Georgia Institute of Technology and Emory University researchers say that the specially-designed nanoparticles, which seek out hydrogen peroxide and emit light when they encounter it, could someday be used as a simple, all-purpose diagnostic tool to spot the earliest stages of any disease that involves chronic inflammation.
The production and role of Hydrogen peroxide, thought to be over-produced by cells at the early stages of most diseases, has not been determined as yet, because of the lack of imaging techniques.
The Georgia Tech and Emory nanoparticles may be the key to better understanding the role of hydrogen peroxide in the progression of many diseases and later play an important diagnostic role, said Niren Murthy, lead researcher.
"These nanoparticles are incredibly sensitive so you can detect nanomolar concentrations of hydrogen peroxide. That's important because researchers aren't yet certain what amounts of hydrogen peroxide are present in various diseases," Murthy said.
The decisive goal, however, is that the nanoparticles could some day be used as a simple, all-purpose diagnostic tool for most diseases. In the future, the nanoparticle would be injected by needle into a certain area of the body (for instance, the heart). If the nanoparticles encountered hydrogen peroxide, they would emit light. Should a doctor see a significant amount of light activity in the area, the doctor would know that the patient may be presenting early signs of a disease in that area of the body.
The Georgia Tech and Emory nanoparticles infiltrate deep tissue and operate at a high wave length, making them sensitive indicators of the presence of hydrogen peroxide produced by any sort of inflammation.
The nanoparticle polymer is made of peroxalate esters. A fluorescent dye (pentacene) is then encapsulated into the polymer. When the nano particles bump into hydrogen peroxide, they stimulate the dye, which then emits photons (or light) that can be detected in a simple, photon-counting scan.
"It's using this nanoparticle made of peroxalate esters that allows you to do this three component reaction in vivo. If you were to inject a peroxalate ester and a dye, they would go their own ways once in the body. With the nanoparticles, we can sequester both of these reagents within nanometers of each other, in vivo," Murthy said.
The goal was to maximize the wavelength of the particles, which determines the sensitivity in vivo. And if the particle's wavelength is high enough, it can penetrate the skin and display clearly on a scan.
The research team started with a nanoparticle that was made of dye and filled with peroxide esthers. They later realized that the reverse (a particle made of peroxalate esters and filled with dye) was more effective at imaging hydrogen peroxide, Murthy said.
The group will conduct further tests with the nanoparticles to confirm their safety and effectiveness.
The study will appear in the October issue of Nature Materials and was funded by the National Science Foundation (NSF) and the National Institutes of Health (NIH).