Web Release Date: January 16,
Label-Free Plasmonic Detection of Biomolecular Binding by a Single Gold Nanorod
and
Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, and Division of Solid State Physics, Lund University, SE-22100 Lund, Sweden
Received for review August 16, 2007. Accepted November 13, 2007.
Abstract:
We report the use of individual gold nanorods as plasmonic transducers to detect the binding of streptavidin to individual biotin-conjugated nanorods in real time on a surface. Label-free detection at the single-nanorod level was performed by tracking the wavelength shift of the nanorod-localized surface plasmon resonant scattering spectrum using a dark-field microspectroscopy system. The lowest streptavidin concentration that was experimentally measured was 1 nM, which is a factor of 1000-fold lower than the previously reported detection limit for streptavidin binding by biotinylated single plasmonic nanostructures. We believe that the current optical setup is able to reliably measure wavelength shifts as small as 0.3 nm. Binding of streptavidin at 1 nM concentration induces a mean resonant wavelength shift of 0.59 nm suggesting that we are currently operating at close to the limit of detection of the system.
Download the full text: PDF | HTML
