Tiny laser-triggered nanoparticles can wipe out targeted tumours in mice, and prime the immune system to eliminate more remote cancers with the help of systemic immune-activating drugs.

Researchers at Soochow University’s Institute of Functional Nano and Soft Materials combined three clinically approved products — a biodegradable plastic, an immune response modifying drug, and a chemical that gives off immense heat in the presence of near-infrared light — into a single nanoparticle much narrower than a hair.

They implanted mice with either breast or colon cancer cells at two sites in the body to mimic a primary tumour and a distant metastasis. They then injected the nanoparticles into one tumour and shone the laser. This destroyed the targeted tumour and primed the body for an anti-cancer response. Adding a so-called checkpoint inhibitor that attacks a critical negative regulator of immune cells helped destroy the non-targeted tumours as well.