Gold Nanorods Target Pain Receptors for Relief

Researchers from Kyoto University’s Institute for Integrated Cell-Material Sciences (iCeMS) may have found a way to control cell functions in order to alleviate intractable pain.

In an optogenetic approach, tiny gold nanorods may be able to be injected to provide pain relief. The rods are 1-100 nanometers wide and long, which the team compared to a human hair that measures in at 100,000 nanometers wide.

Previous studies have shown that magnetic nanoparticles can activate the receptors in cell membranes called TRPV1 (transient receptor potential vanilloid type 1) which are responsible for pain. The problem with those strategies is that they often require genetic modification to the cells. The new method, however, does not call for modification and allows for a broader application.

The researchers “coated gold nanorods with a special type of protein that transports fat within the body known as a lipoprotein,” a news release explained. This was necessary so that the rods could bind to the TRPV1 receptors. Next, they heated the receptors with near-infrared light, which caused them to activate. This led to desensitization and thus, pain relief. The process was done safely without affecting the cell membranes.

Based on the study published in Angewandte Chemie International Edition, the gold nanorods are at least 1,000 times more effective at TRPV1 activation than traditional methods.

“The gold nanorods can be retained in the body for a prolonged period,” principal investigator Tatsuya Murakami, an associate professor at iCeMS, said in the statement. “Local injection of our gold nanorods might enable repetitive and on-demand treatment for people experiencing intractable pain because prior genetic engineering of the target cells is unnecessary.”