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.

Inflammatory bowel disease (IBD) is an ongoing or chronic health problem that causes inflammation and swelling in the digestive tract. The irritation causes bleeding sores called ulcers to form along the digestive tract. This, in turn, can cause cramps, abdominal pain, and severe bloody diarrhea.

There are two main types of inflammatory bowel disease: ulcerative colitis (UC) and Crohn's disease (CD). The diseases are very similar. Doctors often have a hard time figuring out which type of IBD a person has.

The main difference between UC and CD is the area of the digestive tract they affect. CD can occur along the entire digestive tract and spread deep into the bowel wall. In contrast, UC usually only affects the top layer of the large intestine (colon) and rectum.

Symptoms of IBD

Medicine can control the symptoms of IBD in most women. But for people who have severe IBD, surgery is sometimes needed. Over the course of a person's life, the symptoms of IBD often come and go. With close monitoring and medicines, most people with IBD lead full and active lives.

To make it to the intestine, though, probiotics must first pass through the stomach, a hostile acidic environment that can kill these beneficial bacteria. Now, scientists report in ACS Sustainable Chemistry & Engineering the development of a protective gel sphere that may offer probiotics a safer route.

Probiotics are living organisms and have beneficial effects when they colonize the body, assuming they can stay alive long enough to do so. 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, like fruit trapped in a gelatin mold.

Alginate is not the ideal treatment ingredient though, because it can break down easily. To beef up the stability of alginate, Hu Tang, Fenghong Huang and colleagues wanted to see whether adding cellulose, a fibrous biocompatible polymer with excellent stability, could help.

To make the probiotic shield, the researchers mixed dilute solutions of cellulose and alginate, then added the "friendly" bacteria to that mixture. The final step was to drip this brew into a solution of calcium chloride.

The researchers dropped the probiotic globs into an acidic stomach-like environment and found that the gel held onto the bacteria. By contrast, in a simulated intestine, which has a more neutral pH, the bacteria gel swelled, releasing the probiotics. They say that the next step is to test the encapsulation system in animals.