Cancer-killing hydrogel stays in place until the job is done

The cure for cancer might have been inside us all along – our own immune system. The trick is to give it a boost to find and destroy those rogue cells, and that's the focus of the field of immunotherapy. 

To that end, a new hydrogel has been developed that can be injected directly to the site of a tumor, where it stays to slowly release its payload of immunotherapy drugs for longer.

Cyclic dinucleotides (CDNs) are a type of drug sometimes used in immunotherapy treatments, usually administered through a simple injection. The problem is that the drugs end up being circulated throughout the body, which diminishes the concentration at the tumor site and results in them being flushed out of the body relatively quickly.

The new study, conducted by researchers at Rice University and the University of Texas Health Science Center (UTHealth), set out to keep the drugs in the right spot for longer.

Rather than being contained in a liquid solution, the CDNs are loaded onto self-assembling multidomain peptide (MDP) hydrogels. These start off in a liquid form for injection, but once inside the body they quickly turn semi-solid, before degrading slowly over time. In the process, they release their cancer-killing CDNs more gradually and precisely. The team calls their creation STINGel.

"The MDP hydrogel provides a unique environment for the release of CDN that other gels just can't match," says Hartgerink. "The CDN we used in this study is currently in clinical trials. We think that our STINGel approach has the potential to significantly broaden the scope of this powerful immunotherapy drug to a larger range of resistant cancers."