vancouver, British Columbia, this August.
Videos by VICE
LeviPrint’s ability to move such small objects, and even liquid droplets, can enable microfabrication of small machines, like watches or camera parts, without risking cross-contamination as a result of direct content. It may also prove useful for bio-engineering because the device “could assemble microscopic objects in cell-culture media and perhaps even inside living beings,” according to the new study.
“Contactless fabrication allows for less cross-contamination, manipulating a wide variety of parts (beads, liquids, sticks, powders…) and moving those parts through holes and cavities,” said Asier Marzo, a researcher at the Public University of Navarre who co-authored the study, in an email. “For example, we built a tiny boat inside a bottle made of metallic mesh by inserting all the components through a small aperture at the side.”
While many teams have experimented with acoustic levitation, a technique that uses the pressure of sound waves to suspend matter, Marzo and his colleagues are the first to combine the manipulation of small particles and droplets into a full prototype for contactless fabrication. LeviPrint is also the first device that uses acoustic traps to suspend elongated objects, which could be useful for manufacturing processes that require beams, sticks or girders. While these tests were performed with air as a medium, there are even more exotic possibilities in water.
“Most of the coolest applications are when operating in water-based media instead of air,” Marzo said. “The same techniques that worked in air, could translate directly to water-based media. In fact, it is easier since objects weigh less and the ultrasound travels better through water.”
“The LeviPrint technique could control the orientation of elongated objects inside the body like needles, or tiny probes,” he added, though he noted that the team still needs to develop device emitters that are adapted to perform in water.
While there is solid science underpinning LeviPrint, the bizarre footage of its abilities makes it look like the team is casting a spell. It’s an impression that is not lost on Marzo and his colleagues, even though they have invested years in the nuts-and-bolts of the device.
“The first time you levitate something it’s quite a magical experience, especially when your childhood is full of wizards or sci-fi movies,” Marzo said. “You start slowly moving the element around and observing it from all angles, like focusing all your attention on a magic trick. But you get used to it quickly, and you want to levitate more and more complex stuff and perform faster and more complex movements, searching for the limits of the system.”
“The limitations that we found on previous devices are a big motivation to create something that could go further,” he added. “We admit that after the last years, we have become quite used to manipulating levitated samples, doing it manually can be a bit tricky since your hand shakes and that vibration can become resonant with the trapped particle. It is like that game of running with an egg on a spoon. So, when we switched to the robotic arm, it was a big relief given its accuracy, speed and the lack of any shakiness.”
In addition to presenting their research later this summer, Marzo and his colleagues hope that other scientists will adopt and adapt LeviPrint for a range of functions.
“The device that we used was a prototype assembled by a couple of researchers that are not experts in electronics, but it was enough to showcase the techniques and hint for potential applications,” Marzo concluded. “Now, a big engineering company can manufacture more powerful and accurate levitators that would provide more precision and the capability to work with materials such as aluminum or even steel. We hope to see a research group with experience in biomedical applications that adopt this technique to operate in water-based media and biomaterials.”
