Scientists showcase new technology to assemble matter in 3D using sound waves for 3D printing
Scientists from the Micro, Nano and Molecular Systems Lab at the Max Planck Institute for Medical Research and the Institute for Molecular Systems Engineering and Advanced Materials at the University of Heidelberg have developed a new technique for assembling matter in 3D. Their concept uses multiple acoustic holograms to generate pressure fields that can be used to print solid particles, gel beads, and even biological cells. These results pave the way for new 3D cell culture techniques with applications in biomedical engineering.Research results published in a journal scientific progress February 8th.
Additive manufacturing or 3D printing can produce complex parts from functional or biological materials. Traditional 3D printing creates objects one line or layer at a time, which can be a slow process. Researchers from Heidelberg and Tübingen demonstrate how to form his 3D objects from small building blocks in just one step.
“Using shaping ultrasound, we were able to assemble microparticles into three-dimensional objects in a single shot,” said Kai Melde, a postdoc in the group and lead author of the study. “This is very useful for bioprinting, where the cells used are particularly sensitive to the environment during the process,” adds Professor Pier Fischer of the University of Heidelberg.
Sound waves exert forces on matter. This is a fact known to any concert-goer who has experienced pressure waves from loudspeakers. Using high-frequency ultrasound, which is inaudible to the human ear, he can squeeze wavelengths into microscopic regions of less than a millimeter. It is used by researchers to manipulate very small building blocks such as living cells.
In previous work, Pia Fischer and colleagues showed how to shape ultrasound using acoustic holograms (3D-printed plates) made to encode specific sound fields. They demonstrated that those sound fields can be used to assemble materials into two-dimensional patterns. Based on this, scientists have devised a manufacturing concept.
New research allowed the team to take the concept one step further. It captures particles and cells that float freely in water and assembles them three-dimensionally. What’s more, the new method works with a variety of materials, including glass, hydrogel beads, and living cells. “The key idea was to use multiple acoustic holograms together to form a composite field that could catch particles,” says lead author Kai Melde. Hologram Heiner Kremer, who created an algorithm that optimizes the field, adds:
Scientists believe their technology is a promising platform for shaping cell cultures and tissues in 3D. The advantage of ultrasound is that it is gentle on living cells and can reach deep into tissue. In this way it can be used to manipulate and push remotely without harming the cells.
Original: Create 3D objects with sound
Than: Max Planck Institute for Medical Research | University of Heidelberg
