A painkiller you switch on with light — relief exactly where it hurts, and nowhere else

Strong painkillers work everywhere in the body at once, which is where their risks come from. A team led by Weill Cornell Medicine and the University of Pennsylvania has built an experimental alternative, AM-3: a morphine-based compound that changes shape under different colours of light, so its painkilling strength can be turned up at the sore spot and down everywhere else. In early lab models, including bone cancer pain, shining light on the pain site gave morphine-like relief without the usual signs of tolerance or constipation — and because the compound barely reaches the brain, the team hopes to sidestep the effects behind addiction and slowed breathing. The work, published in Cell, is still at the preclinical stage, and the researchers are now designing versions that respond to gentler, tissue-friendly red light.

SDG 3 · Good health and well-being — Mechanism: tech innovation