Columbia University engineers say they have harnessed the molecular machinery of living systems to power an integrated circuit from adenosine triphosphate (ATP). The scientists, led by Ken Shepard, professor of electrical and biomedical engineering, achieved this by integrating a conventional solid-state complementary metal-oxide-semiconductor (CMOS) integrated circuit with an artificial lipid bilayer membrane containing ATP-powered ion pumps. Their work opens the door to creating entirely new artificial systems that contain both biological and solid-state components. “In combining a biological electronic device with CMOS, we will be able to create new systems not possible with either technology alone,” says Shepard.

To build a prototype of their hybrid system, Shepard’s team, led by Ph.D. student Jared Roseman, packaged a CMOS integrated circuit with an ATP-harvesting “biocell.” In the presence of ATP, the system pumped ions across the membrane, producing an electrical potential harvested by the IC.

Biocell attached to CMOS integrated circuit with membrane containing sodium. Image credit: Trevor Finney and Jared Roseman.Biocell attached to CMOS integrated circuit with membrane containing sodium. Image credit: Trevor Finney and Jared Roseman. “We made a macroscale version of this system, at the scale of several millimeters, to see if it worked,” Shepard says. “Our results provide new insight into a generalized circuit model, enabling us to determine the conditions to maximize the efficiency of harnessing chemical energy through the action of these ion pumps. We will now be looking at how to scale the system down.”

While other groups have harvested energy from living systems, Shepard and his team are exploring how to do this at the molecular level, isolating the desired function and interfacing this with electronics. “We don’t need the whole cell,” he says. “We just grab the component of the cell that’s doing what we want. For this project, we isolated the ATPases because they were the proteins that allowed us to extract energy from ATP.”

The ability to build a system that combines the power of solid-state electronics with the capabilities of biological components has great promise. “You need a bomb-sniffing dog now, but if you can take just the part of the dog that is useful—the molecules that are doing the sensing—we wouldn’t need the whole animal,” says Shepard. “With appropriate scaling, this technology could provide a power source for implanted systems in ATP-rich environments such as inside living cells,” adds Roseman.

Despite his success in developing engineered solid-state systems interfaced to biological systems, Shepard notes that CMOS solid-state electronics is incapable of replicating certain functions natural to living systems, such as the senses of taste and smell and the use of biochemical energy sources. They achieve this functionality with their own version of electronics based on lipid membranes and ion channels and pumps, which act as a kind of “biological transistor.”

Living systems use charge in the form of ions to carry energy and information; ion channels control the flow of ions across cell membranes. By contrast, solid-state systems, such as those in computers and communication devices, use electrons; their electronic signaling and power are controlled by field-effect transistors.

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