Researchers at Penn State University have made a significant breakthrough in the field of particle manipulation using acoustic waves.
While scientists have been able to separate particles based on their shape, controlling their movement has proven tricky until now. To this end, the team at Penn State has developed a microchannel nozzle and applied ultrasound energy to the system, enabling them to concentrate fluid flow and reflect acoustic waves.
By working with nanorods, synthetic self-propelled particles, the researchers demonstrated their ability to separate, aggregate, and eject particles based on their shape and properties. The nanorods were placed in a nozzle, and with the addition of hydrogen peroxide, they imitated the swimming behavior of bacteria. Ultrasound and fluid flow were then used to separate the nanorods, aggregate them, or extrude them from the nozzle. This level of control in particle separation is groundbreaking and has implications for various technologies, including 3D printing and drug delivery.
“The separation concept relies on the fact that nanorods and spherical particles have different responses to acoustic radiation and generated fluid flow,” said corresponding author Igor Aronson.
“By controlling the nozzle shape and the frequency and amplitude of the acoustic radiation, we can coerce particles of different shapes and material properties to behave differently. This, especially, applies to active particles such as nanorods: They can swim autonomously, and their control is especially challenging.”
The researchers envision applications such as selectively depositing nanorods in 3D printed objects to alter their properties and using acoustic nozzles for bioprinting, allowing for precise control over cell types. The ability to separate bacteria from cells could also be valuable in targeted drug delivery. The study was supported by the U.S. Department of Energy.
You can read the research paper in full, at this link.
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