Scientists have developed a technique that could lead to therapies for pain relief in people with intractable pain, potentially including cancer-related pain. The team coated gold nanorods with a special type of protein that transports fat within the body known as a lipoprotein. This allowed the nanorods to bind efficiently to nerve cell membranes bearing a pain receptor. Gold nanorods are tiny rods that are 1-100 nanometers wide and long. In comparison, a human hair is 100,000 nanometers wide.