National Cancer Institute’s Alliance for Nanotechnology in Cancer has another fascinating review article. This one is about the future of Asimov-like intracellular adventures, with nanosputniks, functioning nanoprobes sent to explore a living cell. [btw, the term “nanosputnik” is coined for the first time right here right now to describe exploratory nanoparticles (as far as we know) -ed.]
Unlike planetary probes, those 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. Recently, a research group at Old Dominion University led by X. Nancy Xu, Ph.D., prepared a series of silver (Ag) nanoparticles that meet many of the criteria listed above. Although smaller than 100 nanometers (nm) 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. Because the color of the scattered light from nanoparticles depends upon their size (Figure 1), they have been used to measure the change in single membrane pores in real time using a technique known as dark-field optical microscopy. Intracellular and extracellular nanoparticles can also be differentiated by the intensity of light scattering (Figure 2). “The primary challenge now is to develop methods for modifying the surface of the nanoparticles to make them more biocompatible, so that more biological processes can be observed without perturbing or destroying the cell’s intrinsic biochemical machinery,” said Xu.
Read the whole thing…