(a) Illustration
depicting biocell attached to CMOS integrated circuit. (b) Illustration
of membrane in
pore containing sodium–potassium pumps.
(December 7, 2015) System
combines biological ion channels with solid-state transistors to create a new
kind of electronics.
Columbia Engineering researchers have, for the first time,
harnessed the molecular machinery of living systems to power an integrated
circuit from adenosine triphosphate (ATP), the energy currency of life. They
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, opening the door to creating
entirely new artificial systems that contain both biological and solid-state
components. The study, led by Ken Shepard, Lau Family Professor of Electrical
Engineering and professor of biomedical engineering at Columbia Engineering, is
published online Dec. 7 in Nature Communications.
“In combining a biological electronic device with CMOS, we
will be able to create new systems not possible with either technology alone,”
says Shepard. “We are excited at the prospect of expanding the palette of
active devices that will have new functions, such as harvesting energy from
ATP, as was done here, or recognizing specific molecules, giving chips the potential
to taste and smell. This was quite a unique new direction for us and it has
great potential to give solid-state systems new capabilities with biological
components.”
Shepard, whose lab is a leader in the development of
engineered solid-state systems interfaced to biological systems, notes that
despite its overwhelming success, 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. Living systems
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.” They use charge in the form of ions to carry energy and
information—ion channels control the flow of ions across cell membranes.
Solid-state systems, such as those in computers and communication devices, use
electrons; their electronic signaling and power are controlled by field-effect
transistors.
In living systems, energy is stored in potentials across
lipid membranes, in this case created through the action of ion pumps. ATP is
used to transport energy from where it is generated to where it is consumed in
the cell. To build a prototype of their hybrid system, Shepard’s team, led by
PhD student Jared Roseman, packaged a CMOS integrated circuit (IC) 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.