Calibration of Dynamic Molecular Rulers Based on Plasmon Coupling between Gold Nanoparticles

Pairs of noble metal nanoparticles can be used to measure distances via the distance dependence of their plasmon coupling. These "plasmon rulers" offer exceptional photostability and brightness; however, the advantages and limitations of this approach remain to be explored. Here we report detailed plasmon peak versus separation calibration curves for 42- and 87-nm-diameter particle pairs, determine their measurement errors, and describe experimental procedures to improve their performance in biology, nanotechnology, and materials sciences.