Transistors are at the heart of every gadget — but as futurist Ray Kurzweil once predicted, "Our computers aren't going to be these distinct rectangular devices we carry around. We are going to merge with them."
Noy designed a new nanotube transistor after living cells. As biological systems depend on membrane receptors to communicate and have specialized channels and pumps to send signals, they have a leg-up on traditional electronics.
Contemporary gadgets communicate through an electric field and depend on currents to transmit data. Obviously, if the electronics were outfitted with biological components, they would be a lot more efficient.
Enter the hybrid transistor - half biological, half machine. In order for the transistor to behave like a cell, it must be built like a cell. So Noy gave his nanotube a cell membrane.
Made with two metal electrodes, the nanotube is coated with an insulating polymer layer with a hollow center. After applying one more coat around the transistor, it cleverly mimicked the lipid bi-layer structure in cell membranes.
But the membrane would be just a membrane without adenosine triphosphate (ATP), the energy currency in living cells. Noy used ATP to power the hybrid bionanoelectronic transistor. After applying voltage to the electrodes, the scientists covered the transistors with ATP, potassium and sodium ions — a current ran through the nanotube system.
Basically, the new transistor takes advantage of the energy generated when the ions move between the electrodes. The current strength fluctuates depending on the concentration of the ATP. Also when ions build up, an electric field is generated at the center of the nanotube.
"The ion pump protein is an absolutely critical element of this device," says Noy [of Lawrence Livermore National Lab]. "Each cycle, it hydrolyses an ATP molecule and moves three sodium ions in one direction and two potassium ions in the opposite direction." This results in the net pumping of one charge across the membrane to the nanotube. [New Scientist]
Imagine what it would be like if electronics operated like cells. The electronics could stay inside our bodies without batteries — all thanks to ATP. Improving communication at a localized level would improve biosensing and diagnostic tools. And computers would become more efficient if biological components made their way into transistors.
Of course, prosthetic devices would benefit tremendously. For instance, our ears convert sound waves into nerve impulses effortlessly, so why not design cochlear implants with biological parts. Ultimately we'd want devices hooked up directly to the brain. Or do we?
Image by Scott Dougherty, LLNL