Nano robot destroys bacteria around the wound

Samuel Sánchez, a scientist at the Catalonia Institute of Bioengineering in Barcelona, ​​thinks that nanorobots can deliver cancer drugs or antibiotics through the body's mucus. He used spherical silica beads to act as the chassis. On the surface of the seed there are special proteins that help propel the seed through the liquid like a small motor. In the study, published in the journal ACS Nano, Sánchez collaborated with antibiotic researchers. They placed experimental antibiotics on silica nanorobots, including bee venom extracts, to treat wounds in mice. The nano robot dropped at one end of the infected wound moves through the skin to treat the entire area. This is the first report of nanorobots killing bacteria in animals.

Simulate a robot swimming around the wound.

"We noticed that the entire wound was slowly healing. The machine was able to move around the wound and clean up the infection," said César de la Fuente, a bioengineer at the University of Pennsylvania who led the project with with Sánchez, said.

Sánchez designed a nanorobot that delivers drugs to an infection inside mucus like sebum. According to him, places with high oiliness or low diffusion are the places where the robot needs to be in motion.

Sánchez's team created two robot sizes out of silica silicon dioxide: nanoparticles and slightly larger microparticles. They used a protein called urease to propel the particles. Urea is an enzyme that turns urea in the body into ammonia and carbon dioxide. Like a car engine, that enzyme turns chemical reactions into mechanical energy. Urea is the fuel. Sánchez shares the secret of covering the robot with asymmetrically arranged motors. These allow the robot to move chaotically from the starting point instead of running around.

De la Fuente's lab offers experimental antibiotics including LL-37, a long natural antibiotic peptide, and K7-Pol, a shorter synthetic peptide derived from bee venom. Both disintegrate bacterial cell membranes, rendering them inactive. In the laboratory, K7-Pol is effective against parasites and cancer cells.

Next, the team demonstrated that the robot could swim. In a test tube containing urea, the robot reached speeds of up to 4 micrometers per second. Then, some mice were injected with the drug-delivering robot LL-37 and others with the drug-delivering robot K7-Pol. Wounds with only antibiotics without robots only heal locally. The number of bacteria is reduced by 100 - 1,000 times but only in the place where the medicine is placed. The rest of the wound continued to behave as if it had not been treated. But antibiotic-carrying nanorobots not only treat the entire wound, but also reduce the number of bacteria 100 to 1,000 times, to a level that the immune system can handle.