RNA in control

RNA molecules can be used as scaffolds for the synthesis of CdS nanocrystals of the same size

Credit: © 2006 ACS

The properties of semiconductor nanocrystals are largely dictated by their size, and so the control of this is one of the most important aspects of their synthesis. One way to address this issue is to use a template of a given size to direct their growth. Large biomolecules, with their deliberate and defined shapes necessary to carry out precise cellular functions, are ideal candidates.

Now, Shana Kelley and co-workers¹ at Boston College in the US have used RNA molecules as scaffolds for the formation of CdS nanocrystals. One particular class of these molecules — known as transfer RNAs (tRNAs) — are an essential part of the cellular machinery that makes proteins. These L-shaped molecules are roughly 5 nm in diameter, and were shown to template the formation of stable, well-dispersed 6-nm tRNA–CdS nanocrystals. In the absence of tRNA, only poorly soluble aggregates were produced.

Furthermore, the importance of using a template with a well-defined shape was underscored when the experiment was repeated with a mutant tRNA molecule deliberately designed to have no organized three-dimensional structure. In this case, a broader range of nanocrystal sizes was observed.