The high sensitivity of localized surface plasmon resonance sensors to the local refractive index allows for the detection of single-molecule binding events. Though binding events of single objects can be detected by their induced plasmon shift, the broad distribution of observed shifts remains poorly understood. Here, we perform a single-particle study wherein single nanospheres bind to a gold nanorod, and relate the observed plasmon shift to the binding location using correlative microscopy. To achieve this we combine atomic force microscopy to determine the binding location, and single-particle spectroscopy to determine the corresponding plasmon shift. As expected, we find a larger plasmon shift for nanospheres binding at the tip of a rod compared to its sides, in good agreement with numerical calculations. However, we also find a broad distribution of shifts even for spheres that were bound at a similar location to the nanorod. Our correlative approach allows us to disentangle effects of nanoparticle dimensions and binding location, and by comparison to numerical calculations we find that the biggest contributor to this observed spread is the dispersion in nanosphere diameter. These experiments provide insight into the spatial sensitivity and signal-heterogeneity of single-particle plasmon sensors and provides a framework for signal interpretation in sensing applications.
- March 12, 2018
- Uncategorized
- Peter Zijlstra
Related Articles
Research paper published in Nanoscale
Dynamic single-molecule counting for the quantification and optimization of nanoparticle functionalization protocols DOI: doi.org/10.1039/C9NR10218C Matěj Horáček, Dion J. Engels, Peter Zijlstra Applications of colloidal particles in the fields of i.e. biosensors, molecular...
Molecular Plasmonics joins EHCI at TU/e
We are now a part of the newly founded Hendrik Casimir Institute, TU/e! https://www.tue.nl/en/research/institutes/eindhoven-hendrik-casimir-institute/
Correlative microscopy of single self-assembled nanorod dimers for refractometric sensing
DOI link: https://aip.scitation.org/doi/10.1063/5.0055135 Michael A. Beuwer, Peter Zijlstra* Single metallic particles and dimers of nanospheres have been used extensively for sensing, but dimers of particles provide attractive advantages because they...