Miniscule Magnetic Beads Improve Cancer Drug Delivery

Researchers are developing a treatment for cancer that attacks only cancerous cells, resulting in less harsh side effects than with radiation and chemotherapy.

The study, published in Scientific Reports, was conducted by researchers at the University of Copenhagen, who sought to find a way to transport cytotoxin through the blood stream to unload on cancerous cells.

In order to execute this concept, the researchers used tiny magnetic beads, a well-known approach in the medical research world, and placed them at the tumor site. Through this process, it allows the injected beads to travel through the bloodstream to reach the cancer site. The next step in the process was address the process of encapsulating the cytotoxin.

“We designed a ring-shaped sac of a biologically useful base material and using chemical processes we encapsulated the cytotoxin surrounding the beads,” said researcher Murillo Martins. “The coupling does not always happen, but using a separation process we can sort the beads from where the coupling with the sac did not succeed.”

In order to look inside the package containing the cytotoxin, researchers used the neutron-scattering facility at LANSCE and the synchrotron facility at Paul Scherrer Institute (PSI) in order to ensure that it was encapsulated in the ring-shaped package.

Next, researchers looked to find a way to get the package inside the cell. Since cells have a membrane that protects from foreign substances, researchers needed to activate the receptors that open the cell to let the substance in.

"Then I thought, why do breast cancer, lung cancer and ovarian cancer so often spread to the bones? Bones are composed of minerals like calcium phosphates,” Martins said. “Do cancer cells need these substances to grow? Can these substances be used as doorways to the cell? I decided to investigate this."

Researchers decided to coat the package containing cytotoxin with calcium phosphate. They performed experiments on breast, lung, and colon cancer cells as well as the healthy cells monocytes and fibroblasts.

The result of the study showed that the cancerous cells were able to absorb the packages. However, since cancer cells and healthy cells differ in metabolism, the 2 cells responded in different ways.

"We could see that the nanoparticles with the cytotoxin were absorbed by the cancer cells,” said Associate Professor at the Niels Bohr Institute, Heloisa Bordallo. “This caused the metabolism of the cancer cells to change and the cells showed signs that they were about to die. The healthy cells, meanwhile, do not show any evidences of absorbing the packages with the cytotoxin. This suggests that the method can be used to send cytotoxin around the body with reduced toxicity and could therefore be potentially safer for healthy cells."