Surgeons won't be shrunk and sent into the body like in the 1960s Sci-Fi, Fantastic Voyage, but could program a specialised array of mini-speakers to create an intricate sound field that 'traps' and manipulates selected objects in ‘acoustic tweezers’ for manipulation within tissue.
Advancements in acoustic tweezers from Professor Bruce Drinkwater in the Department of Mechanical Engineering, University of Bristol, and his colleague Dr Asier Marzo, from Universidad Publica De Navarra in Spain, are driving the technology towards this futuristic-sounding reality. The team's recent developments published today (Monday 17 December) in the Proceedings of the National Academy of Sciences (PNAS), demonstrate for the first time the acoustic levitation and manipulation of multiple objects simultaneously.
Professor Drinkwater envisions an iteration of this system eventually being used to acoustically stitch up internal injuries or deliver drugs to target organs. He said: "Now we have more versatility - multiple pairs of hands to move things and perform complex procedures, it opens up possibilities that just weren’t there before."
Dr Marzo explained: "We applied a novel algorithm that controls an array of 256 small loudspeakers - and that is what allows us to create the intricate, tweezer-like, acoustic fields."
Another advantage is that acoustic devices are 100,000 times more power efficient than optical systems. Professor Drinkwater explained: "Optical tweezers are a fantastic technology, but always dangerously close to killing the cells being moved, with acoustics we’re applying the same sort of forces but with way less energy associated. There’s lots of applications that require cellular manipulation and acoustic systems are perfect for them."
To demonstrate the accuracy of their system, the scientists attached two millimetric polystyrene spheres to a piece of thread and used the acoustic tweezers to "sew" the thread into a piece of fabric. The system can also simultaneously control the 3D movement of up to 25 of these spheres in air.
Dr Marzo explained: "The flexibility of ultrasonic sound waves will allow us to operate at micrometre scales to position cells within 3D printed assemblies or living tissue. Or on a larger scale, to levitate tangible pixels that form a physical hologram in mid-air."
This project has been funded by the UK Engineering and Physical Science Research Council (EPSRC).