Probing the colloidal gold nanoparticle/aqueous interface with second harmonic generation

Haber, Louis H.; Kwok, Sheldon J. J.; Semeraro, Monica; Eisenthal, Kenneth B.

doi:10.1016/j.cplett.2011.03.042

Cited by 65 publications

(81 citation statements)

References 45 publications

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“…21,25 Briefly, the setup consists of an ultrafast laser system, an optical setup, and a high-sensitivity charge-coupled device spectroscopy detector connected to a monochromator-spectrograph. A titanium:sapphire oscillator laser with 2.6 W average power and 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 7 70 fs pulses centered at 800 nm with a repetition rate of 80 MHz is attenuated to 1.2 W and is focused to the gold nanoparticle sample at an initial concentration of 4.4 x 10 9 nanoparticles per mL in a 1 cm quartz cuvette.…”

Section: Methodsmentioning

confidence: 99%

“…3 Second harmonic generation (SHG) is a powerful, noninvasive, surface-sensitive technique that is useful for the investigation of colloidal nanoparticles. 21,[23][24][25][26][27][28] SHG is a nonlinear optical process in which two incident photons of frequency ω add coherently to generate a photon of frequency 2ω. [29][30][31] SHG is typically forbidden in bulk media that have inversion symmetry but it can be generated at the surface of nanoparticles where the inversion symmetry is broken.…”

Section: Introductionmentioning

confidence: 99%

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Determination of the Surface Charge Density of Colloidal Gold Nanoparticles Using Second Harmonic Generation

2015

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Second harmonic generation is used to investigate the surface charge density of 50 nm colloidal gold nanoparticles in water. The gold nanoparticles are thiolated with mercaptosuccinic acid and are dialyzed in ultrapure water to remove excess salts and reactants. The second harmonic generation signal from the nanoparticle sample is measured as a function of added sodium chloride and magnesium chloride salt concentrations using the χ (3) technique. The experimental results are fit to the Gouy-Chapman model and to numerical solutions to the spherical PoissonBoltzmann equation that account for the nanoparticle surface curvature, the different salt valences, and ion adsorption to the Stern layer interface. The best fits use the numerical solutions including ion adsorption and determine the initial surface charge density to be −2.0 ± 0.1 x 10 −3 C/m 2 at the gold nanoparticle surface, in agreement with electrophoretic mobility measurements.In addition, the sodium ion is observed to adsorb with a higher surface charge density than the magnesium ion. These results demonstrate the important effects of surface curvature and ion adsorption in describing the surface chemistry and surface charge density of colloidal gold nanoparticles in water.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Determination of the Surface Charge Density of Colloidal Gold Nanoparticles Using Second Harmonic Generation

2015

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“…The experimental apparatus used to measure the time-resolved SH signal is similar to those described in previous reports (34,36) with the addition of a Princeton Instruments CCD camera. The fundamental laser frequency was centered at 810 nm with approximately 400 mW of average power and a pulse width of approximately 75 fs.…”

Section: Methodsmentioning

confidence: 99%

Binding and cleavage of DNA with the restriction enzyme EcoR1 using time-resolved second harmonic generation

Doughty

Kazer

Eisenthal

2011

Proc. Natl. Acad. Sci. U.S.A.

