Straight from science fiction, bacteria-based 'microrobots' could become a future cancer treatment

Scientists from the Max Planck Institute for Intelligent Systems in Germany have new research out that reads like the draft of the next science fiction series, suggesting Escherichia coli bacteria-based “microrobots” could be a future mechanism for treating cancer. 

The possible new mechanism takes a common therapeutic transportation device in bacteria and looks to supercharge it with specific biological attachments. Those attachments, highlighted in a study published Friday in Science Advances, include nanoliposomes packed with chemotherapeutic molecules and magnets to help guide the bacteria toward a potential tumor. 

To validate these microrobots, scientists first tested the ability of the magnets to guide the bacteria through the body and toward a tumor. Luckily, E. coli bacteria are already decent swimmers, so when attached with magnets and exposed to a magnetic field, the mobility of the bacteria was even more controlled. A number of different biological obstacle courses were constructed to test the bacteria's motion and the ability of the magnets to guide through different channels and dense solutions, reenacting potential pathways in the body. 

Once the microrobots build up around the tumor source, the drug-containing nanoliposomes are melted with a near infrared laser and the drugs are released. Areas with low pH are also able to trigger the nanoparticles to crack open. It’s like the cancer treatment equivalent of a Cadbury egg, except instead of a yellow creme filling, it’s an immune-system activating drug. Compared to a control, the biohybrids were shown to kill cancer cells in spheroids—3D cell aggregates that can mirror tissues or microtumors—and the death was further enhanced when triggered by the laser.

“This on-the-spot delivery would be minimally invasive for the patient, painless, bear minimal toxicity and the drugs would develop their effect where needed and not inside the entire body,” said Birgül Akolpoglu, lead author of the study's report. Metin Sitti, Ph.D., head of the physical intelligence department at the Max Planck Institute, said the potential of this treatment mechanism is “substantial.” Some past research on bacteria as a vehicle for cancer treatment has honed in on cloaking the bacteria from the body’s immune system so it could deliver treatment. 

“It is a new therapeutic approach not too far away from how we treat cancer today,” said Sitti. 

The researchers concluded that while genetically engineered bacteria have long been a difficult modality to translate in the clinic, biohybrids could be a more affordable approach with “advanced functionalities.”