Drug-resistant bacteria present a couple types of problems--they don’t die when attacked with typical antibiotics, and they form slimy, hard-to-remove colonies called biofilms, meaning they literally stick around after you’ve tried to wash them off. New treatments to prevent their spread have to take a different approach from other antimicrobial products. Researchers at IBM have a new idea, and they say it could work in hospitals, countertops and on your skin.
The new antimicrobial hydrogel, made of 90 percent water, gloops together spontaneously when warmed to body temperature. It can bust through biofilms and kill a whole host of bacterial types, from small bugs like E. coli to large bugs like methicillin-resistant Staphylococcus aureus. The hydrogel is comprised of specially designed polymers, which are biodegradable and positively charged. When mixed with water and warmed up, the polymers self-assemble into chains, and the result is a thick gel.
The research team, led by Yi-Yan Yang at the Singapore-based Institute of Bioengineering and Nanotechnology, says the gel can be incorporated into creams, thin-film coatings for medical instruments, wound treatments, and plenty of other uses.Their key breakthrough is the way the material hunts down and kills its quarry. Rather than interfering with DNA or selectively binding to a bacterial cell wall, like antibiotics do, the polymers grab on to the cell wall and rip it open, letting the contents leak out. This is possible because of their positive charge--matching the negatively charged cell wall of a microbe--and their hydrophobicity, or avoidance of water. Bacteria stand no chance, and they can’t evolve resistance to this method of attack the way they could evolve resistance to the proteins found in drugs. It’s a physical attack.
Right now, the researchers don’t even know how the biofilm disruption works--they just know it does, said James Hedrick, an advanced organic materials scientist at IBM Research. “It is clearly interacting in a favorable way that allows this stuff to be eradicated,” he said. “It can remove this extracellular matrix of proteins, rip them up, and eradicate the microbes below. We found this to be very exciting.”
The team first came up with this concoction a couple years ago, but back then the treatment involved biodegradable nanoparticles that could only target large bacteria, like MRSA. By refining their methods and crafting a hydrogel instead, the team was able to broaden the range of microbes it can tackle.
IBM is in talks with several possible companies to sell the hydrogel as a new antimicrobial product, Hedrick said. Meanwhile, he and the other researchers are setting their sights on another target. “Now that we understand the mode of action, we are starting to move in and think about viruses,” he said. “That is high on our priority list--we’re looking at tuberculosis, dengue fever, things that there aren’t a lot of solutions for. Those are areas we are looking to move towards.”
A paper describing the new hydrogel appears in the new issue of Angewandte Chemie.