Glass-blowing at the nanoscale

By James Dacey

(Courtesy: Alain Herzog/EPFL)

From the Romans to the studio artists of today, glass blowing is as much an art form as it is a technical discipline. In the same spirit as this creative lineage, a group of researchers in Switzerland has invented a technique for creating nano-sized capillary tubes of bespoke sizes.

The scientists at École Polytechnique Fédérale de Lausanne (EPFL) realized that they could alter the ends of ultrathin quartz tubes by careful remoulding using a scanning electron microscope. The tubes soften because glass is a non-conductive material, so electrons from the microscope accumulate in the material. The person operating the microscope can then carefully shape the neck of individual capillaries by altering the voltage and electric field strength, creating very narrow tips.

In the image above you can see how the researchers used the technique to shape the necks of quartz tubes to a few nanometres from an original 200 nm, publishing their findings in Nano Letters.  The team has registered a patent for the technique and believes it could have applications beyond the laboratory. “We can imagine industrial applications in ultrahigh-precision printers, as well as opportunities in surgery, where micro-pipettes of this type could be used at a cell’s scale,” says Aleksandra Radenovic of the EPFL’s Laboratory of Nanoscale Biology.