The idea for using DNA strands to trap nanoparticles in cages has been floating around for years, but scientists have been unable to trap nanoparticles efficiently. Naturally, nanoparticles tend to clump together at random in their devices. Subsequently, devices cannot be used for their technological applications as the internal structures are not ordered correctly.
Until recently, scientists have been coating gold nanoparticles with short sequences of single-stranded DNA. The DNA strands are designed in such a way that hydrogen bonds between them join together in three-dimensional space and hold the nanoparticles together. However, since the DNA strands have been randomly positioned on the nanoparticles, this technique was unable to overcome the problem of
clumping.Scientists Alexei Tkachenko and Nicolas Licata from the University of Michigan have devised a solution. They suggest using combinations of DNA helices with tipped ends and short sequences of single-stranded DNA. Only the complementary sequences of the DNA helix and single-stranded DNA will bind together, forming a tetrahedral cage around the nanoparticles (as seen in the image). The symmetry of the cage prevents 'clumping' and instead, the strands of the cages bind with others, linking the cages together.
This hypothesis is currently being tested, and success will mark a new age in nanotechnology. It also highlights the diversity of genetics, and a new area of research; the physical uses of DNA.
Reference:
Griggs, J. 2009, ‘DNA cages guide nanoparticles self-assembly’, New Scientist, [Available] http://www.newscientist.com/article/mg20126994.800-dna-cages-guide-nanoparticle-selfassembly.html, issue 2699, 17 March 2009, (accessed 22/3/09)
