Biomolecular Recognition Based on Single Gold Nanoparticle Light Scattering

Abstract

A method for biomolecular recognition is reported using light scattering of a single gold nanoparticle functionalized with biotin. Addition of streptavidin and subsequent specific binding events alter the dielectric environment of the nanoparticle, resulting in a spectral shift of the particle plasmon resonance. As we use single nanoparticles showing a homogeneous scattering spectrum, spectral shifts as small as 2 meV can be detected.

Quantized plasmon quenching dips nanospectroscopy via plasmon resonance energy transfer

“…The plasmon resonance of gold and silver nanoparticles conjugated with various biomolecules 12,13 has been studied. Due to the mismatch between the typical biomolecular electronic resonance modes in ultraviolet wavelengths and nanoparticle plasmon resonance modes in visible wavelengths, only the shift of plasmon resonance peak is observed.…”

Influence of the tip in near-field imaging of nanoparticle plasmonic modes: Weak and strong coupling regimes

“…19͒ has managed to map both the local amplitude and phase of the plasmon modes by interferometric detection of the antenna fields scattered by a scanning atomic force microscope tip. [20][21][22][23][24] However, the antenna optical response is extremely sensitive to environmental changes, 5,8,9 thus the process of measurement of its near field may result in the modification of the antenna modes, similar to probe-induced modifications in other nanophotonic systems. [25][26][27][28] In this work we address this issue, presenting a basic understanding of the near-field coupling between s-SNOM probes and plasmonic nanoantennas ͑here gold nanodisks͒.…”

“…[1][2][3] The ability of plasmons to act as the interface between far-field radiation and nanoscale confined near fields has generated promising prospects in plasmon-enhanced spectroscopy, 4 optical nanoimaging, 5 electromagnetic signal guiding, 6,7 and biosensing applications, 8,9 among others. The potential of surface plasmons to decay radiatively, as well as nonradiatively, depending on the particular conformation and environment around them is the basis for most of these applications.…”

Optical trapping and manipulation of plasmonic nanoparticles: fundamentals, applications, and perspectives

“…122 Metallic nanoparticles larger than 40 nm have huge scattering cross sections and can be easily imaged directly in a dark-eld microscope. 123,124 Particles smaller than this predominantly absorb light, rather than scatter it, and down to sizes of only a few nanometers can be imaged, e.g. through photothermal imaging.…”

“…141,142 This has been used to monitor the binding and release of single molecules and proteins to gold nanoparticles by measuring a shi of the plasmon resonance frequency caused by a small variation of the local refractive index. 123,143 If two particles are brought in close proximity to each other the coupling between the individual plasmons can generate a strongly enhanced, localized electric eld called a plasmonic 'hot-spot'. Strongly coupled plasmonic nanostructures are particularly well suited to build biosensor-and spectroscopy devices as they have been shown to enhance Raman scattering and uorescence intensity and also shape the emission spectrum of single molecules that are positioned in the nanoantenna gap.…”