Hot Particles For Graphene Nanopores

Interest in nanoscopic holes has blossomed thanks largely to DNA sequencers based on nanopores formed from proteins. But researchers are becoming increasingly keen on pores in solid-state materials, such as graphene, because they can accommodate extra onboard optical or electronic nanostructures to enhance or expand a device’s biosensing abilities. Scientists typically pursue such nanoengineering feats one pore a time, making them difficult to scale up. An international research team led by Luke P. Lee of the University of California, Berkeley, has now developed a method that creates multiple graphene nanopores at once, each with a built-in antenna (Nano Lett. 2014, DOI: 10.1021/nl503159d). The researchers drop-cast gold nanoparticles onto a graphene substrate and then hit the particles with laser light. The light heats the particles to an estimated 680 °C—hot enough to oxidize graphene—and generates a radiative force that scoots the particles along the surface, leaving voids in their wake. After the laser is switched off, metal particles remain at each pore’s mouth. The team showed that these gold antennae can boost the optical signals from fluorescent biomolecules near the pore.