Singapore scientists design hydrogels that react to pH, temperature

When you read about a "smart" drug-delivery technology, what makes it so smart is its ability to automatically react to changing conditions once it's cruising inside the body. It's the entire basis for new anti-cancer drugs being developed that can avoid harming healthy cells and target only cancer cells. Hydrogels, too, can be "programmed" to react to pH levels inside the body. At the Institute of Materials Research and Engineering (IMRE) in Singapore, scientists are working on hydrogels that can change their density in reaction to pH levels. This means that one hydrogel dose could be loaded with different drugs that could be released at different densities at different pH levels. If you're talking about an ointment on the skin, it can react to sweat. At thinner densities, inside the body, it can tell if it's in the oral cavity vs. the stomach--or in a healthy or cancerous cell.

"As far as we know, we are the first ones to have this degree of control in a hydrogel system," Liu Ye, the IMRE scientist who heads the research, said in a release. "It is difficult to control the cross-linking degree, or how viscous the hydrogel can get in other methods once the reactions have started."

And it's not only pH changes that IMRE researchers are working on. Another innovation are hydrogels that react to temperature change. Scientists are putting together blocks of copolymers that react in different ways to temperature, and are stacking them like LEGOs. "Such a polymer allows us to create new smart controlled release tools for medicines, where multiple drugs could be incorporated into the polymer and released stepwise at different locations where the temperature is different," Li Jun, an IMRE senior scientist, said in a news release.

- take a look at the release from IMRE