Plasmon Rulers as Dynamic Molecular Rulers in Enzymology

Reinhard, Björn M.; Yassif, Jaime; Vach, Peter J.; Liphardt, Jan

doi:10.1016/s0076-6879(10)75008-4

Cited by 10 publications

(13 citation statements)

References 38 publications

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“…The DNA tether is flexible, however, and a color change due to decreased interparticle distance is produced whenever there is a shortening of the tether. There are many biochemical processes that involve the interaction of DNA with other molecules, these interactions can result in the folding or buckling of the DNA tether. , As such, these processes can be monitored by the plasmonic dimer color change as the interparticle distance is decreased. This device has been used to study DNA-binding enzymes, specifically the type II restriction endonuclease Eco RV, an enzyme that bends the DNA prior to splicing it. , In addition to the study of DNA–protein dynamics, there are also small molecules of therapeutic importance in cancer (e.g., cisplatin) that are known to bend and kink DNA chains, interfering with the cell reproductive cycle.…”

Section: Applicationsmentioning

confidence: 99%

Plasmons in Strongly Coupled Metallic Nanostructures

et al. 2011

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Section: Applicationsmentioning

confidence: 99%

Plasmons in Strongly Coupled Metallic Nanostructures

et al. 2011

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“…nanoparticles. Published results highlight that the plasmon resonance of coupled particle pairs radically depends on the interparticle distance. − ,,,− ,− Moreover, in the cases when the incident light polarization coincides with the direction of the axis passing through the centers of particles, the fractional shift Δλ/λ 0 = (λ p /λ 0 ) – 1 of the LSPR-wavelength for a pair, λ p , relative to that for an isolated particle, λ 0 , can be represented as a damped exponential function of the distance between surfaces of particles, s , which is measured for spheres in units of their diameters, D : ,,− ,,,,, Δ λ / λ 0 = a exp false( prefix− x / t false) where x = s / D , a and t are coefficients.…”

Section: Introductionmentioning

confidence: 97%

Nanometric Rulers Based on Plasmon Coupling in Pairs of Gold Nanoparticles

Dolinnyi

2015

J. Phys. Chem. C

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Using a generalized multiparticle Mie theory, we calculated the optical properties of gold nanoparticle (Au NP) pairs of 8−80 nm in diameter (D) and 0.1−120 nm in interparticle gap (s) under typical experimental conditions: an unpolarized incident light and random orientation of the pairs in space. By analyzing the extinction spectra of coupled spheres, three ranges of interparticle separations (long, middle and short) with different plasmon coupling regimes were distinguished. For long interparticle distances, a single plasmon peak in the spectrum at wavelength λ p red-shifts exponentially relative to that of an isolated particle at wavelength λ 0 as a function of x = s/D: Δλ/λ 0 = (λ p − λ 0 )/ λ 0 = a exp(−x/t), with a decay constant (t = 0.19) being nearly independent of nanoparticle diameters at D < 50 nm. Stronger shifts (0.04 < a < 0.08) are observed for 30−60 nm Au NPs. In the middle distance range (0.02 < s/D < (s/ D) split ), the extinction spectra of dimers have two plasmon peaks: transverse and longitudinal. The shift of long-wavelength peak can be reasonably approximated by the equation Δλ/λ 0 = a 0 + a 1 exp(−x/t 1 ), where the parameters a 1 (= 0.352) and t 1 (= 0.032) do not depend on the nanoparticle sizes, and a 0 increases with particle size. The boundary between the long and middle interparticle distance ranges, (s/D) split , strongly varies with the Au NP diameter. At s/D < 0.02, the birth and evolution of third plasmon peak that is located between the transverse and longitudinal peaks has a strong effect upon the spectral properties of closely coupled NPs. Now the fractional shift of the longitudinal peak obeys the equation Δλ/λ 0 = a 0 + a 1 exp(−x/t 1 ) + a 2 exp(−x/t 2 ), where t 2 = 0.004 and a 2 = 0.643. The constancy of coefficients a i and t i for Au NPs of different sizes means that the fractional shifts of plasmon resonances of coupled pairs corrected by parameter a 0 have to fall on a common curve. The obtained results clearly point that the Au NPs pairs can be used as the highly sensitive instruments to measure both absolute distances and their changes in the nanometric range of lengths.

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“…We previously reported a crown nanoparticle plasmon ruler that detects caspase-3 activity in vitro and in vivo through the principle of plasmon coupling, where caspase-3 cleaves a peptide substrate that links a core and satellite plasmonic particles sequentially, causing decoupling of plasmon resonance between the particles . Due to the unique properties of plasmon rulers, including assembly dependent plasmon resonance, strong optical light scattering, and extremely photostable characteristics, highly sensitive detection of caspase-3 activity in a cultured cell line was possible. ,− We envisioned use of this concept for monitoring drug-response in a more clinically relevant setting by using the CML model system. To realize this in an optimized setting, we designed a new plasmon ruler assay with distinct features from the previous crown nanoparticle plasmon ruler experiments.…”

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confidence: 99%

Sensitive and Selective Plasmon Ruler Nanosensors for Monitoring the Apoptotic Drug Response in Leukemia

et al. 2014

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Caspases are proteases involved in cell death, where caspase-3 is the chief executioner that produces an irreversible cutting event in downstream protein substrates and whose activity is desired in the management of cancer. To determine such activity in clinically relevant samples with high signal-to-noise, plasmon rulers are ideal because they are sensitively affected by their interparticle separation without ambiguity from photobleaching or blinking effects. A plasmon ruler is a noble metal nanoparticle pair, tethered in close proximity to one another via a biomolecule, that acts through dipole–dipole interactions and results in the light scattering to increase exponentially. In contrast, a sharp decrease in intensity is observed when the pair is confronted by a large interparticle distance. To align the mechanism of protease activity with building a sensor that can report a binary signal in the presence or absence of caspase-3, we present a caspase-3 selective plasmon ruler (C3SPR) composed of a pair of Zn0.4Fe2.6O4@SiO2@Au core–shell nanoparticles connected by a caspase-3 cleavage sequence. The dielectric core (Zn0.4Fe2.6O4@SiO2)-shell (Au) geometry provided a brighter scattering intensity versus solid Au nanoparticles, and the magnetic core additionally acted as a purification handle during the plasmon ruler assembly. By monitoring the decrease in light scattering intensity per plasmon ruler, we detected caspase-3 activity at single molecule resolution across a broad dynamic range. This was observed to be as low as 100 fM of recombinant material or 10 ng of total protein from cellular lysate. By thorough analyses of single molecule trajectories, we show caspase-3 activation in a drug-treated chronic myeloid leukemia (K562) cancer system as early as 4 and 8 h with greater sensitivity (2- and 4-fold, respectively) than conventional reagents. This study provides future implications for monitoring caspase-3 as a biomarker and efficacy of drugs.

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Plasmon Rulers as Dynamic Molecular Rulers in Enzymology

Cited by 10 publications

References 38 publications

Plasmons in Strongly Coupled Metallic Nanostructures

Plasmons in Strongly Coupled Metallic Nanostructures

Nanometric Rulers Based on Plasmon Coupling in Pairs of Gold Nanoparticles

Sensitive and Selective Plasmon Ruler Nanosensors for Monitoring the Apoptotic Drug Response in Leukemia

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