Highly Tunable Infrared Extinction Properties of Gold Nanocrescents

Bukasov, Rostislav; Shumaker‐Parry, Jennifer S.

doi:10.1021/nl062317o

Cited by 273 publications

(275 citation statements)

References 41 publications

Supporting

Mentioning

259

Contrasting

Unclassified

Order By: Relevance

“…Because of this exposed sharp tip, the local refractive index of a molecularscale volume in the solution can be monitored by tracking the LSPR peak of a single bipyramid. It is this extreme localization of the sensing volume, which is absent in nanoparticles of other shapes [4,[12][13][14][15][16][17][18] that makes the bipyramid a strong candidate particle for single molecule detection.…”

Section: Resultsmentioning

confidence: 99%

A single molecule immunoassay by localized surface plasmon resonance

et al. 2010

View full text Add to dashboard Cite

Noble metal nanoparticles exhibit sharp spectral extinction peaks at visible and near-infrared frequencies due to the resonant excitation of their free electrons, termed localized surface plasmon resonance (LSPR). Since the resonant frequency is dependent on the refractive index of the nanoparticle surroundings, LSPR can be the basis for sensing molecular interactions near the nanoparticle surface. However, previous studies have not yet determined whether the LSPR mechanism can reach the ultimate sensing limit: the detection of individual molecules. Here we demonstrate single molecule LSPR detection by monitoring antibody-antigen unbinding events through the scattering spectra of individual gold bipyramids. Both experiments and finite element simulations indicate that the unbinding of single antigen molecules results in small, discrete <0.5 nm blue-shifts of the plasmon resonance. The unbinding rate is consistent with antibody-antigen binding kinetics determined from previous ensemble experiments. According to these results, the effective refractive index of a single protein is approximately 1.54. LSPR sensing could therefore be a powerful addition to the current toolbox of single molecule detection methods since it probes interactions on long timescales and under relatively natural conditions.

show abstract

Section: Resultsmentioning

confidence: 99%

A single molecule immunoassay by localized surface plasmon resonance

et al. 2010

View full text Add to dashboard Cite

show abstract

“…However, the figure of merit (FOM) values, which are refractive index sensitivities divided by plasmon resonance linewidths, of LSPR sensors are generally 1-2 orders of magnitude smaller than those based on PSPRs (Supplementary Tables S1 and S2). Owing to strong radiative damping, the LSPRs of metal nanostructures generally exhibit broad resonance peaks, which result in small FOM values and in turn limit the performances of LSPR sensors [7][8][9] .…”

mentioning

confidence: 99%

Plasmonic gold mushroom arrays with refractive index sensing figures of merit approaching the theoretical limit

et al. 2013

View full text Add to dashboard Cite

Localized surface plasmon resonance (LSPR)-based sensing has found wide applications in medical diagnosis, food safety regulation and environmental monitoring. Compared with commercial propagating surface plasmon resonance (PSPR)-based sensors, LSPR ones are simple, cost-effective and suitable for measuring local refractive index changes. However, the figure of merit (FOM) values of LSPR sensors are generally 1-2 orders of magnitude smaller than those of PSPR ones, preventing the widespread use of LSPR sensors. Here we describe an array of submicrometer gold mushrooms with a FOM reaching B108, which is comparable to the theoretically predicted upper limit for standard PSPR sensors. Such a high FOM arises from the interference between Wood's anomaly and the LSPRs. We further demonstrate the array as a biosensor for detecting cytochrome c and alpha-fetoprotein, with their detection limits down to 200 pM and 15 ng ml À 1 , respectively, suggesting that the array is a promising candidate for label-free biomedical sensing.

show abstract

“…Therefore, the possibility of quantitatively examining how the edge rounding at the sharp boundary will alter the optical responses (particularly, the field enhancement and light harvesting property) has great significance on both theoretical and practical levels. While many nanostructures with blunt edges have been specifically investigated with numerical [12][13][14] or experimental methods [9][10][11][15][16][17][18], there has never been a systematic strategy reported so far to analytically deal with this problem. In this Letter, we propose an analytical model for a general class of blunt plasmonic devices by applying conformal mappings to the truncated metallodielectric system associated with the singular structures.…”

mentioning

confidence: 99%

Broadband Light Harvesting Nanostructures Robust to Edge Bluntness

et al. 2012

View full text Add to dashboard Cite

Metallic structures with sharp corners harvest the energy of incident light through plasmonic resonances, concentrating it in the corners and greatly increasing the local energy density. Despite its wide array of applications, this effect is normally strongly dependent on how sharp the corners are, presenting problems for fabrication. In this Letter, an analytical approach is proposed, based on transformation optics, to investigate a general class of plasmonic nanostructures with blunt edges or corners. Comprehensive discussions are provided on how the geometry affects the local field enhancement as well as the frequency and energy of each plasmonic resonance. Remarkably, our results evidence the possibility of designing broadband light harvesting devices with an absorption property insensitive to the geometry bluntness.

show abstract

Highly Tunable Infrared Extinction Properties of Gold Nanocrescents

Cited by 273 publications

References 41 publications

A single molecule immunoassay by localized surface plasmon resonance

A single molecule immunoassay by localized surface plasmon resonance

Plasmonic gold mushroom arrays with refractive index sensing figures of merit approaching the theoretical limit

Broadband Light Harvesting Nanostructures Robust to Edge Bluntness

Contact Info

Product

Resources

About