The researchers designed sphere nanoparticles that can be injected into the bloodstream and shape shift when triggered by an enzyme.

“We wanted to come up with a new approach. Specifically, we wanted to design switchable materials that we could inject in one shape and have them change to another between the blood and tumors,” Gianneschi said to UCSD News.

The cancer-associated enzymes, matrix metalloproteinases — MMP-2 and MMP-9 — prompt the nanoparticles to morph into a scaffold within the cancerous tumors.

“We figured out how to make an autonomous material that could sense its environment and change accordingly,” Gianneschi said to UCSD News.

The nanoparticles are hydrophobic on one end while hydrophilic on the other end. Because of this, they form spheres when put in a solution to be injected into the vein. When mixed with the MMP enzymes, the nanoparticles opened up into netlike threads.

The researchers then tested the nanoparticles in mice with fibrosarcomas, a human cancer that produces MMP enzymes in high levels. In order to see when the spheres changed shape, they added fluorescent dyes, Forster Resonance Energy Transfer, that lit up after the nanoparticles morphed. 

Currently, the researchers are aiming to develop nanoparticles with infrared dye so they can see the tumors deeper within the body.