Scientists at Brown University have developed a new material that can release drugs only when pathogenic bacteria are around. When used as a bandage, the hydrogel could deliver medication on-demand when infection begins to take hold.
Overuse of antibiotics is one of the key drivers of drug resistance in bacteria. Delivering the right amount at the right time can help slow that process down, but it can be tricky to judge. So for the new study, the Brown researchers developed a smart material that only releases its drug payload when it detects bacteria.
The hydrogel is made up of a crosslinked network of polymers that can hold a cargo of nanoparticles, such as antibiotics, which would remain locked up tight. However, the material was designed so that these polymers would degrade when they encountered enzymes known as beta-lactamases, which are produced by many pathogenic bacteria. That in turn releases the nanoparticles.
“What’s interesting is that beta-lactamases are actually a major cause of antibiotic resistance as they destroy beta-lactam antibiotics, which are some of our most commonly prescribed antibiotics,” said Anita Shukla, lead researcher on the study. “But we’ve taken this bacterial defense mechanism and used it against the bacteria.”
The team tested the technique in lab dishes and in samples of pig skin, using fluorescent nanoparticles that could be clearly tracked as they were released. And sure enough, the hydrogels released their payloads in response to bacteria that produce beta-lactamases, while other bacterial enzymes didn’t degrade the structure. This shows that the technique can be selective for certain bacteria over others.
“We’ve developed a bacteria-triggered, smart drug-delivery system,” said Shukla. “Our hypothesis is that technologies like this, which reduce the amount of drug that’s required for effective treatment, can also reduce both side effects and the potential for resistance.”
Similar controlled-release hydrogels have been tested as a way to fight cancer, by releasing anti-cancer drugs in response to the acidity and temperatures of a tumor microenvironment. In this case, the team says that the new hydrogel could be used as a wound dressing that immediately and effectively releases antibiotics when an infection begins to emerge.
The research was published in the journal ACS Applied Materials and Interfaces.
Source: Brown University
