Catch the light

Metal nanoparticle antennas can capture laser light and generate heat to perform localized molecular surgery

Credit: © 2007 ACS

When metal nanoparticles interact with laser light they absorb energy and their temperature increases. In a biological environment, this heat can be used to destroy surrounding tissue such as protein aggregates or tumours. Now, researchers in Germany from the Institute for Physical High Technology, Jen Lab GmbH and Friedrich-Schiller University have used gold nanoparticles to selectively induce local damage in chromosomes with nanoscale precision.

Using standard DNA hybridization techniques, Karsten König, Wolfgang Fritzsche and colleagues¹ positioned silver-coated gold nanoparticles on chromosomes and irradiated them with short laser pulses. Atomic force microscopy showed that the irradiated metal particles created nanoscale cavities, indicating highly localized destruction of the genetic material. Height changes in the nanoparticles suggest that damage is caused by partial ablation of the metal particles and their subsequent sinking into the chromosome. The degree of damage depends on a number of factors, including particle size, laser power and wavelength.

By labelling different DNA sequences with nanoparticles that respond to different wavelengths of light, this method could be used to selectively and simultaneously manipulate various genes using different lasers.