14 February 2012
Heating water inside carbon nanotubes until they explode could deliver drugs precisely, say chemists
Carbon nanotubes offer a number of exotic options for therapies. For example, tubes filled with drugs and sealed with biodegradable caps, could work their way inside cells where they deliver their load.
But the worry is that such a scheme may not target the drugs well enough if the caps degrade too quickly or too slowly.
So Vitaly Chaban and Oleg Prezhdo at the University of Rochester in New York state have a suggestion. Their idea is to fill the tubes with a mixture of drugs and water molecules and seal them with a secure cap.
Inside the body, the tubes enter various types of cell. But a treatment would involve illuminating only the cells of interest with an infrared laser which heats the tubes and boils the water they contain. The resulting increase in pressure bursts the cap and forces the water and drug molecules into the cell, like a grenade bursting.
These guys have carried out a molecular dynamics simulation to study how such a process might work. They say confinement in a nanotube substantially changes the boiling point of water and that just a small increase in temperature can boil the water and create pressures equivalent to hundreds of atmospheres.
That could be another tool in the rapidly expanding armoury of drug delivery mechanisms. But Chaban and Prezhdo will need to answer some additional questions about the safety of this process.
One obvious potential problem is that the explosive destruction of carbon nanotubes could damage the molecular machinery inside cells. That could cause more problems than it solves.
The advantage, though, is that the drug is delivered only at the spot where it is required at the instant it is needed.
It’s an idea that could be relatively easily tested and may turn out to be hugely useful.
Ref: arxiv.org/abs/1202.1328: Water Boiling inside Carbon Nanotubes: Towards Efficient Drug Release