Tagging strands of DNA with tiny gold particles could allow scientists to switch genes on and off inside the body by remote control. The method could be used to tell cells when to produce specific proteins, such as insulin.
鈥淲e should be able to control almost any kind of biological process with this,鈥� says Kimberly Hamad-Schifferli at Massachusetts Institute of Technology.
Hamad-Schifferli and her team tagged strands of DNA with gold 鈥渘anocrystals鈥� measuring just 1.4 nanometres in diameter. A solution of the tagged DNA strands was then surrounded by a wire coil that produced a rapidly oscillating magnetic field.
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The researchers found that when the field was switching direction at one gigahertz (one billion times a second), electrical currents induced in the gold particle heated it up enough to break the weak bonds holding the twin strands of the DNA鈥檚 double helix together. 鈥淭he heat essentially unzips the DNA,鈥� says Hamad-Schifferli.
On and off
Unzipped DNA allows the cell to make so-called messenger RNA that in turn produces proteins for the body. Switching the magnetic field off makes the DNA reform into a double strand again, effectively switching off its ability to produce proteins.
Although the researchers have so far only produced the effect in a test tube, they hope to try it out in animals soon.
Independent experts agree the technique is step forward but believe it is so novel that applications are not likely to arrive soon. 鈥淭his is really interesting,鈥� says William Brown, at the Institute of Genetics at Nottingham University, UK. 鈥淏ut it might take some time before people work out how to use it effectively.鈥�
He suggests: 鈥淚f you could tag a protein with these crystals without affecting how they work, you could use the switching effect to work out what they do in the body.鈥�
Journal reference: Nature (vol 415, p 152)