May 3, 2013

Scientist Create Ear that Hears

(The following appeared written by DEBORAH NETBURN appeared in The LA Times May 2, 2013, 9:49 p.m)

Need a new ear? In the future you may be able to print one out and pop it on.

Taking us one step closer to a future in which we are all part human, part machine, scientists at Princeton University have created a pair of high functioning bionic ears made of a mix of cellular material, silicone and electronics and printed them using a $1,000, off-the-shelf, 3-D printer.

The “designer cyborg ears,” as the researchers call them, look a lot like regular ears but have the potential to hear frequencies way beyond the reach of normal human hearing.

And the process by which they were created suggests that, 3-D printing may become the best way to integrate electronic materials with biological tissues.

A 3-D printer works by layering materials on top of each other in thin layers, forming a physical — three-dimensional — representation of a computer model.

To create the ears, lead researcher Michael McAlpine and his team fed three materials into a 3-D printer: a hyrdrogel matrix made with calf cartilage cells to provide the ears’ structure, a conductive silver nano-particle to create the coiled receiver in the ear, allowing it to “hear,” and silicone to wrap around the electronics.

After the ears were printed, researchers submerged them in a solution that encouraged the calf cells to grow cartilage around the electronics, naturally embedding it.

In a paper accepted for publication by Nano Letters, the researchers write that the ear held its shape throughout this process, and over time, grew more opaque as the cartilage grew.

The picture above shows an ear about 10 weeks after it was printed, which is about how long it takes for the ear to reach maturity, McAlpine said in an interview with the Los Angeles Times.

This team’s first pair of 3-D printed ears can only receive radio waves, but future ears could incorporate other materials — such as pressure-sensitive electronic sensors — that would allow them to register acoustic sounds.

The sound the ears “hear” could be transmitted to a person via wires that would connect the base of the bionic ear to the human’s nerve endings, similar to the way some hearing aids work.

More testing and research are needed, but McAlpine said it might be possible within the next 10 years to get your very own usable 3-D printed ear.

And keep your eye out for other 3-D printed smart organs coming from his group, he said.

“Ultimately it would be nice to print a bionic human, and grow it in a petri dish,” he said, “but there are obviously some challenges to doing that.”