One of the greatest advances in modern medicine has been our ability to probe inside the living body, diagnosing and treating organs from the inside. Now, nanotechnology is bringing the day closer when we can probe inside individual, living cells. That possibility offers incredible promise for cancer treatment and a wide range of medical breakthroughs.

Probes designed to penetrate a cell and report on the conditions within that cell must be sufficiently small, exceedingly bright, and stable for a long time - material properties that are often mutually exclusive. Probes must also remain stable in the intracellular environment, and not disrupt the cell's normal biochemical functioning.

A recent article by David Conrad at NSTI's Nano World News documents the work of a research group at Old Dominion University led by X. Nancy Xu, Ph.D., prepared a series of silver nanoparticles. Although smaller than 100 nanometers in diameter, these particles are bright enough to be seen by eye using optical microscopy.

"One of the key advantages is that unlike fluorophores, fluorescent proteins, or even quantum dots, the silver nanoparticles do not photodecompose (fall apart) during extended illumination," explained Xu. Therefore, they can be used as a probe to continuously monitor dynamic events in living cells during studies that last for weeks or even months.

Researchers need detailed information about the biological processes and dynamics in living cells to aid in the detection and diagnosis of cancer.

Many traditional techniques for analysis require "fixing" cell samples prior to analysis. This process often destroys the precise intracellular architecture governing the network. Thus, the rate of a biochemical reaction occurring in a test tube could be quite different from that observed for the same reaction inside a cell. (photo NSTI)