Gels are a promising method of drug delivery because they are moldable and can release their payload over a specified time period, and researchers have now created a "self-healing" version that can be injected with a syringe instead of surgically implanted.

The newly designed gel could also carry two drugs at once, which could be useful in the treatment of serious illnesses such as cancer and heart disease, MIT reported.  It consists of a mesh network of nanoparticles made from entwined polymers.  

"Now you have a gel that can change shape when you apply stress to it, and then, importantly, it can re-heal when you relax those forces. That allows you to squeeze it through a syringe or a needle and get it into the body without surgery," said Mark Tibbitt, a postdoc at MIT's Koch Institute for Integrative Cancer Research.

Gels that have been created in the past have been made through complex biochemical processes, such as engineered self-assembling proteins; this new gel requires only simple materials. In the study, the researchers demonstrated the groundbreaking gels could survive injection under the skin of mice, and successfully released one hydrophobic and one hydrophilic drug over the course of several days.

This type of gel stays in place after it is injected, which could allow medicine delivery to target specific tissues and regions of the body. The technique could allow medical professionals to use anti-angiogenesis drugs to treat macular degeneration (an age-related loss of vision). Current treatments for the condition require eye injections every month, but these new gels could reduce the frequency of these treatments by delivering the drugs slowly over time.

Another potential use for the new gels is to deliver cancer drugs to kill cancer cells left behind after surgery. The gel could be filled with a chemical that attracts cancer cells as well as a chemotherapy drug that would destroy them.

"Removing the tumor leaves behind a cavity that you could fill with our material, which would provide some therapeutic benefit over the long term in recruiting and killing those cells," said Koch Institute post-doctoral student Eric Appel. "We can tailor the materials to provide us with the drug-release profile that makes it the most effective at actually recruiting the cells."

The findings were published in a recent edition of the journal Nature Communications.