Rational Selection of Gold Nanorod Geometry for Label-Free Plasmonic Biosensors

Nusz, Greg J.; Curry, Adam; Marinakos, Stella M.; Wax, Adam; Chilkoti, Ashutosh

doi:10.1021/nn8006465

Cited by 236 publications

(295 citation statements)

References 76 publications

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“…The structure and thickness layer of the peptide recognition element on the gold surface was also investigated using molecular dynamic simulations (described in the supplemental section). The atomistic structure of the cTnI binding peptide shows that N-terminal Phe 1 and C-terminal Cys 13 residues are in close contact with the gold surface (Fig. 5B).…”

Section: Resultsmentioning

confidence: 99%

Peptide Functionalized Gold Nanorods for the Sensitive Detection of a Cardiac Biomarker Using Plasmonic Paper Devices

Tadepalli

Kuang

Jiang

et al. 2015

Sci Rep

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The sensitivity of localized surface plasmon resonance (LSPR) of metal nanostructures to adsorbates lends itself to a powerful class of label-free biosensors. Optical properties of plasmonic nanostructures are dependent on the geometrical features and the local dielectric environment. The exponential decay of the sensitivity from the surface of the plasmonic nanotransducer calls for the careful consideration in its design with particular attention to the size of the recognition and analyte layers. In this study, we demonstrate that short peptides as biorecognition elements (BRE) compared to larger antibodies as target capture agents offer several advantages. Using a bioplasmonic paper device (BPD), we demonstrate the selective and sensitive detection of the cardiac biomarker troponin I (cTnI). The smaller sized peptide provides higher sensitivity and a lower detection limit using a BPD. Furthermore, the excellent shelf-life and thermal stability of peptide-based LSPR sensors, which precludes the need for special storage conditions, makes it ideal for use in resource-limited settings.Plasmonic biosensors based on localized surface plasmon resonance (LSPR) are highly attractive for lab-on-chip devices that are cost-effective and used in point-of-care biodiagnostics 1 . LSPR of metal nanostructures is shown to be sensitive enough to differentiate various inert gases (refractive index difference on the order of 3 × 10 −4 refractive index units (RIU)), probe the conformational changes of individual biomacromolecules, detect single biomolecule binding events, monitor the kinetics of catalytic activity of single nanoparticles and even optically detect a single electron [2][3][4][5][6] . In the design of LSPR-based biosensors, two factors are of prime importance: (i) the bulk refractive index sensitivity and the electromagnetic decay length of the nanostructures employed as optical transducers. There have been numerous studies that focus on the design, synthesis and the validation of novel plasmonic nanostructures with high bulk refractive index sensitivity [7][8][9] . However, studies focusing on understanding the effect of the electromagnetic (EM) decay length on the ultimate performance of the LSPR-based biosensor are limited 10,11 . Although the decay in the sensitivity of plasmonic nanostructures with distance has been widely investigated 12,13 , to the best of our knowledge, a direct comparison of the sensitivity of LSPR biosensors based on recognition layers of different sizes (i.e., thickness of the recognition layer) is largely unexplored.

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Section: Resultsmentioning

confidence: 99%

Peptide Functionalized Gold Nanorods for the Sensitive Detection of a Cardiac Biomarker Using Plasmonic Paper Devices

Tadepalli

Kuang

Jiang

et al. 2015

Sci Rep

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“…LSPR spectroscopy is highly sensitive to the small refractive-index changes of the environment surrounding nanoscale metal particles and has been reported to detect the presence of as few as tens to hundreds of nearby molecules [16,17]. This sensitivity arises from the resonant coupling of incident light to the collective oscillation of conduction electrons in the metal modified by the presence of the surrounding medium, which may have its own distinct elec-FIG.…”

