Tiny, implantable golden rods may offer help to people whose pain is otherwise untreatable, a new study shows.

Thirty-four million Americans suffer from chronic pain for which they have not found an effective treatment.

Now, Kyoto University researchers have developed a novel technique using tiny gold rods that are 1/100th of a nanometer in width. In comparison, a human hair is 100,000 nanometers wide.

Scientists coated the nanorods with lipoprotein, a special type of protein that transports fat within the body.

This allowed the nanorods to bind with pain receptors known as TRPV1 (transient receptor potential vanilloid type 1), which brought pain relief.

Previous studies had shown that magnetic nanoparticles (tiny particles in the nano-range made out of magnetic materials) also provide some pain relief, but nanorods have been found to be more efficient.

The researchers are hoping their technique could result in an injectable on-demand treatment for people who suffer from intractable pain. The study is published in Angewandte Chemie International Edition.