Label-free plasmonic detection of biomolecular binding by a single gold nanorod.
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.
Nusz
Greg J
GJ
Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.
Marinakos
Stella M
SM
Curry
Adam C
AC
Dahlin
Andreas
A
Höök
Fredrik
F
Wax
Adam
A
Chilkoti
Ashutosh
A
D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin / Q000032:analysis / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D018625:Microscopy, Atomic Force / Q000379:methods; D043942:Nanotubes / Q000737:chemistry*; D010316:Particle Size; D012680:Sensitivity and Specificity; D019809:Streptavidin / Q000032:analysis / Q000737:chemistry; D020349:Surface Plasmon Resonance / Q000379:methods; D013499:Surface Properties; D013997:Time Factors
D001710:Biotin; D006046:Gold; D019809:Streptavidin