Flash NanoPrecipitation

Flash NanoPrecipitation is a new clever way to create nanoparticles for drug delivery, etc:

In NanoPrecipitation, two streams of liquid are directed toward one another in a confined area. The first stream consists of an organic solvent that contains the medicines and imaging agents, as well as long-chain molecules called polymers. The polymer chain is like a necklace of pearls with half of the pearls being hydrophopic and the other half being hydrophilic. The second stream of liquid contains pure water.
When the streams collide, the hydrophobic medicines, metal imaging agents and polymers precipitate out of solution in an attempt to avoid the water molecules. The polymers immediately self-assemble onto the drug and imaging agent cluster to form a coating with the hydrophobic portion attached to the nanoparticle core and the hydrophilic portion stretching out into the water. By carefully adjusting the concentrations of the substances, as well as the mixing speed, the researchers are able to control the sizes of the nanoparticles.
The stretched hydrophilic polymer layer keeps the particles from clumping together and prevents recognition by the immune system so that the particles can circulate through the bloodstream. The hydrophobic interior of the particles ensures that they are not immediately degraded by watery environments, though water molecules will, over time, break the particles apart, dispersing the medicine.
Ideally, the particles would persist for six to 16 hours after they were administered intravenously, Prud’homme said, which would theoretically allow enough time for the potent packages to slip into the solid tumor cells they encountered throughout the body.
In the lab, this is precisely the amount of time it takes for water molecules to work their way into the centers of the nanoparticles and degrade them. The team made their particles even more resistant to early degradation by attaching hydrophobic substances, including vitamin E, to the medicines and imaging agents before incorporating them into the particles. Further studies of the controlled release technique currently are under way.
Prud’homme’s technique [Robert Prud’homme is a Princeton chemical engineering professor and the director of a National Science Foundation-funded team of researchers at Princeton –ed.] is essentially the opposite of previous techniques for improving drug delivery, which is to attach molecules to drugs to make them more water soluble. “Our advance is to use this technique and turn it around so the drugs stay inside our particles until we want them to leave,” he said.
Beyond using size alone to target cancer cells, the team is working with Princeton mechanical and aerospace engineering professor Wole Soboyejo to create nanoparticles that have specific linking molecules on their surfaces. These particles will bond to substances that are more prevalent in cancer cells than normal ones.

Press release: Little lifesavers: Nanoparticles improve delivery of medicines and diagnostics …