http://www.popsci.com/popsci/science/d1e17ec2d6221110vgnvcm1000004eecbccdrcrd/3.html

Perfect Plumbing
Scientists invent super-smooth, super-small pipes that could ferry
medicine into the body

Scientists at the University of Kentucky have built tiny pipes that
move water 10,000 times as fast as the conventional laws of fluid
flow allow, mimicking for the first time the seamless way fluids
progress through our cells. They've also found a way to control which
molecules can pass through the pipes, a discovery that could yield
safer, more efficient skin patches to deliver medicine into the body.
The pipes are made of carbon nanotubes, thin sheets of graphite
rolled into cylinders just seven billionths of a meter in diameter.
The scientists poured a polymer between them to create a fine
membrane that can embed 65 billion pipes per square inch.

Lead researcher Bruce Hinds attributes the tremendous speed of the
water flow (3.3 feet a second) to the nearly friction-free carbon
nanotube walls. To keep out unwanted molecules, Hinds placed chemical
receptors at the entrances to each tube, so that only those proteins
that match the receptors are allowed passage.-Gregory Mone