Shock waves can control how particles organize themselves. Although researchers have been able to separate different things based (Researchers use ultrasound to control the orientation of small objects) on their nature – say, bacteria from other cells – for years, the ability to control their movement has remained an unsolved problem until now. Using ultrasonic technology and a nozzle, Penn State researchers separated, controlled, and removed different materials based on their shape and properties.
They published their results in the journal Small. “We designed a microchannel nozzle and added ultrasound energy to the system,” corresponding author Igor Aronson, Penn State Dorothy Foehr Huck and J. Lloyd Huck Professor of Biomedical Engineering and Professor of Chemistry said. “The musician performs two tasks. He concentrates on the installation of water, which other researchers have done. But on top of that, the wall of the nozzle reflects the sound waves of ultrasonic energy.
Aronson and his collaborators work with tiny materials called nanorods, which are among the most studied self-generating synthetic materials, according to Aronson. Because they are similar in size and have the ability to swim with bacteria, Aronson said, many of the conclusions drawn from the observation of nanorods may be involved in the movement of bacteria. For this reason, they are often used as proof of concept for future division projects.
In this case, the nanorods are half platinum and half gold. The researchers inserted the nanorods into a cavity, which looks like a small syringe, and added hydrogen peroxide. Hydrogen peroxide is broken – or burned – on the platinum half of each nanorod, forcing them to swim in the same way as bacteria. The researchers put ultrasound into the cavity, creating shock waves that, along with the flowing water, can separate the nanorod particles, collect them, or remove them from the nozzle.
“The concept of separation is based on the fact that nanorods and spherical particles have different responses to sound radiation and liquid water,” said Aronson. “By controlling the shape of the nozzle and the frequency and intensity of sound radiation, we can force parts of different types and materials to behave differently. This, in particular, affects the things that -work like nanorods: they can swim automatically and their control is more difficult. »
This level of control over particle separation has not been demonstrated before, according to the researchers. Aronson said the show has implications for future technologies, including additive manufacturing, also known as 3D printing, and drug delivery.
“For 3D printing, the idea is that you can add some additives to the ink, for example nanorods,” he said. “So now we can separate the nanorods from the bright materials to put only a few of them in the print, like a polymer deposit without nanorods and so on, everything to change the properties of the print.”
Aronson said this principle also applies to living cell printing, known as bioprinting.
“Potential applications for bio-printing could include the design of acoustic nozzles for bio-inkjet printers,” he said. “By controlling the amount of radiation in the nozzle, we can exclude certain types of cells – for example, stem cells – and trap others – for example, bacteria. This is another control for bioprints.
This ability could also be useful for isolating bacteria from cells and for targeted drug delivery, Aronson said. The researchers plan to mix bacteria and living cells in the laboratory, isolate and control them.
Source: Pennsylvania State University
