Protecting Probiotic Bacteria From The Stomach

Scientists in China have encapsulated probiotics in a cellulose-alginate gel to allow the bacteria to withstand acidic conditions in the stomach.

AsianScientist (Oct. 9, 2018) – A team of scientists in China has developed a protective gel sphere to help probiotics survive the acidic conditions in the stomach and reach the small intestine. Their findings are published in ACS Sustainable Chemistry & Engineering.

The small intestine is a hotbed of microbial activity and a target of probiotic treatments for diarrhea, inflammatory bowel disease and irritable bowel syndrome, among other conditions. Probiotic treatments are packed with bacteria, but once swallowed, their numbers are dramatically diminished by the stomach’s acidity, lowering the chances of therapeutic effect.

In previous work, scientists have attempted to protect probiotics in the stomach by encapsulating them in alginate, a gummy polymer produced by algae. However, alginate can also be broken down easily.

To increase the stability of alginate, Professors Tang Hu and Huang Fenghong at the Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, China, added cellulose—a fibrous biocompatible polymer with excellent stability—to alginate.

The researchers first mixed probiotics into dilute solutions of cellulose and alginate. This was followed by dripping the mixture into a calcium chloride solution, which resulted in the formation of gel droplets. When these probiotic-laden gel droplets were immersed in an acidic stomach-like environment, the researchers observed that the gel did not dissolve and the probiotic bacteria remained encapsulated.

In contrast, when the scientists immersed the probiotics-containing gel droplets in a solution that simulated the intestine, which has a more neutral pH, the gel swelled and released the probiotics. Going forward, the researchers intend to evaluate whether their method of protecting probiotics works in animal models.

The article can be found at: Zhang et al. (2018) A pH-Responsive Gel Macrosphere Based on Sodium Alginate and Cellulose Nanofiber for Potential Intestinal Delivery of Probiotics.


Source: American Chemical Society; Photo: Shutterstock.
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