Self-assembling protein promises biocomputing
Star-shaped molecule, Clathrin, self-assembles into nanoscale spheres.
A protein found in human cells holds the promise of self-assembling biocomputing machines—information processing systems of the future that are smaller, faster and cheaper than today's computer circuitry, claims ExQor Technologies Inc.
The company said it has demonstrated that clathrin can be formed into nano-sized biolasers suitable for transmitting information. It expects the technology will initially be used in medical applications. The precision of clathrin's self-assembly process, and small size also could be used to improve solar cells and batteries with nanoscale electronic and photonic properties not possible with silicon.
"Our clathrin scaffolding applications are also dual use, with commercial applications in VLSI lithography, biomolecular electronics and in self-assembling novel photonic nanostructures for alternative energy generation," claimed ExQor founder Franco Vitaliano.
The protein clathrin exists in the cells of most living things as a gate-keeper and signalling system. It sorts and transports chemicals by folding around them as they enter a cell. Individual clathrin subunits, called triskelion, are shaped like a tripod.
In solution, ExQor's synthetic version self-assembles a number of triskelia into 20- to 100nm diameter cages containing "cargo." By functionalizing the triskelia with antibodies or other agents that identify pathogenic conditions like cancer or tissue damage, clathrin cages can carry drugs to specific cells, and then pass inside to deliver them.
Suitable for biocomputing
Since clathrin is a natural gatekeeper in the body, it can readily access most human cells, even safely entering the brain, which normally prevents large molecule drugs from entering.
While researching clathrin for medical applications, ExQor discovered that the material exhibits quantum properties useful for biocomputing applications, including nanoscale lasing.
"When we were first developing the clathrin asymmetric resonant cavity, or ARC, we could not find any other research into lasing at scales as small as ours—below 100nm," said Vitaliano. "Most scientists at the time believed that structures at that scale could not support lasing, but now we know it can using cavity quantum electrodynamics."
The nano-lasing property will initially be used in energy applications to produce self-generated light to prevent the build-up of industrial biofilm by killing the culprit organisms. Another potential application is nanoscale photonics. The researchers also claim that other quantum computing phenomena, for which ExQor has been granted U.S. patents, will enable novel spin-based, self-assembling nanoelectronic devices that could exceed the performance of planned nanoscale devices using traditional inorganic materials.
"Our aspiration is to enable bio-based quantum computing at the nanoscale [level] by using the same completely reversible processes that keep heat to a minimum in living things," said Vitaliano.
The researchers also are investigating intermolecular multiple quantum coherence and intermolecular zero quantum coherence, methods currently used to enhance the contrast of conventional magnetic resonance imaging, and as signposts for initiating and controlling quantum effects in the body.
- R. Colin Johnson