We’ve deployed nanoparticles (that is, particles measured in billionths of a meter) in the war on cancer for awhile now. For example, Abraxane packages the breast-cancer drug Taxol with albumin, a tiny blood protein that improves drug delivery and reduces side-effects.
Now, scientists have begun testing a new generation of nanoparticles that attack malignancies in a different way. By focusing energy from external sources, the new nanoparticles destroy cancers physically rather than chemically.
Jennifer West at Rice University for example, has developed gold- and silicon-based nanoparticles that absorb infra-red light and then heat up. If we can deliver these nuggets exclusively to the site of a cancer and turn on the juice, the tumor cooks while normal tissue remains unharmed.
It turns out this is quite possible because the pores of tumor capillaries are many nanometers larger than normal. It’s just a matter of creating nanoparticles exactly the right size to exploit the difference.
West’s nanoparticles have proven effective and safe in mice and dogs. Her team has begun testing them in humans with head and neck cancer.
Other teams are deploying nanoparticles of their own. The privately held German company MagForce Nanotechnologies for example, injects iron-containing particles directly into tumors and heats them with magnetic fields.
And the Taxol/albumin vehicle is only the first of what will likely be many cancer-fighting, drug-based nanoparticles. CytImmune Sciences of Rockville, Maryland has initiated a study of another gold nanoparticle that delivers tumor necrosis factor, while Calando Pharmaceuticals of Pasadena, California has enclosed camptothecin in a protective nanoparticle made of sugar.
The particular nanoparticles mentioned here may or may not prove effective, but those leaky tumor capillaries provide an opening big enough to drive a truck through.