Montreal (Canada) According to a press release, a team of researchers from Concordia University has developed a novel 3D printing process that can be used to additively build objects in the human body. They recently presented their work entitled “Direct sound printing” in the Nature journal (doi: 10.1038/s41467-022-29395-1).
The process, called Direct Sound Printing (DSP), uses polydimethylsiloxane (PDMS) resin, a silicon-based polymer that is cured with sound waves.
The resin is contained in a container into which ultrasonic waves are sent using a transducer. This creates small bubbles that vibrate at high speed. A temperature of 14,727 degrees Celsius and a pressure of over 1,000 bar are reached in the bubbles. The increase in pressure and temperature does not affect the surrounding material because it lasts only a few picoseconds. However, this time is sufficient for the PDMS to solidify.
“We found that if we use a certain type of ultrasound at a certain frequency and power, we can create very local, very focused chemically reactive regions. The bubbles can be used as reactors to stimulate chemical reactions that turn liquid resin into solid or semi-solid material,” explains Mohsen Habibi who works at the Optical Bio Microsystems Laboratory at Concordia University.
The developers assume that the method is particularly suitable for medicine. An implant could thus be printed directly in the body. The building material is injected into the body and then solidified with the ultrasonic transducer. The non-toxic PDMS is already used in medicines. Ceramics can also be processed with DSP.
The ultrasonic transducer of the 3D printer moves on fixed paths. He builds the object pixel by pixel. Depending on the duration of the ultrasonic wave frequency and the viscosity of the raw material, objects with different properties can be printed.
“Next we will try polymer-metal composites, and eventually we want to print metal with this method as well,” explains Habibi’s colleague Muthukumaran Packirisamy.