The researchers coupled miniscule particles of silver, a metal that is not rejected by cells and is an efficient reflector of light, with a small portion of the HIV protein responsible for its highly efficient ability to enter a cell and its nucleus. In this case, the researchers harnessed only the ability of HIV to sneak past cellular defenses, while stripping away its ability to take over the cell's genetic machinery and cause disease.
"This combination takes advantage of the smallness of the nanoparticle and the 'delivery instructions' of the HIV protein," Gregas explained. "Once we can get that nanoparticle into the nucleus, we have many options. We can for example deliver some sort of payload and then observe its effects within the nucleus."
That's where a four-decades-old optical technique known as surface-enhanced Raman scattering (SERS) comes into play. It is used here as a sensitive imaging technique to demonstrate that the nanoparticles and their payloads successfully entered the nucleus.
When light, usually from a laser, is shined on a sample, the target molecule vibrates and scatters back its own unique light, often referred to as the Raman scatter. However, this Raman response is extremely weak. When the target molecule is coupled with a metal nanoparticle, the Raman response is greatly enhanced by the SERS effect -- often by more than a million times, Vo-Dinh said.
In the early 1980s, while at the Oak Ridge National Laboratory in Tennessee, Vo-Dinh and colleagues were among the first to demonstrate that SERS could be put into practical use to detect chemicals, including carcinogens, environmental pollutants and early markers of disease. At Duke, Vo-Dinh is pushing the boundaries of SERS technology for biomedical detection and molecular imaging.
"Our ultimate goal is to develop a nanoscale delivery system that can drop off its payload in this case nanoparticles with other agent
|Contact: Richard Merritt|