"Smart" bio-nanotubes have been developed that could be used for drug or gene delivery.
According to a news release from the University of California, Santa Barbara:
The nanotubes are "smart" because in the future they could be designed to encapsulate and then open up to deliver a drug or gene in a particular location in the body. The scientists found that by manipulating the electrical charges of lipid bilayer membranes and microtubules from cells, they could create open or closed bio-nanotubes, or nanoscale capsules.
Researchers including materials scientist Cyrus R. Safinya and biochemist Leslie Wilson used microtubules purified from the brain tissue of a cow for their experiments. As the news release describes:
Microtubules are nanometer-scale hollow cylinders derived from the cell cytoskeleton. In an organism, microtubules and their assembled structures are critical components in a broad range of cell functions—from providing tracks for the transport of cargo to forming the spindle structure in cell division. Their functions include the transport of neurotransmitter precursors in neurons...
[The researchers use] the example of water beading up or coating a car, depending on whether or not the car has been waxed. Likewise the lipid will either bead up on the surface of the microtubule, or flatten out and coat the whole cylindrical surface of the microtubule, depending on the charge.
The inner space of the nanotubes in the experiments measures about 16 nanometers in diameter while the whole capsule is about 40 nanometers in diameter.
Drugs that could be delivered with the nanotubes include Taxol. The researchers are already using Taxol in their experiments to stabilize and lengthen the lipid-protein nanotubes.