Nanotechnology Guides Cancer Surgery And Kills Remaining Malignant Cells

Nanotechnology Guides Cancer Surgery And Kills Remaining Malignant Cells
A new system developed to improve cancer surgery uses a
nanoparticle called a dendrimer to carry a drug into cancer cells,
that can set the stage for improved surgery and also phototherapy.
(Graphic courtesy of Oregon State University)
Researchers have developed a new way to selectively insert compounds into cancer cells - a system that will help surgeons identify malignant tissues and then, in combination with phototherapy, kill any remaining cancer cells after a tumor is removed. It could be as simple as "if it glows, cut it out".
 
The findings, published in the journal Nanoscale, have shown remarkable success in laboratory animals. The concept should allow more accurate surgical removal of solid tumors at the same time it eradicates any remaining cancer cells. In laboratory tests, it completely prevented cancer recurrence after phototherapy.
 
Technology such as this, scientists said, may have a promising future in the identification and surgical removal of malignant tumors, as well as using near-infrared light therapies that can kill remaining cancer cells, both by mild heating of them and generating reactive oxygen species that can also kill them.
 
The work is based on the use of a known compound called naphthalocyanine, which has some unusual properties when exposed to near-infrared light. It can make a cell glow as a guide to surgeons; heat the cell to kill it; and produce reactive oxygen species that can also kill it. And by adjusting the intensity of the light, the action of the compound can be controlled and optimized to kill just the tumor and cancer cells. This research was done with ovarian cancer cells.
 
However, naphthalocyanine isn't water soluble and also tends to clump up, or aggregate, inside the body, in the process losing its ability to makes cells glow and generate reactive oxygen species. This also makes it difficult or impossible to find its way through the circulatory system and take up residence only in cancer cells.
 
The experts overcame these problems by use of a special water-soluble polymer, called a dendrimer, which allows the napthalocyanine to hide within a molecule that will attach specifically to cancer cells, and not healthy tissue. The dendrimer, an extremely tiny nanoparticle, takes advantage of certain physical characteristics that blood vessels leading to cancer cells have, but healthy ones do not. It will slip easily into a tumor but largely spare any healthy tissue.
 
Once in place, and exposed to the type of light needed, the cancer cells then will glow - creating a biological road map for a surgeon to follow in identifying what tissues to remove and what to leave. At the same time, a few minutes of this light exposure activate the naphthalocyanine to kill any remaining cells.
 
For many cancers, surgery is a first choice of treatment. This research may help make that surgery more precise, effective and thorough than it's been before.
 
Before attempting human clinical tests, the researchers hope to perfect the process and then test it on live dogs that have malignant tumors. The technique has already been shown successful in laboratory mice. The researchers noted that even as phototherapy was destroying their malignant tumors, the mice showed no apparent side effects and the animals lost no weight.
 
Originally posted by Oregon State University.