by: Levi Beckerson
CampusFind.com
It's looking pretty bad for cancer these days thanks to our friend nanotechnology.
Last week, DailyTech covered a new type of nanoparticle intended for use as a cancer therapy. The polymeric particle would carry the common chemotherapy drug doxorubicin to the site of metastasizing tumors, where it would release the chemical, destroying the tumor's cells while leaving healthy cells largely unaffected. The treatment, designed by UCSD medical scientists, works very well on the intended target, but saw little to no results in affecting primary tumors.
Researchers at Washington University, led by Karen Wooley, Ph. D., are developing a similar delivery vehicle to ferry doxorubicin to tumors in the brains of children, where heavy chemotherapy can irreparably damage the developing bio-computer. Though her group uses the same family of polymeric nanoparticles, the delivery and effectiveness differs from UCSD's treatment.
Some of the properties of the nanoparticle important to Wooley's group are its carrying capacity and the way it releases the cancer toxin into the body. Most polymeric based nanoparticles have at best a three to four percent drug capacity. Wooley's group's particles boast an up to 19 percent loading, five times the typical delivery vehicle's capacity. While the large increase in toxin is beneficial, not all of the toxin in these particles will be released.
Another difference is the rate at which the drug is released into the patient. Most cancer-targeting nano and macroparticles verily explode a cancer cell in one way or another. The WU group's particles are designed to release the toxin more slowly over time. The group is working to tune these properties further, allowing a tailored particle delivery vehicle.
One area yet to be refined by Wooley's team is the actual targeting method for binding the particles to cancer cells. The typical approach has been to use a ligand structure targeting protein expressions unique to cancerous cells. While this is under development, another method, exploiting the “enhanced permeability and retention effect” of tumors would rely on passive diffusion to absorb the particles into a tumor where the doxorubicin could be released directly into the mass.
