SNEAKING SPIES INTO A CELL`S NUCLEUS
Baku, October 1 (AZERTAC). Duke University bioengineers have not only figured out a way to sneak molecular spies through the walls of individual cells, they can now slip them into the command center -- or nucleus -- of those cells, where they can report back important information or drop off payloads.
Using silver nanoparticles cloaked in a protein from the HIV virus that has an uncanny ability to penetrate human cells, the scientists have demonstrated that they can enter the inner workings of the nucleus and detect subtle light signals from the “spy.”
In order for these nano-spies to be effective, they not only need to get through the cell`s first line of defense -- the cell wall -- they must be able to enter the nucleus.
The ultimate goal is to be able to spot the earliest possible moment when the genetic material within a cell begins to turn abnormal, leading to a host of disorders, especially cancer.
The finding also shows how drugs or other payloads might be delivered directly into the nucleus.
The Duke researchers reported their findings in a series of papers, culminating in the latest issue of Nanomedicine, which was published online. The research was supported by the National Institutes of Health.
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.
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.
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