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confidence: 99%

On the linear response and scattering of an interacting molecule-metal system

Masiello

Schatz

2010

The Journal of Chemical Physics

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A many-body Green's function approach to the microscopic theory of plasmon-enhanced spectroscopy is presented within the context of localized surface-plasmon resonance spectroscopy and applied to investigate the coupling between quantum-molecular and classical-plasmonic resonances in monolayer-coated silver nanoparticles. Electronic propagators or Green's functions, accounting for the repeated polarization interaction between a single molecule and its image in a nearby nanoscale metal, are explicitly computed and used to construct the linear-response properties of the combined molecule-metal system to an external electromagnetic perturbation. Shifting and finite lifetime of states appear rigorously and automatically within our approach and reveal an intricate coupling between molecule and metal not fully described by previous theories. Self-consistent incorporation of this quantum-molecular response into the continuum-electromagnetic scattering of the molecule-metal target is exploited to compute the localized surface-plasmon resonance wavelength shift with respect to the bare metal from first principles.Ever increasing experimental interest in a variety of plasmon-enhanced molecular spectroscopies has provided impetus for the development of a corresponding assortment of theoretical descriptions of these phenomena [1,2,3,4,5,6]. Linear molecular spectroscopies such as Raman and fluorescence have found their plasmonenhanced analogs in surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence; both are now routinely realized in the extreme limit of singlemolecule detection; see, e.g., Refs. [7,8,9,10]. And plasmon-enhanced versions of n-wave mixing and hyperRaman scattering [11,12], as well as other nonlinear spectroscopies, are rapidly being explored as ultrasensitive probes of molecular structure complementary to those linear. Conversely, spectroscopy of the plasmon itself, either localized to metal particles or propagating across metal surfaces [13], and embedded within a potentially resonant molecular environment [14,15] forms the basis for yet another promising direction of related research. Outside of the laboratory, the challenge remains to develop theories that are rich enough to describe the basic physics relevant to each, yet are simultaneously practical enough to implement numerically for real systems of current experimental interest.Here we present the first numerical implementation of a new and general many-body Green's function formalism that is capable of describing a variety of plasmonenhanced linear spectroscopies and apply it to model recent localized surface-plasmon resonance (LSPR) spectroscopy and molecular sensing experiments. LSPR spectroscopy is highly sensitive to the small refractive-index changes of the environment surrounding nanoscale metal particles and has been reported to detect the presence of as few as tens to hundreds of nearby molecules [16,17]. This sensitivity arises from the resonant coupling of incident light to the collective oscillation of conduction elect...

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“…3 The localized surface plasmon resonance (LSPR) on gold or silver nanoparticles/nanostructures has been used for enhancing fluorescent detection of biological samples. 4,5 On the other hand, the strong optical near-field near plasmonic nanostructure can generate optical trapping force in liquid environment. This localized near-field helps attracting biomolecules to the nanostructures with a trapping force in femto-newton range.…”

Section: Author(s) All Article Content Except Where Otherwise Notedmentioning

confidence: 99%

Enhancing DNA binding rate using optical trapping of high-density gold nanodisks

et al. 2014

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We present the dynamic study of optical trapping of fluorescent molecules using high-density gold nanodisk arrays. The gold nanodisks were fabricated by electron beam lithography with a diameter of 500 nm and a period of 1 μm. Dark-field illumination showed ∼15 times enhancement of fluorescence near edges of nanodisks. Such enhanced near-field generated an optical trapping force of ∼10 fN under 3.58 × 103 W/m2 illumination intensity as calculated from the Brownian motions of 590 nm polystyrene beads. Kinetic observation of thiolated DNA modified with Cy5 dye showed different binding rates of DNA under different illumination intensity. The binding rate increased from 2.14 × 103 s−1 (I = 0.7 × 103 W/m2) to 1.15 × 105 s−1 (I = 3.58 × 103 W/m2). Both enhanced fluorescence and binding rate indicate that gold nanodisks efficiently improve both detection limit and interaction time for microarrays.

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Rational Selection of Gold Nanorod Geometry for Label-Free Plasmonic Biosensors

Cited by 236 publications

References 76 publications

Peptide Functionalized Gold Nanorods for the Sensitive Detection of a Cardiac Biomarker Using Plasmonic Paper Devices

Peptide Functionalized Gold Nanorods for the Sensitive Detection of a Cardiac Biomarker Using Plasmonic Paper Devices

On the linear response and scattering of an interacting molecule-metal system

Enhancing DNA binding rate using optical trapping of high-density gold nanodisks

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