3-D Printed Circuitry Could Be Just Around the Corner

As the days go by we continue to hear more stories about the vast capabilities of 3-D printing technology--from printing working medical devices such as vein finders, to producing actual viable blood vessels from 3-D printing technology. Now, Princeton University researchers are looking to expand the technology a step further by exploring the potential to print functioning electronic circuitry out of semiconductors and other materials.

The idea is to eventually use biocompatible materials and even living tissue, paving the way for exotic new biomedical implants, according to an MIT Technology Review article about the research. The research has been led by assistant professor Michael McAlpine, who last year used a 3-D printer to produce a "bio-electronic" ear.

Typically, processors and display circuitry inside a computer don't lend themselves to 3-D printing because they require many complex components that are created on the nanoscale. However, McAlpine believes 3-D printing technology could be used to make medical devices and implants that incorporate electronics. He notes that researchers can already print a scaffold for growing nerve tissues. If his team could also print LEDs and circuits within the scaffold, the light could stimulate the nerves, while the electronics could be used to interface with a prosthetic limb.

Since McAlpine printed the first bio-electronic ear last year, his group has been working tirelessly to expand the capabilities of 3-D printing technology to involve semiconducting materials that would allow a printed device to process incoming sounds. Semiconductors serve as a key component of information-processing circuits, and can also be used to detect and emit light. To help broaden their horizons, McAlpine's group even built their own printer to help them print in higher resolution, and with different materials.

To produce the LEDs, researchers chose to use quantum dots. These quantum dots are semiconducting nanoparticles that emit very bright light in response to electrical currents. They also used two different kinds of metal to make electrical leads and contacts for the devices, as well as polymers and a silicone matrix to hold it all together.

So far, producing the LED is just a small piece of the puzzle of 3-D printing active electronics, McAlpine said. Once researchers can print active electronic materials, they should be able to produce information-processing circuits, light detectors, sensors, and other elements that can be integrated with biological tissue.

Despite the many different challenges involved with 3-D printing electronics, strides are being made across the globe to address the issues as researchers look for significant breakthroughs.

While McAlpine and his group continue to utilize their new technique to refine and customize biomedical devices, they're on the brink of testing the efficiency of these new devices in various animal studies. While we await the publication of the full details of his work, McAlpine says he's also begun work on creating complex electronic devices that use actual living cells. If successful, his work could prove to add a whole new element to the potentials of 3-D printing technology. 

Kristopher Sturgis is a contributor to Qmed and MPMN.

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