Tobacco mosaic virus was "taught" to produce gold nanoparticles from salts
In a new work, scientists have created a genetically modified tobacco mosaic virus capable of recovering gold from the salt of hydrochloric acid. The resulting nanoparticles with a diameter of up to 40 nanometers had a crystalline structure and proved to be very stable.
The study was conducted by scientists from Lomonosov Moscow State University and the James Hutton Institute in the UK. The article by Love et al., A Genetically Modified Tobacco Mosaic Virus that can Produce Gold Nanoparticles from a Metal Salt Precursor is published in the journal Frontiers in Plant Science.
The tobacco mosaic virus is an RNA virus: its genetic information is "recorded" in an RNA molecule placed in a protein envelope. In early works, the potential of some peptide (i.e. short protein) sequences for the reduction of metal ions, including gold, from salts was shown. In their study, the scientists created a virus on the surface of which one of these peptides was presented. To do this, scientists have embedded a sequence of nucleic acids encoding it into the genome of the virus, which has already been fully decoded. Then a mixture of genetically engineered RNA and abrasive particles was rubbed into tobacco leaves.
Thus, the sequence of nucleic acids, carrying complete information about the structure of the virus, got into the plant cells, where viral proteins were synthesized on its basis. Since viral particles are capable of self-assembly, after about 16 days, the leaves showed signs of viral infection. After that, "ready-made" genetically modified viruses were isolated from them.
To test the ability of the created viral particles to restore gold, scientists incubated them for 32 hours with potassium tetrachlorourate (otherwise, hydrochloric acid salt). During this time, the solution changed its color from yellow to pale purple, which indicated the formation of gold nanoparticles. In control samples containing "wild" viruses (without a gold-reducing peptide), there was no qualitative change in color. The presence of gold nanocrystals was also confirmed by spectroscopic experiments.
Micrograph from an article in Frontiers in Plant Science – VMThe diameter of the crystals obtained in the experiments ranged from 10 to 40 nanometers, which corresponds to the characteristic sizes of nanoparticles used in biomedical research.
In addition, the technology described in this paper is less expensive than bacterial or yeast production, and does without the use of additional reducing reagents
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14.12.2015