Multilayered microvehicles lure, trap and kill super bacteria
With the rise of antibiotic-resistant bacteria, drugs alone aren’t enough to keep serious infections at bay. Creative new treatments are sorely needed, and now researchers at the University of California San Diego (UCSD) have developed a concept that’s just crazy enough to work – self-propelling “microvehicles” that lure bacteria into a trap, then kill them.
The microvehicles, as the team calls them, are essentially nanoparticles made up of several layers that all play vital roles in the process. The core of the microbead is made of magnesium metal, which is coated in several polymer layers. At one end is a hole that exposes this core to the outside environment.
The idea is that when these beads enter an acidic environment – such as acid in the gastric tract – the magnesium reacts to it, producing hydrogen bubbles. This creates a jet that pushes the vehicle in the opposite direction, in a mechanism we’ve previously seen used in microbots like the Janus particles.
This will lodge the vehicle in the stomach lining, and once the magnesium has finished dissolving it leaves the particle hollow. That exposes the next polymer layer, which then begins to dissolve. This layer contains serine, an amino acid that bacteria like E. coli regard as a food signal, so it effectively lures the bugs into the shell.
Once the bacteria gather inside the particle, the next layer brings down the final curtain. As this one dissolves it releases silver ions, which are known to be toxic to many microbes.
In tests, the researchers observed that the microparticles did encourage E. coli to move into the empty sphere, where they can then be effectively killed.
The team says that this method could be particularly useful for controlling infections in the gut, delivering more killing power where it’s needed. After all, most drugs tend to dilute in body fluids before they find their target. The concept could also be used for decontamination in other areas, such as ensuring the safety of food, or cleaning up the environment.
The research was published in the journal Angewandte Chemie.