Structural Studies of Amphiphilic 4-Helix Bundle Peptides Incorporating Designed Extended Chromophores for Nonlinear Optical Biomolecular Materials

Strzalka, Joseph; Xu, Ting; Tronin, Andrey; Wu, Sophia P.; Miloradovic, Ivan; Kuzmenko, Ivan; Gög, T.; Therien, Michael J.; Blasie, J. Kent

doi:10.1021/nl062092h

Cited by 29 publications

(58 citation statements)

References 25 publications

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“…By using b w = 0.56 10 À30 esu, as reported in the literature, we have found out b nano = 3.8 10 À24 esu for 80 nm gold nanorod and 4.2 10 À24 esu for DNA adsorbed gold nanorod, which is about 3-4 orders of magnitude higher than the b values reported for the best available molecular chromophores [21][22][23][24][25][26][27]37] and 1-2 orders of magnitude higher than the b value reported for gold nanoparticles. [6,22,38,39] This higher b value for nanorods with respect to nanosphere can be due to several facts and these are 1) The presence of {110} facets, which is not present in nanospheres, is known to give rise to strong absorption energies; 2) the surface electromagnetic field of rods is the highest relative to other shapes due to the rods high curvatures (called "the lightning rod" effect [40] ); 3) the presence of multipoles; and 4) possibility of single-photon resonance enhancement.…”

Section: Resultssupporting

confidence: 49%

“…The technique can be easily applied to study a very wide range of materials, because electrostatic fields and phase matching are not required. [6,[21][22][23][24][25][26][37][38][39][40] Other advantages are that the polarization analysis gives information about the tensor properties, and spectral analysis of the scattered light gives information about the dynamics. We monitored the second-order NLO properties using the HRS technique.…”

Section: Preparation Of Dna Gold Nanorod Conjugatesmentioning

confidence: 99%

“…Diagnosis of an oligonucleotide sequence by using unmodified DNA remains attractive due to the simple sample preparation, low DNA assay cost, and the elimination of potential artifacts from modification. Driven by the need, we demonstrate for the first time that second-order nonlinear optical (NLO) properties [21][22][23][24][25][26][27] of gold nanorods can be used for screening HIV DNA without any modification, with excellent sensitivity (100 pm) and selectivity (single base-pair mismatch).…”

Section: Introductionmentioning

confidence: 99%

“…NLO properties have been monitored by using the hyperRayleigh scattering (HRS) technique. [6,[21][22][23][24][25][26][27] Using these enhanced, sensitive, and tunable optical scattering properties, we have shown that with the HRS technique, [6,[21][22][23][24][25][26][27] which has emerged over the past decade as a powerful method to determine the microscopic nonlinear optical (NLO) properties of species in solution, we can achieve detection of HIV DNA with excellent sensitivity (100 pm) and selectivity (single base-pair mismatch).…”

Section: Introductionmentioning

confidence: 99%

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Gold‐Nanorod‐Based Sensing of Sequence Specific HIV‐1 Virus DNA by Using Hyper‐Rayleigh Scattering Spectroscopy

Darbha

Shanker

Singh

et al. 2008

Chemistry A European J

111

166

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Infectious diseases caused by the human immunodeficiency virus (HIV) remain the leading killers of human beings worldwide, and function to destabilize societies in Africa, Asia, and the Middle East. Driven by the need to detect the presence of HIV viral sequence, here we demonstrate that the second-order nonlinear optical (NLO) properties of gold nanorods can be used for screening HIV-1 viral DNA sequence without any modification, with good sensitivity (100 pico-molar) and selectivity (single base-pair mismatch). The hyper-Rayleigh scattering (HRS) intensity increases 45 times when a label-free 145-mer, ss-gag gene DNA, was hybridized with 100 pM target DNA. The mechanism of HRS intensity change has been discussed with experimental evidence for higher multipolar contribution to the NLO response of gold nanorods.

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Section: Resultssupporting

confidence: 49%

Section: Preparation Of Dna Gold Nanorod Conjugatesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Gold‐Nanorod‐Based Sensing of Sequence Specific HIV‐1 Virus DNA by Using Hyper‐Rayleigh Scattering Spectroscopy

Darbha

Shanker

Singh

et al. 2008

Chemistry A European J

111

166

View full text Add to dashboard Cite

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“…[31][32][33] In this report, we examine the macroscopic ordering, packing, and nonlinear polarizability of an archetypal member of the MPZn chromophore family, ruthenium(II) [5-(4′-ethynyl-(2,2′;6′,2′′-terpyridinyl))-10,20-bis(phenyl)porphinato]-zinc(II)-(2,2′;6′,2′′-terpyridine) 2+ (RuPZn) 7 bound within the amphiphilic AP0 peptide (Scheme 1). The amphiphilicity of AP0 enables the vectorial orientation of the RuPZn-AP0 complex in macroscopic ensembles at the water-gas interface, with the long axis of the bundle perpendicular to the interface when high surface pressures are applied.…”

