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A special printer loaded with silver nanoparticles, silicone and living cells can print a three-dimensional bionic ear with functional electronics.

Credit: MANU S. MANNOOR

Michael McAlpine at Princeton University in New Jersey and his colleagues used a computer to design a human-sized 'ear' with a spiral antenna and electrodes shaped like the cochlea of the inner ear. The printer made the device by building up all the materials layer by layer, encasing the electronics in a hydrogel scaffold seeded with specialized cells. The structure was placed in a nutrient broth to grow the cells into cartilage.

Although the bionic ears do not detect sound waves, they can receive radio signals at frequencies within and beyond the normal range of hearing through the cartilage-covered antenna. The work shows that wet, squishy biological materials can be interwoven with functioning electronics even in complex structures, the authors say.

Nano Lett. 13, 2634–2639 (2013)