KA-POW!

Researchers in Japan have found a way to separate nanometre-sized particles in a water-filled capillary using a laser-induced shockwave. The study, published in Analytical Chemistry,¹ describes the microscopic chromatographic technique, termed laser-induced shockwave chromatography, that the authors say shows advantages compared with normal chromatography, particularly in terms of its speed and applicability to sticky and absorbing polymers.

To perform the separation, a single laser pulse is fired at a point within the water-filled capillary, turning the water within into super-hot plasma. The plasma expands quickly, sending a shockwave along the capillary and carrying nearby particles with it. The distance the shockwave carries the particles depends on their sizes; larger particles gain more momentum from the blast and so travel further.

The technique was tested on proteins, their aggregates and inorganic nanoparticles and found it was effective on particles between 9–300 kDa. Using it on nanoparticles, the researchers were able to separate particles differing in size by only a few nanometres.

The study concludes that the main advantage of this technique is its speed: The shockwave travels through the capillary in a fraction of a second, moving the particles less than a millimetre, which the study claims would make it suitable for lab-on-a-chip devices.

1. T. Nagahara, N. Ichinose and S. Nakamura, Anal. Chem., 83(7), 2416–2419 (2011).

This story originally appeared in The Column. Click here to view that issue.