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The binding of EcoR1 to a 90-bp DNA duplex attached to colloidal microparticles and the subsequent cleavage by the enzyme was observed in real time and label-free with time-resolved second harmonic (SH) spectroscopy. This method provides a unique way to investigate biomolecular interactions based on its sensitivity to changes in structure and electrical charge on formation of a complex and subsequent dynamics. The binding of EcoR1 to the recognition sequence in DNA appears as a rapid increase in the SH signal, which is attributed to the enzyme-induced change in the DNA conformation, going from a rod-like to a bent shape. In the presence of the cofactor Mg 2 , the subsequent decay in the SH signal was monitored in real time as the following processes occurred: cleavage of DNA, dissociation of the enzyme from the DNA, and diffusion of the 74-bp fragment into the bulk solution leaving the 16-bp fragment attached to the microparticle. The observed decay was dependent on the concentration of Mg 2 , which functions as a cofactor and as an electrolyte. With SH spectroscopy the rehybridization dynamics between the rehybridized microparticle bound and free cleaved DNA fragments was observed in real time and label-free following the cleavage of DNA. Collectively, the experiments reported here establish SH spectroscopy as a powerful method to investigate equilibrium and time-dependent biological processes in a noninvasive and label-free way.cleavage kinetics | DNA-endonuclease | rehybridization kinetics | nonspecific binding T he highly selective binding of proteins to specific nucleotide sequences in DNA is an essential step in many biological processes, including gene regulation, gene expression, and DNA hybridization (1). The family of type II restriction enzymes, which includes EcoR1, have been, and continue to be, of major importance in serving as model systems of protein-DNA interactions. The endonucleases, because of their capability to bind and cleave specific DNA sequences, also play a key role in DNA recombinant and cloning methods (1, 2). The EcoR1-DNA equilibria and reaction dynamics have been probed extensively by a number of established methods, such as, but not limited to: FRET (3-5), gel electrophoresis (6-15), surface plasmon resonance (16), microfluidic trapping (17), two-color cross-correlation spectroscopy (18), and isothermal calorimetry (19).The essential characteristic of the method used here is the application of second harmonic (SH) spectroscopy to selectively probe the interface of a polystyrene carboxylate (PSC) microparticle, to which target DNA molecules have been attached. Significant effort and progress has been made in hybridizing artificial colloidal nano-and micromaterials with naturally occurring biological reagents to build self-assembled superstructured materials (20-26), and to develop biologically coded probes for protein detection and disease treatment (27,28). The present work builds on these pioneering studies, and on studies of DNA supported on flat surfaces using SH and sum-frequ...

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“…For centrosymmetric materials SH is generated at the surface of nano-particles, because symmetry is broken at that interface as Wang has demonstrated experimentally for the first time [2]. SHG has been applied to study the surface and buried micro-structure of colloidal nano-particles [3][4][5][6][7][8][9][10][11][12][13] or as probing technique in bio-physical experiments [14][15][16][17][18]. We have used SHG to determine the nonlinear susceptibility ( ) 2 χ of a thin layer of Malachite Green [19], to study the layer of oriented water near polystyrene particles [20] and the organization of polyelectrolyte chains, depending on the salt concentration of the solvent [21].…”

Section: Introductionmentioning

confidence: 99%

Plasmonic enhancement of second harmonic generation on metal coated nanoparticles

Wunderlich¹,

Peschel²

2013

Opt. Express

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Second Harmonic Generation (SHG) is a widely used tool to study surfaces. Here we investigate SHG from spherical nanoparticles consisting of a dielectric core (radius 100 nm) and a metallic shell of variable thickness. Plasmonic resonances occur that depend on the thickness of the nanoshells and boost the intensity of the Second Harmonic (SH) signal. The origin of the resonances is studied for the fundamental harmonic and the second harmonic frequencies. Mie resonances at the fundamental harmonic frequency dominate resonant effects of the SHsignal at low shell thickness. Resonances excited by a dipole emitting at SH frequency close to the surface explain the enhancement of the SHG-process at a larger shell thickness. All resonances are caused by surface plasmon polaritons, which run on the surface of the spherical particle and are in resonance with the circumference of the sphere. Because their wavelength critically depends on the properties of the metallic layer SHG resonances of core-shell nanoparticles can be easily tuned by varying the thickness of the shell. References and links1. Y. Shen, "Surface 2nd harmonic-generation -a new technique for surface studies," Annu. Rev. Mater. Sci. 16(1), 69-86 (1986). 2. H. Wang, E. C. Y. Yan, E. Borguet, and K. B. Eisenthal, "Second harmonic generation from the surface of centrosymmetric particles in bulk solution," Chem. Phys. Lett. 259(1-2), 15-20 (1996). 3. E. C. Y. Yan, Y. Liu, and K. B. Eisenthal, "New method for determination of surface potential of microscopic particles by second harmonic generation," J. Chem. Phys. B 102(33), 6331-6336 (1998 11-14 (2011). 14. J. Griffin, A. K. Singh, D. Senapati, E. Lee, K. Gaylor, J. Jones-Boone, and P. C. Ray, "Sequence-Specific HCV RNA Quantification Using the Size-Dependent Nonlinear Optical Properties of Gold Nanoparticles," Small 5 (

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Probing the colloidal gold nanoparticle/aqueous interface with second harmonic generation

Cited by 65 publications

References 45 publications

Determination of the Surface Charge Density of Colloidal Gold Nanoparticles Using Second Harmonic Generation

Determination of the Surface Charge Density of Colloidal Gold Nanoparticles Using Second Harmonic Generation

Binding and cleavage of DNA with the restriction enzyme EcoR1 using time-resolved second harmonic generation

Plasmonic enhancement of second harmonic generation on metal coated nanoparticles

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