June 24, 2011

Nanoparticles Fight Cancer

(Ivanhoe Newswire) "“ A novel discovery disguising nanoparticles as red blood cells allows them to invade the body without setting off an immune system response to deliver cancer-fighting drugs straight to the tumor.

The method involves collecting the membrane from a red blood cell and wrapping it around a biodegradable polymer nanoparticle stuffed with a cocktail of small molecule drugs.

"This is the first work that combines the natural cell membrane with a synthetic nanoparticle for drug delivery applications," Liangfang Zhan, a nanoengineering professor at the UC San Diego Jacobs School of Engineering and Moores UCSD Cancer Center, was quoted as saying. "This nanoparticle platform will have little risk of immune response."

Researchers have been working for years to develop a drug delivery system that mimics the body's natural behavior for more effective drug delivery.

Stealth nanoparticles are already used successfully in clinical cancer treatment to deliver chemotherapy drugs. They are wrapped in a synthetic material such as polyethylene glycol. Now, these newly disguised nanoparticles can now live in the body of mice for days instead of minutes or hours because of their red blood cell covering.

Using the body's own red blood cells marks a significant shift in focus and a major breakthrough in the field of personalized drug delivery research. Trying to mimic the most important properties of a red blood cell in a synthetic coating requires an in-depth biological understanding of how all the proteins and lipids function on the surface of a cell so that you know you are mimicking the right properties. Instead, Zhang's team took the entire surface membrane from an actual red blood cell and surrounded the nanoparticle with it.

Using nanoparticle to deliver drugs also reduces the hours it takes to slowly drip chemotherapy drug solutions through an I.V. to just a few minutes for a single injection of nanoparticle drugs. This significantly improves the patient's experience and compliance with the therapeutic plan. The breakthrough could lead to more personalized drug delivery wherein a small sample of patient's own blood could produce enough of the essential membrane to disguise the nanoparticle, reducing the risk of immune response to almost nothing.

Zhang said the next step is to develop an approach for large-scale manufacturing of these biomimetic nanoparticles for clinical use.

SOURCE: Proceedings of the National Academy of Sciences, published online June 20, 2011