Polymer Nanoparticle Kills Tumors

Jan 12, 2006

Photodynamic therapy (PDT), which uses a light-sensitive chemical known as a photosensitizer to produce cell-killing “reactive oxygen,” has become an important option for the treatment of esophageal cancer and non-small cell lung cancer. Current photosensitizers, however, produce significant side effects, including sensitivity to the sun, that limits their wider use in treating cancer.

In an attempt to both eliminate those side effects and increase the anticancer activity of photosensitizers, a multi-institutional research team led by Ralph Weissleder, M.D., co-director of the MIT-Harvard Center of Cancer Nanotechnology Excellence, has developed a polymer nanoparticle to ferry photosensitizers into cancer cells, where they can then unleash their potent cell-killing effects. The investigators report their work in the journal Nano Letters.

Dr. Weissleder and his colleagues created nanoparticles from a biodegradable polymer known as poly(lactic-co-glycolic acid), and used these nanoparticles to encapsulate a photosensitizer designed to aggregate, or clump together, within the nanoparticle. Such aggregation prevents the photosensitizer molecules from being activated by light, rendering them non-toxic while circulating in the bloodstream. But once the nanoparticles are taken up by cancer cells, they fall apart and release the photosensitizer molecules, which then disaggregate. As a result, the photosensitizers become active once more and can kill cancer cells when irradiated with light. When stored in the dark at room temperature, the nanoparticle-photosensitizer formulation is stable for 6 to 12 months.

Experiments using cancer cells grown in culture dishes showed conclusively that the nanoparticle-photosensitizer formulation had little toxicity to cells unless taken up within the cells. The investigators also conducted tests in which they injected this formulation into tumor-bearing mice and then administered light therapy 24 hours later. This experiment confirmed that the nanoparticle-borne photosensitizer accumulated in tumor cells and was capable of killing those cells when exposed to light.

This work, funded in part by the National Cancer Institute, is detailed in a paper titled, “Polymeric nanoparticle preparation that eradicates tumors.” Investigators from the University of Connecticut and the University of Central Florida also participated in this study. An abstract is available through PubMed.

Source: National Cancer Institute

Explore further: Innovative strategy to facilitate organ repair

add to favorites email to friend print save as pdf

Related Stories

Physicists create new nanoparticle for cancer therapy

2 hours ago

A University of Texas at Arlington physicist working to create a luminescent nanoparticle to use in security-related radiation detection may have instead happened upon an advance in photodynamic cancer therapy.

Taking the fight into the enemy's territory

May 29, 2013

(Phys.org) —German researchers have developed a scheme for the preparation of nanoparticles that offer a highly versatile system for targeted drug delivery directly into diverse types of tumor cells.

Photo-immunotherapy boosts nanoparticle delivery to tumors

Feb 22, 2013

(Phys.org)—One of the main reasons that nanoparticles can boost the effectiveness of an anticancer drug while decreasing its toxicity is that they are able to accumulate at cancerous sites in the body through the abnormally ...

Recommended for you

Innovative strategy to facilitate organ repair

Apr 18, 2014

A significant breakthrough could revolutionize surgical practice and regenerative medicine. A team led by Ludwik Leibler from the Laboratoire Matière Molle et Chimie (CNRS/ESPCI Paris Tech) and Didier Letourneur ...

'Exotic' material is like a switch when super thin

Apr 18, 2014

(Phys.org) —Ever-shrinking electronic devices could get down to atomic dimensions with the help of transition metal oxides, a class of materials that seems to have it all: superconductivity, magnetoresistance ...

Thinnest feasible nano-membrane produced

Apr 17, 2014

A new nano-membrane made out of the 'super material' graphene is extremely light and breathable. Not only can this open the door to a new generation of functional waterproof clothing, but also to ultra-rapid filtration. The ...

User comments : 0

More news stories

'Exotic' material is like a switch when super thin

(Phys.org) —Ever-shrinking electronic devices could get down to atomic dimensions with the help of transition metal oxides, a class of materials that seems to have it all: superconductivity, magnetoresistance ...

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.