Currently the most viable treatments for cancer -- chemotherapy and radiation -- ravage patients’ bodies, nearly killing them in an effort to save their lives.  However, for lack of a better treatment these remain the best options for those fighting cancer.  Novel applications like targeted nanoparticles look promising in the long run, but they remain dependent on developing protein markers for cancer cells. Protein markers for one kind of cancer won't necessarily be the same of those of another type.

Researchers at Northwestern University have devised a promising alternative.  They have created an implantable micro-device which sucks up cells and then separates them based on size and shape. Cancer cells, which are differently shaped from healthy cells, are deposited in a reservoir, while healthy cells are returned to the tissue.

Researcher Bartosz Grzybowski, the paper's senior author, states, "We have demonstrated a principle that offers an unconventional way to fight metastasis, a very different approach from other methods, such as chemotherapy.  These are fundamental studies so the method needs to be optimized, but the idea has promise for a new approach to cancer therapy."

The team created a series of ratcheted channels -- essentially attached triangles -- which could guide cells in a single direction.  Cell repellents were applied to keep the cells away from certain parts, while cell adherents were patterned onto the substrate on surfaces they wanted the cells to travel along.  

The researchers then devised a means of filtering normal epithelial cells from cancerous cells from breast tissue.  The normal cells were long and thin with protrusions at the ends.  A special channel with spikes at 45 degree angles was created.  Normal cells could grab onto these spikes and pull themselves through.  Fat, round cancer cells, however, were blocked and traveled down a different channel to a central reservoir.

The technology could lead to minimally caustic implantable devices which could literally slowly suck out tumors and their metastasized cells, allowing for weaker chemotherapy to be used, or even perhaps to eliminate chemo altogether.  States Professor Grzybowski, "When implanted next to a tumor the particles would guide cancer cells, but not normal cells, inward to the reservoir, where they would be trapped.  The particles could also be part of the sutures used during surgical procedures."

The new research is reported in the journal Nature Physics.