Microbial wearing of "vests" can better treat gastrointestinal diseases

Drinking yogurt will drink probiotics into the stomach, these probiotics are actually "living biological drugs", which is conducive to our gastrointestinal peristalsis. Scientists have tried to develop "living biotherapies" to deal with certain gastrointestinal disorders in the human body, but because many probiotics are extremely sensitive to oxygen, it has become difficult to make, store, and transport them. According to a study recently published in the Journal of the American Chemical Society, researchers at the Massachusetts Institute of Technology in the United States can help bacteria survive the manufacturing process by covering them with a coating material made of metal ions and polyphenolic organic compounds.

Most gastrointestinal microbes are anaerobic, and some can tolerate trace amounts of oxygen, but for others, oxygen is deadly. Testing whether they can treat human diseases is difficult because the bacteria need to be freeze-dried and made into capsules before they can be used for treatment.

This time, the researchers decided to try to put on a protective coating "vest" for anaerobic bacteria, which they tested on a type of E. coli and Bacteroides polyforme. Bacteroides polyforme is the best carbohydrate-degrading bacteria, mostly found in the gut microbiome of healthy people, and is very sensitive to oxygen.

Studies have found that when polyphenols and metal ions in the coating are put into solution, they form a two-dimensional, grid-like film. For the study, the researchers used food-grade iron, as well as three polyphenols classified by the U.S. Food and Drug Administration (FDA) as GRAS (generally recognized as safe): gallic acid, tannic acid, and epigallocatechin. Several of these polyphenolic organic compounds are found in tea and other plant products.

If bacteria are also added to the solution, the mesh-like membrane self-assembles a coating on individual bacterial cells. This coating protects bacteria during freeze drying and manufacturing. Studies have shown that the cells covered by the coating are healthy and able to perform normal cellular activity, but their growth is temporarily inhibited. When exposed to an acidic environment such as gastric juice, the coating breaks down and releases bacteria.

The researchers say the coating protects almost all microbes. In addition to treating human gastrointestinal diseases, bacteria with this protective coating can also be used in the agricultural sector, for example to help improve the stress resistance of crops. In addition, it can be used to protect microorganisms used as vaccines.

(Intern reporter Zhang Jiaxin)

Source: Science and Technology Daily