Sperm power could drive nano-scale robots

Scientists are examining whether they can harness the energydriving human sperm to propel nano-scale robots or deliver medicine to targeted sites in the body.

By deconstructing the stages in the biological pathway sperm cellsuse to generate their relentless energy, researchers at the Cornell University College of Veterinary Medicine in the United States hope to recreate that process in an artificial device.

Such a device, they say, could be used to help build a delivery system for chemotherapy drugs or antibiotics that would decrease side-effects by allowing medicines to travel directly to the sites where they are needed, and not peripheral areas of the body.

"Our idea is not the final product but rather an energy-delivery system," said the study's senior author Alex Travis, Cornell assistant professor of reproductive biology at the College of Veterinary Medicine's Baker Institute for Animal Health.

Powerful, albeit microscopic, sperm cells use a kind of dual-engine system to generate their energy. Organelles in a sperm cell's midsection provide one part of its battery power, while a second process occurring in the long, spindly tail gives it an additional boost.

It is during this second process that ATP-generating enzymes bind to the sheath of a spermatozoa's tail to give itthat extrazip.

Researchers haveattached three of the 10 enzymes needed to create this glycolytic pathway to nickel ions on a tiny manufactured chip.Their goal now is to attachthe remaining seven enzymes, in effect creating nano-robots fuelled by sperm power.

"As a proof of principle that this kind of strategy could work, we've shown that the first two enzymes could be attached to the same chip and act in series," added Chinatsu Mukai, a postdoctoral associate in Travis's lab and a co-author.

Researchers presented their findings atthe American Society for Cell Biology's 47th annual meeting in Washington, D.C., on Dec. 3.

Their next step isto attractfunding in order to finish attaching the remaining enzymes.

"We have a provisional patent, so if a company shows interest, we could also work something out with them," said Travis.