Researchers at the Stevens Institute of Technology in New Jersey have used 3D printing to fabricate the first ever bionic mushroom. The structure, which is made from an ordinary button mushroom whose cap is patterned with energy-producing cyanobacteria and graphene nanoribbons printed alongside the bacteria, is capable of generating around 65 nanoamps of current. While not enough to power an electronic device, an array of such mushrooms could provide enough current to power a light-emitting diode.
Cyanobacteria have unparalleled internal quantum efficiency, with almost 100 percent conversion of photosynthetic energy - the result of 2.5 billion years of evolution, he explained. These organisms are nature's most efficient antenna systems, which absorb photons from the sun and systematically guide them to the reaction center (made of enzymes), followed by charge separation (electrons and holes). This separation in space means that they cannot neutralise each other through charge recombination, so electrons can generate light currents.
Densely-packed cyanobacterial cells
Thanks to 3D printing, the team was able to anisotropic assemble denser cyanobacteria cells on the mushrooms' porous structure.
At these contact points, electrons are transferred through the cyanobacteria 'outer membrane to a conductive network of graphene nanobarbors as we shine light on the mushrooms.This activates the photosynthesis of bioelectrons in cyanobacteria, which then apply bias voltage to electrochemical devices to drive the electrons.