Gel material spontaneously reforms in GI tract to boost nutrient delivery

17 Jul 2020 --- Rheologists are developing a hydrogel material that can degrade and spontaneously reform in the gastrointestinal (GI) tract, thus creating a more effective method for oral drug and nutrient delivery. New research investigates the covalent adaptable hydrogels (CAHs) with a pH environment that mimics the GI tract to simulate how the material would react over time if ingested.

“The majority of drugs and nutrients are absorbed into the body in the intestines, but to get there, they have to traverse the stomach, which is a very acidic, harsh environment. This can interfere with the active molecules in pharmaceuticals,” says Kelly Schultz, study co-author and Associate Professor of Chemical and Biomolecular Engineering at Lehigh University, US.

The CAHs are designed to release molecules as they lose polymer in the stomach but then re-gel on their own. This protects the molecules and allows them to stay active for targeted delivery in the intestines. Schultz expresses surprise at the unusual spontaneous re-gelation that CAHs exhibit. 

“Typically, gels won’t degrade and then reform without any added stimuli as these do. We’ve demonstrated the viability of CAHs as means of oral drug and nutrient delivery, and now we’re starting to work on molecular release studies and adding in other components to make the experiments more complex,” she details. 

Creating a “GI tract-on-a-chip”
The research was also carried out by chemical engineering PhD student Nan Wu, who repurposed a microfluidic device originally developed in Schultz’s lab for research involving fabric and home care products. This led to the creation of a “GI tract-on-a-chip,” which helps provide insight into the material’s pharmaceutical potential. This is by exchanging the fluid environment around the gel to mimic the pH environment of all the organs in the GI tract. 

Using microrheology, Wu collects microscopy data and measures how much particles within the gel wiggle. The experiments can last from a few hours to days, depending on the digestive organ she is replicating. She then tracks the particles using an algorithm that yields scientifically meaningful information on the properties of the material. 

Schultz’s research lab focuses on the characterization of colloidal and polymeric gel scaffolds and the development of new techniques to characterize these complex systems, which play important roles in fields such as health care and consumer products.  

“What we do in biomaterials is somewhat unique. There’s a lot of work on the cross-linking chemistry and actually developing these materials, and there’s a lot of animal research that implants and tests them, but there’s not that much work in the middle,” explains Schultz.

“A great deal of mystery lies between designing a material and understanding what’s going on when it’s working. We’re trying to find new ways that we can replicate what’s going on inside of an animal or a person and collect important measurements to connect the dots and inform further studies,” she concludes.

In other technological developments, researchers have developed chewing robots to measure bioavailability in gum. In April, industry highlighted that bioavailability can make or break ingredient formulations due to its crucial role in determining dosage effectiveness and quality. 

Edited by Katherine Durrell