Sound Technology Enables Precise Object Movement

Optical tweezers have long been used to manipulate particles by creating a light 'hotspot' to trap them, akin to a ball falling into a hole. However, according to Romain Fleury, head of the Laboratory of Wave Engineering at EPFL, this method faces challenges when there are other objects nearby, making it difficult to create and control the trapping hole.

Fleury, along with postdoctoral researchers Bakhtiyar Orazbayev and Matthieu Malléjac, has dedicated the past four years to developing a groundbreaking approach to moving objects in dynamic environments using soundwaves. Their innovative technique, known as wave momentum shaping, is remarkably versatile as it does not depend on an object's surroundings or physical characteristics. All that is needed is the object's position, and the soundwaves take care of the rest.

"In our experiments, instead of trapping objects, we gently pushed them around, similar to guiding a puck with a hockey stick," Fleury elaborates on their unconventional method.

The team's research, supported by the Swiss National Science Foundation (SNSF) Spark program, has been published in Nature Physics in collaboration with experts from the University of Bordeaux, Nazarbayev University, and the Vienna University of Technology. Fleury highlights the potential of this technique in drug delivery, particularly for directing drugs precisely towards target cells, such as tumor cells.

Besides its applications in drug delivery, the wave momentum shaping method holds promise in fields like biological analysis and tissue engineering, where traditional manipulation techniques could lead to cell damage or contamination. Fleury envisions using this method in 3D printing to arrange microscopic particles before solidifying them into a desired structure.