Bacteria-Based Microrobots Developed to Help Battle Cancer

Researchers have recently combined robotics with biology by equipping E. coli bacteria with artificial components to build biohybrid microrobots.

In the new study, the researchers from the Physical Intelligence Department at the Max Planck Institute for Intelligence Systems several nanoliposomes to every bacterium, Phys.org report specified.

On their external circle, the spherical-shaped carriers encompass a material, the ICG, green particles that melt when illuminated by close infrared light.

Further, towards the center, inside the aqueous core, the liposomes encapsulate water soluble chemotherapeutic drug molecules.

Magnetic Nanoparticles Attached to Bacterium

In their study published in Science Advances, the second component the study authors attached to the bacterium is magnetic nanoparticles.

When exposed to a magnetic field, the iron oxide particles function as an on-top booster to the already high motile microorganism.

In this manner, it is easier to control the swimming of the microbes, an improved design toward "an in vivo application," as the researchers specified in their study.

The rope that binds the liposomes and magnetic particles to the bacterium is a very stable and difficult-to-break streptavidin and biotin complex developed years before, and reported in an article published in the Nature journal comes in helpful when developing biohybrid microrobots.

E. Coli Bacteria

Essentially, E. coli bacteria are quick and versatile swimmers that can navigate through material that ranges from liquids to highly dense tissues.

That's not all, though, as they have highly advanced sensing abilities. Moreover, bacteria are drawn to chemical gradients like low levels of oxygen or high acidity, both predominant close to tumor tissue.

Cancer treatment through injection of bacteria in proximity is called "bacteria mediated tumor therapy." In connection to this, the microorganisms flow to where the tumor is located, grow there, and in this manner, activate patients' immune systems. The bacteria-mediated tumor therapy has been a treatment approach for more than 100 years.

Researchers have searched for ways to increase the microorganism's superpower for the past several years.

They equipped microbes with extra components to help fight the battle. Nevertheless, adding artificial components is not an easy task.

Complex chemical reactions are at play, and the viscosity rate of particles loaded into the microbes matters to prevent dilution.

Injecting Microrobots

Once the microrobots are built up at the desired point, which is the tumor spheroid, a near-infrared laser produces rays with temperatures of up to 55 degrees Celsius, stimulating a melting process of the liposome and the release of enclosed drugs.

An acidic or low pH environment causes the nanoliposomes to break open; hence the drugs are released close to humor automatically, as specified in the Max Planck Institute report.

"Imagine we would inject such microrobots" based on bacteria into the body of a patient, explained Birgül Akolpoglu, a Ph.D. student in the Physical Intelligence Department at MPI-IS.

Once enough microrobots surround the tumor, added Akolpoglu, they point a laser at the tissue, and that trigger releases the drug.

Related information about microrobots for drug delivery is shown on Chemical & Engineering News's YouTube video below:

Check out more news and information on Nanotechnology, and Medicine & Health in Science Times.