DNA as building blocks in nanotechnology

Complex nanostructures can be built from solutions containing nucleic acids. Photo courtesy of photocase.com

In the last few years, development in nanotechnology has enabled us almost literally to construct new molecules by using individual atoms as building blocks in an ‘atom by atom’ approach. This opens up a unique opportunity for designing completely new chemical and material products with a high degree of control of the emergent functional properties.  Biological molecules are especially attractive for the nanoscientists as building blocks due to their spatial complexity, their self-assembling properties and the many diverse ways in which biological molecules can be assembled. In a new paper, scientists from the Russian Academy of Science show that the most promising building blocks are the nucleic acids found for instance in DNA. Their superior properties include their difference in length from a few nucleotides to chains several of micrometres long, the ability of the nitrogen bases to chemically react with a  long host of other compounds and of course the ability of strands of nucleic acids to bond with other strands of nucleic acids to form complex three-dimensional structures.

Several approaches can be used to design nucleic acids. The ‘step by step design’ approach modifies natural occurring strands by adding sticky ends to different strands which allows them to join into new structures in subsequent steps. However, this approach requires large expenditures and often produces quite unpredictable results. A second approach, ‘the entropy condensation’ approach, relies on changing the entropy of an aqueous solution of salts and nucleic acids. Evaporation of the salts results in spontaneous ordering of the nucleic acids. A third similar but opposite approach is ‘the enthalpy condensation’, which relies on the attraction between neighbouring nucleic acid, when the phosphor groups are chemically neutralised. This approach again results in spontaneous ordering of complex structures. The last approach is the so-called ‘all at once design’ approach. This relies on forming cross-links at many different sites in neighbouring strands and thus to built a new complex structure in one go. This is done by embedding the nucleic acids in a scaffold of liquid crystalline structures and then creating cross links by phase exclusion from water-salt solutions. The ‘all at once design’ holds the greatest potential for targeted design of DNA like nanostructures, but more research and a refinement of the techniques involved are required to realise the potential.

The potential application of DNA-like nanostructures include targeting guides for drugs in medicine, as biosensors and as optical filters or molecular sieves in electronic and optic appliances.

Source: 

Yevdokimov, Y. M. and Sytchev, V. V. (2007). Nanotechnology and nucleic acids. The Open Nanoscience Journal 1, 19-31.

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