A breakthrough that could rewrite the future of brain cancer treatment. U.S. scientists have developed a nasal spray nanomedicine that can slip through the nose, travel directly into the brain, and activate the immune system to destroy glioblastoma — one of the deadliest and most treatment-resistant cancers known. Instead of surgery, chemotherapy, or risky injections into the brain, researchers engineered microscopic particles called spherical nucleic acids. Each one carries genetic instructions