Whether it's Velcro or aircraft design, engineers have a long tradition of lifting some amazing design concepts from Mother Nature. A new paper by researchers at Yale University and the National Institute of Standards and Technology (NIST) takes this idea to a cellular level. Applying modern engineering design tools to one of the basic units of life, they argue that artificial cells could be built that not only replicate the electrical behavior of electric eel cells, but improve on them. Artificial versions of the eel's electricity-generating cells could be developed as a power source for medical implants and other tiny devices, say researchers.
Electric eels channel the output of thousands of specialized cells called electrocytes to generate electric potentials of up to 600 volts, according to biologists. The mechanism is similar to nerve cells. The arrival of a chemical signal triggers the opening of highly selective channels in a cell membrane, causing sodium ions to flow in and potassium ions to flow out. The ion swap increases the voltage across the membrane, which causes even more channels to open. Past a certain point, the process becomes self-perpetuating, resulting in an electric pulse traveling through the cell. The channels then close and alternate paths open to “pump” ions back to their initial concentrations during a “resting” state.
In principle, say the authors, stacked layers of artificial cells in a cube slightly over 4 mm on a side are capable of producing continuous power output of about 300 microwatts to drive small implant devices. Like the natural counterpart, the cell's energy source would be adenosine triphosphate (ATP), synthesized from the body's sugars and fats using tailored bacteria or mitochondria.
