Robots with moveable arms are nothing new. You’ll see them in factories, carrying out lots of different jobs. With special programming, one robot can do many tasks at the same time!
Until recently, robots with arms were unable to properly interact with microfluidic systems that are specialized for transferring tiny drops of liquid through thin tubes. These systems are known as “lab-on-a-chip” and they need special pumps to keep the liquid flowing. However, making them work in an automated way was hard because the chips had to be customized for each application.
Combining Robotics and Microfluidics for Microscopic Applications
Scientists led by Professor Daniel Ahmed from ETH have created a special device. This device is composed of both robotics and microfluidics and can be connected to a robotic arm. This invention is very helpful because it can accomplish many tasks for microrobotic and microfluidic applications, as well as automate such activities. The scientists reported their success in Nature Communications publication.
The device has a small and pointy glass needle attached to something called a “piezoelectric transducer”. This transducer is also used in speakers, ultrasound machines, and some professional dental cleaning equipment. With this device, scientists at ETH can change the speed of the needle’s vibration. By dipping the needle into liquid, they can create a 3D pattern of swirling eddies that all depend on how fast or slow the needle vibrates.
The researchers were able to do some cool stuff. They used their method to mix two liquids, even when one of them is like really sticky and hard to move around. Professor Ahmed said it works because they create a special 3D pattern made with lots of swirling vortices, making this possible.
Next, the scientists figured out a way to get liquids to go through tiny channels. They achieved this by making currents that twisted and turned in a certain pattern and then positioning a shaking glass needle near the side of the channel.
The researchers’ robot-assisted acoustic device captured small particles that were trapped in the fluid. This worked because, depending on their size, the particles would move towards an oscillating glass needle which they could then accumulate. They were even able to use this method to capture not only solid objects but also fish embryos! Ahmed said that it would work for capturing other biological cells too. “With our microrobotic arm, manipulating particles in three dimensions is so much easier!”
Scientists have made a breakthrough which can combine two technologies – large robotic systems and microfluidic applications. This means that future microfluidic chips won’t need to be redesigned for each application. All the tasks like mixing, pumping liquids and trapping particles can all be done by these new devices. Researchers would also like to add multiple needles together in order to make even more complex patterns in liquid.
Ahmed is thinking of other ways that his microrobotic arms can be used for like sorting small objects, inserting DNA into single cells, and 3D printing. All these activities will soon be doable with his invention.
Reference: “A robot-assisted acoustofluidic end effector” by Jan Durrer, Prajwal Agrawal, Ali Ozgul, Stephan C. F. Neuhauss, Nitesh Nama and Daniel Ahmed, 26 October 2022, Nature Communications.DOI: 10.1038/s41467-022-34167-y
