Shape-shifting agent kills harmful bacteria in stomach: study

A new shape-shifting polymer can target and kill Helicobacter pylori bacteria in the stomach without killing helpful bacteria, researchers at the University of Illinois (UI) in collaboration with fellow colleagues in China and at Vanderbilt University found.

The findings have been newly published in the Proceedings of the National Academy of Sciences.

This may prove a new treatment to billions of people who contract H. pylori infections worldwide.

UI researchers previously developed short protein chains that twist into a helical spiral, giving them a stiff, rod-like structure that can punch holes through bacterial membranes, a method of killing that bacteria have little ability to develop resistance to. With a few simple alterations to the side chains that branch out from the polymer backbone, the researchers created a shape-shifting version of the hole-punching agent.

The antimicrobial agent morphs into a bacterial hole-puncher in the stomach's acidic environment, allowing targeted killing of H. pylori, and reverts to an amorphous, inactive structure when it reaches the higher pH environment of the small intestine.

"This is a very simple solution to this disease," said Jianjun Cheng, a UI professor of materials science and engineering. "These materials become therapeutically effective in the stomach, but once they move to the small intestine, where you have a lot of good bacteria and the pH is neutral or slightly basic, the materials quickly lose their rigid structures. Then they are excreted from the body."

The researchers tested the drug on mice with H. pylori infections from several different cell lines, and found that the drug was effective against the H. pylori while maintaining populations of healthy gut bacteria.

"Fifty percent of the world population will have H. pylori infections in their lifetime," said Cheng. "Our conformation-switchable polypeptide is the only therapy reported so far that can kill this bacteria at a specific pH range."

The researchers are performing tests in large animal models as the next step toward human studies. They have obtained a patent and are working toward commercializing the agent as well.