Electrical DNA

Scientists have made silver nanowires based on DNA

MIPT Press Service

An international group of scientists from Russia (including from MIPT) and Israel created nanowires from DNA molecules and silver nanoparticles. The results of the study (Eidelshtein et al., Synthesis and Properties of Novel Silver-Containing DNA Molecules) are published in the journal Advanced Materials and placed on the cover.

Every year electronic circuits and devices become more compact and more productive. However, traditional electronics is approaching its technological limit, and the production of effective nanoelements remains an important task for the miniaturization and improvement of electronic and optical devices. 

To solve this problem, the transition to molecular electronics (based on the use of individual molecules as electronic elements) is promising. Nanowires can be the basic elements of many circuits, and DNA molecules could be perfect for this due to their structure and ability to self-organize.

"If DNA molecules reproducibly conducted an electric charge, it would be easy to make a new generation of electronic circuits and electrical devices. However, the conductivity of DNA is very low in some cases, especially if the molecule is fixed on a solid substrate. We found that DNA consisting of guanine-cytosine pairs can interact with silver nanoparticles and “take” the atoms of this metal. This is how its metallization occurs," comments Dmitry Klinov, head of the Laboratory of Medical Nanotechnology at the FNCC FHM and lecturer at the Department of Molecular and Translational Medicine at MIPT.

DNA is of interest not only as a repository of genetic information, but also as a candidate for the role of nanowires for molecular electronics. The authors of the article have previously discovered interesting properties of this molecule. Firstly, it is capable of exhibiting superconducting properties if placed between two superconductors (induced superconductivity). Secondly, DNA molecules are able to carry out charge transport independently, but the efficiency depends on the substrate on which they are deposited. Charge transfer through DNA can be enhanced by the arrangement of metal atoms along the chain, but it is difficult to achieve uniform coating, and the remaining non-metallized DNA fragments impair the ability to conduct electricity. The authors of the work noticed that DNA consisting of a guanine chain and a cytosine chain complementary to it (GC-DNA) can be uniformly metallized with silver atoms.

The metallization process is quite simple: GC-DNA is added to a solution of silver nanoparticles coated with oligonucleotides and left for 2-3 days. The particles interact with DNA and "give" their atoms to it (see diagram). As a result of this procedure, DNA is evenly coated with silver atoms. Scientists call the resulting molecule E-DNA ("E" – electric). E-DNA becomes more rigid and resistant to mechanical deformations; in addition, it cannot be destroyed by enzymes specific to the original molecule. The height of E-DNA observed in an atomic force microscope increases from 0.7 nm to 1.1 nm.

Distribution of silver nanoclusters along the DNA chain due to diffusion.

"Since the metal atoms are evenly spaced along the DNA molecule, we expect that such a nanowire will be a good conductor," explains Dmitry Klinov.

In further studies, the authors will continue to study the properties of E-DNA and the mechanisms of metallization.

Portal "Eternal youth" http://vechnayamolodost.ru  08.12.2016