Section: Introductionmentioning

confidence: 99%

Control of the Orientational Order and Nonlinear Optical Response of the “Push−Pull” Chromophore RuPZn via Specific Incorporation into Densely Packed Monolayer Ensembles of an Amphiphilic 4-Helix Bundle Peptide: Second Harmonic Generation at High Chromophore Densities

et al. 2010

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The macroscopic nonlinear optical response of the "push-pull" chromophore RuPZn incorporated into a single monolayer of the amphiphilic 4-helix bundle peptide (AP0) covalently attached to a solid substrate at high in-plane density has been measured. The second-order susceptibility, chi(zzz), was found to be in the range of approximately 15 x 10(-9) esu, consistent with a coherent sum of the nonlinear contributions from the individual chromophores (beta) as previously measured in isotropic solution through hyper-Rayleigh scattering as well as estimated from theoretical calculations. The microscopic hyperpolarizability of the RuPZn chromophore is preserved upon incorporation into the peptide monolayer, suggesting that the chromophore-chromophore interactions in the densely packed ensemble do not substantially affect the first-order molecular hyperpolarizability. The polarization angle dependence of the second harmonic signal reveals that the chromophore is vectorially oriented in the two-dimensional ensemble. Analysis of the order parameter together with information obtained from grazing incidence X-ray diffraction help in determining the chromophore orientation within the AP0-RuPZn monolayer. Taking into account an average pitch angle of approximately 20 degrees characterizing the coiled-coil structure of the peptide bundle, the width of the bundle's tilt angle distribution should be sigma < or = 20 degrees, resulting in a mean value of the tilt angle 23 degrees < or = theta(0) < or = 37 degrees.

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X ‐Ray Diffraction and Spectroscopic Techniques for Liquid Surfaces and Interfaces

Vaknin

2012

Characterization of Materials

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X‐ray and neutron scattering techniques are probably the most effective tools when it comes to determining the structure of liquid interfaces on molecular‐length scales. These techniques are, in principle, not different from conventional x‐ray diffraction techniques that are commonly applied to three‐dimensional crystals, liquids, solid surfaces etc. However, special diffractometers and spectrometers that enable scattering from fixed horizontal surfaces are required to carry out the experiments. Indeed, systematic studies of liquid surfaces had not begun until the introduction of a dedicated liquid surface reflectometer. A basic property of a liquid‐vapor interface is the length scale over which the molecular density changes from the bulk value to that of the homogeneous gaseous medium. Inter molecular correlation and capillary waves, which depend on surface tension, gravity, and resolution that determines the length scale over which these correlations averaged, are among the most important factors that define the density profile across the interface and the planar correlations. In some instances the topmost layers of liquids are packed differently than in the bulk, giving rise to layering phenomena at the interface. Monolayers of compounds different than the liquid can be spread at the gas‐liquid interface (generally referred to as Langmuir monolayers). The spread compound might “wet” the liquid surface forming a film of homogeneous thickness or cluster to form an inhomogeneous rough surface. Two major diffraction techniques, complimenting one another, are used to determine interfacial structure. One is the x‐ray reflectivity (XR) technique which allows one to determine the electron density across such interfaces, from which the molecular density and the total thickness can be extracted. The other is the grazing angle x‐ray diffraction (GIXD) technique which is commonly used to obtain lateral arrangements and correlations of the topmost layers at interfaces. GIXD is especially efficient in cases where surface crystallization of the liquid or spread monolayers occurs. GIXD has been expanded to small angles (SA‐GIXD, or GI‐SAXS) for probing the structure of more complicated macromolecular systems, such as membrane proteins, and polymers. Diffuse x‐ray scattering (DXS) near the reflectivity line, which fall into the general GIXD category, are commonly to evaluate interfacial correlations, due to interfacial capillary waves, for instance. Both, XR and GIXD techniques provide structural information that is averaged over macroscopic areas, in contrast to scanning probe microscopies (SPMs), where local arrangements are probed. For an inhomogeneous interface, the reflectivity is an incoherent sum of reflectivities, accompanied by strong diffuse scattering, which, in general, is difficult to interpret definitively and often requires complementary techniques to support the x‐ray analysis. Therefore, whenever the objective of the experiment is not compromised, preparation of well‐defined homogeneous interfaces is a key to a more definitive and straightforward interpretation. The X‐ray fluorescence spectroscopy technique near total reflection from ion‐enriched liquid interfaces were developed at the same time as the diffraction techniques adding insight into ion adsorption and phenomena at liquid interfaces. The facile tunablility of photon energy at synchrotron x‐ray facilities enabled the extension of the fluorescence technique to obtain the near‐resonance surface x‐ray absorption spectroscopy (XANES) of specific interfacial ions. Photon energy tunability also facilitated the application of anomalous diffraction and spectroscopic methods commonly used for bulk materials. Anomalous XR, near edge energy scans at fixed momentum transfers have been implemented and used to determine ion distributions and ionic coordination at charged Langmuir monolayers and liquid‐liquid interfaces.

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Structural Studies of Amphiphilic 4-Helix Bundle Peptides Incorporating Designed Extended Chromophores for Nonlinear Optical Biomolecular Materials

Cited by 29 publications

References 25 publications

Gold‐Nanorod‐Based Sensing of Sequence Specific HIV‐1 Virus DNA by Using Hyper‐Rayleigh Scattering Spectroscopy

Gold‐Nanorod‐Based Sensing of Sequence Specific HIV‐1 Virus DNA by Using Hyper‐Rayleigh Scattering Spectroscopy

Control of the Orientational Order and Nonlinear Optical Response of the “Push−Pull” Chromophore RuPZn via Specific Incorporation into Densely Packed Monolayer Ensembles of an Amphiphilic 4-Helix Bundle Peptide: Second Harmonic Generation at High Chromophore Densities

X ‐Ray Diffraction and Spectroscopic Techniques for Liquid Surfaces and Interfaces

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