The two techniques used in the new study take very different approaches to combat cancer. One is a drug that blocks the production of PD-L1 – molecules produced in great numbers by tumors that attack and kill T cells, the foot-soldiers of the immune system.
The second is called photothermal therapy, which is based around star-shaped nanoparticles made of gold. These nanostars are injected into the patient, where they tend to cluster inside tumors, and once there, they’re blasted with lasers from outside the body. That heats up the gold and roasts the cancer cells from the inside. Golden nanostars have been used in the past to deliver drugs right into the heart of tumors, but in this case that all-important shape helps capture the energy of the laser more efficiently.
“The nanostar spikes work like lightning rods, concentrating the electromagnetic energy at their tips,” says Tuan Vo-Dinh, lead author of the study. “We’ve experimented with these gold nanostars to treat tumors before, but we wanted to know if we could also treat tumors we didn’t even know were there or tumors that have spread throughout the body.”