One of the ultimate goals of molecular biology is to watch how single molecules work at physiological conditions.
This involves high local concentrations in the micromolar range, and calls for more than three orders of magnitude shrinking of the detection volume as compared to conventional optical microscopes. Hence, new nanotechnology tools need to be introduced in order to reach ultra-small detection volumes and turn single molecules into bright light sources.
The groups led by ICREA Professors at ICFO, Maria Garcia-Parajo and Niek van Hulst, in collaboration with researchers from the Fresnel Institute report in Nature Nanotechnology on a novel “antenna-in-box” platform for single molecule fluorescence detection with unprecedented resolutions and sensitivity. The innovative approach combines a plasmonic gap antenna for ultra-high fluorescence enhancement with a metal nanoaperture for optimized background-free operation. It allows for 1100-fold fluorescence brightness enhancement together with detection volumes down to 58 zeptoliters (1 zL = 10-21L), realizing a gain of four orders of magnitude as compared to classical microscopes.
The antenna-in-box offers a highly efficient platform for nanoscale biochemical assays with single molecule sensitivity at physiological conditions. Its versatile design also provides a leap towards ultra-bright optical nanosources.
Link to paper