Scientists have developed an innovative method for moving objects with sound, which could revolutionise applications in medicine.
Researchers at the Ecole Polytechnique Fédérale de Lausanne (EPFL) have directed floating objects around an aquatic obstacle course using only soundwaves. This optics-inspired technique involves a method that relies on soundwaves to move objects without needing controlled environments or direct contact.
The approach shows great promise for noninvasive targeted drug delivery, potentially allowing precise delivery of medications to specific areas within the body.
A Novel Method: Wave Momentum Shaping
The EPFL team, led by Romain Fleury, has developed a technique called wave momentum shaping. This method leverages soundwaves to move objects precisely, overcoming limitations of traditional optical tweezers.
Optical tweezers, which use laser beams to trap and manipulate microscopic particles, require highly controlled and static environments. In contrast, wave momentum shaping can function effectively in dynamic and uncontrolled settings.
Fleury explains, “In our experiments, instead of trapping objects, we gently pushed them around, as you might guide a puck with a hockey stick.” This ability to manoeuvre objects without needing stable conditions opens new possibilities for various applications, especially in medicine.
How Wave Momentum Shaping Works
Wave momentum shaping operates by using soundwaves to apply precise forces on objects, allowing them to be moved along predetermined paths. In the experiments conducted by the EPFL team, an overhead camera tracked the position of a floating object, such as a ping-pong ball, on the surface of a water tank.
Arrays of speakers emitted audible soundwaves from either end of the tank to guide the ball along a set path. A second array of microphones listened to the feedback, known as the scattering matrix, which provided real-time data on the ball’s position and the optimal momentum required to move it.
Advantages Over Traditional Methods
Traditional methods like optical tweezers require highly controlled environments to trap and manipulate particles. These methods often struggle in dynamic or disordered settings. Wave momentum shaping, however, does not have these limitations.
It relies solely on real-time positional data and the scattering matrix, making it adaptable to various environments. Fleury emphasises, “The method is rooted in momentum conservation, which makes it extremely simple and general, and that’s why it’s so promising.” This simplicity and adaptability make wave momentum shaping a versatile tool for many applications.
Potential Biomedical Applications
One of the most promising applications of moving objects with sound is in the field of medicine, particularly for noninvasive targeted drug delivery. Current drug delivery methods struggle with precision. This sometimes leads to side effects as the drugs affect areas beyond the target site.
Wave momentum shaping could solve this issue by allowing precise delivery of medications directly to specific cells or tissues. Fleury notes, “Some drug delivery methods already use soundwaves to release encapsulated drugs, so this technique is especially attractive for pushing a drug directly toward tumour cells, for example.” This method could also revolutionise tissue engineering and biological analysis, where touching cells directly could cause damage or contamination.
Practical Demonstrations and the Future
In their experiments, the researchers successfully navigated a ping-pong ball around both stationary and moving obstacles, demonstrating the method’s effectiveness in dynamic environments. They even managed to control the rotation of more complex objects, such as an origami lotus. This showcases the technique’s versatility.
Future experiments aim to scale this method from macroscopic objects to microscopic ones, potentially using ultrasonic waves to manipulate cells. Fleury and his team have already received funding to conduct experiments under a microscope, bringing them one step closer to revolutionising drug delivery and other biomedical applications.
Moving Forward with Soundwave Technology
The EPFL team’s breakthrough in moving objects with soundwaves marks a significant advancement in the field. By harnessing the principles of wave momentum shaping, researchers have created a versatile, noninvasive method for object manipulation.
This innovative approach holds immense potential for improving drug delivery, tissue engineering, and numerous other biomedical and industrial applications. As Fleury and his team continue to refine their technique, the future looks promising for soundwave-based manipulation, offering new possibilities for precise, controlled movement of objects in various settings.
References
- Moving objects precisely with sound. (2024, June 24). ScienceDaily. https://www.sciencedaily.com/releases/2024/06/240625205634.htm Orazbayev, B., Malléjac, M., Bachelard, N., Rotter, S., & Fleury, R. (2024). Wave-momentum shaping for moving objects in heterogeneous and dynamic media. Nature Physics. https://doi.org/10.1038/s41567-024-02538-5
