Stopping cancer cells from growing in the body is one of the biggest challenges of modern medicine. But now, a group of scientists from the Max Planck Institute for Intelligent Systems says they have come up with an advanced therapy that uses bacteria to fight tumors that spread cancer. As part of the proposed treatment, bacteria-based microrobots that are guided by magnets would carry the medicine.
The drugs are put directly into the tumors by the microrobots, killing the cancer cells in a painless and effective way. “This on-the-spot delivery would be minimally invasive for the patient, painless, and have low toxicity,” said Yunus Alapan, a co-author of the study. “The drugs would work where they need to, not in the whole body.”
During their study, the researchers were able to attach nanoliposomes and magnetic nanoparticles to about 86 E. coli bacteria. Nanoliposomes are spherical lipid vesicles that are used to store drugs inside them. Common bacteria were turned into a small army of bacterial biohybrid microrobots by these special attachments. Each modified E. coli has many nanoliposomes attached to it. These nanoliposomes are actually vesicles that are filled with chemotherapeutic drug molecules. When they come in contact with infrared rays, it’s easy to peel off their outer layer. On the other hand, the bacteria’s magnetic particles (iron oxide) are used to control how they move around inside the human body.
Since E. coli is a microbe that moves around a lot, researchers put it in a magnetic field. The iron oxide particles and the bacteria they were attached to moved in the same direction as the magnetic field. Also, the researchers used streptavidin-biotin complexes, which are the most powerful biomolecule-binding agents and are often used to find new drug targets, to connect the bacteria to the magnetic particles and nanoliposomes. Streptavidin-biotin complexes are very stable, and they tie the attachments to the bacteria like a rope that can’t be broken. Birgül Akolpoglu, who led the study and explained the process further, said, “Imagine we would inject these bacteria-based microrobots into the body of a cancer patient. With the help of a magnet, we could guide the particles right to the tumor. Once there are enough microrobots around the tumor, a laser is pointed at the tissue, which causes the drug to be released. Now, not only is the immune system woken up, but the extra drugs help kill the tumor as well.
The researchers say that biohybrid microrobots can be used to give chemotherapeutic drugs “on the spot” without causing pain or infection inside the patient’s body. Also, if more research and development is done, it could become one of the best ways to treat cancer in the future. Based on a method called bacteria-mediated therapy, the biohybrid microrobots could be used to treat cancer (using bacteria to deliver drugs or release enzymes in the human body at desired locations). Surprisingly, this isn’t a new way to treat a disease, but it’s been hard to do. Scientists have tried many times to put anti-cancer drugs into microorganisms.
But most of them failed because using this strategy to treat someone successfully requires a perfect mix of different techniques. This is where Birgül Akolpoglu and her team were able to get ahead of everyone else. They used materials that made common bacteria work better and turned them into very effective nanomachines for delivering drugs. For example, the nanoliposomes that were attached to the bacteria were made of special containers called “green particles” that were good at storing the cancer drugs. Only when they came in contact with infrared radiation did these particles let out the drug (a laser beam). Plus, there was no way for therapeutic molecules and natural bacterial secretions to interact with each other.
Researchers used the magnetic properties of particles made of ferrous oxide to help E. coli move around better. So, by combining robotics, physics, and biology, the researchers at the Max Planck Institute for Intelligent Systems were able to come up with the right parts to solve the problems that come with using bacteria to treat cancer.