Label-free second harmonic and hyper Rayleigh scattering with high efficiency

Gomopoulos, Nikolaos; Lütgebaucks, Cornelis; Sun, Qinchao; Macias-Romero, Carlos; Roke, Sylvie

doi:10.1364/oe.21.000815

Cited by 55 publications

(61 citation statements)

References 40 publications

(57 reference statements)

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“…The SHG signal is dependent on the surface potential created by the electrostatic field of the surface charges, often called the χ (3) contribution to the SHG signal. The χ (3) method has been used to extract the surface charge density of charged planar surfaces and microparticle surfaces, e.g., liposomes, polymer beads, and oil droplets in water (21,25,(34)(35)(36)(37)(38)(39).…”

Section: Significancementioning

confidence: 99%

Label-free probe of HIV-1 TAT peptide binding to mimetic membranes

Rao

Kwok

Lombardi

et al. 2014

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

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The transacting activator of transduction (TAT) protein plays a key role in the progression of AIDS. Studies have shown that a +8 charged sequence of amino acids in the protein, called the TAT peptide, enables the TAT protein to penetrate cell membranes. To probe mechanisms of binding and translocation of the TAT peptide into the cell, investigators have used phospholipid liposomes as cell membrane mimics. We have used the method of surface potential sensitive second harmonic generation (SHG), which is a label-free and interface-selective method, to study the binding of TAT to anionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-1′-rac-glycerol (POPG) and neutral 1-palmitoyl-2-oleoylsn-glycero-3-phosphocholine (POPC) liposomes. It is the SHG sensitivity to the electrostatic field generated by a charged interface that enabled us to obtain the interfacial electrostatic potential. SHG together with the Poisson-Boltzmann equation yielded the dependence of the surface potential on the density of adsorbed TAT. We obtained the dissociation constants K d for TAT binding to POPC and POPG liposomes and the maximum number of TATs that can bind to a given liposome surface. For POPC K d was found to be 7.5 ± 2 μM, and for POPG K d was 29.0 ± 4.0 μM. As TAT was added to the liposome solution the POPC surface potential changed from 0 mV to +37 mV, and for POPG it changed from −57 mV to −37 mV. A numerical calculation of K d , which included all terms obtained from application of the Poisson-Boltzmann equation to the TAT liposome SHG data, was shown to be in good agreement with an approximated solution.Gouy-Chapman model | hyper-Rayleigh scattering | biomolecules/water interface | colloid/water interface | nonlinear optical spectroscopy T he HIV type 1 (HIV-1) transacting activator of transduction (TAT) is an important regulatory protein for viral gene expression (1-3). It has been established that the TAT protein has a key role in the progression of AIDS and is a potential target for anti-HIV vaccines (4). For the TAT protein to carry out its biological functions, it needs to be readily imported into the cell. Studies on the cellular internalization of TAT have led to the discovery of the TAT peptide, a highly cationic 11-aa region (protein transduction domain) of the 86-aa full-length protein that is responsible for the TAT protein translocating across phospholipid membranes (5-8). The TAT peptide is a member of a class of peptides called cell-penetrating peptides (CPPs) that have generated great interest for drug delivery applications (ref. 9 and references therein). The exact mechanism by which the TAT peptide enters cells is not fully understood, but it is likely to involve a combination of energy-independent penetration and endocytosis pathways (8, 10). The first step in the process is high-affinity binding of the peptide to phospholipids and other components on the cell surface such as proteins and glycosaminoglycans (1, 9).The binding of the TAT peptide to liposomes has been investigated using a variety of techniques, each...

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Section: Significancementioning

confidence: 99%

Label-free probe of HIV-1 TAT peptide binding to mimetic membranes

Rao

Kwok

Lombardi

et al. 2014

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

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“…16 Our group, 17,18,19 along with others, 20,21,22,23,24 has demonstrated that SHS is capable of probing the surface of nanometer size particles in the colloidal environment. In particular, we have shown that the surface of metallic nanoparticles (NPs) can be examined.…”

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confidence: 99%

Adsorption of Anionic Thiols on Silver Nanoparticles

Gonella

DeLacy

et al. 2015

J. Phys. Chem. C

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The adsorption of negatively charged 3-mercaptopropanesulfonate (MPS) on the surface of citrate-stabilized Ag nanoparticles in water is investigated using colloidal particle surface sensitive techniques. The adsorption of this negatively charged thiol appears to be qualitatively different from that of neutral thiols, and highlights the importance of repulsive interactions of electrostatic and steric origins pertaining to charged thiols. For the charged MPS thiol, the adsorption process occurs in two phases. At low surface coverage, where the intermolecular repulsion is negligible and the adsorption is dominated by the formation of the S−Ag bond, MPS molecules need to overcome an activation energy barrier =(7.5±0.9) kcal/mol with an associated free energy change =-(14.3±0.3) kcal/mol, and behave similar to neutral thiols. On the other hand, at high surface coverage where the repulsive interactions among MPS molecules cannot be neglected, the adsorption is characterized by a higher = (12.4±0.5) kcal/mol and lower =-(7.4±0.1) kcal/mol.

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“…The generated SHG reflection was passed through a blue filter (BG39) and a band-pass filter (FB400-10) to filter the fundamental frequency, and, subsequently, a polarizer was used to select the p - and s -polarization for Ag and Ni samples, respectively. To account for the hyper-Rayleigh scattering (HRS) [37,38], the reflected SHG light was collected through a focusing lens with a large numerical aperture. Here, HRS is incoherent second-harmonic (SH) scattering from small feature structures based on Mie theory; up to now, HRS signals from spherical and non-spherical lacking centrosymmetric structures have been observed [39,40].…”

Section: Methodsmentioning

confidence: 99%

“…Here, HRS is incoherent second-harmonic (SH) scattering from small feature structures based on Mie theory; up to now, HRS signals from spherical and non-spherical lacking centrosymmetric structures have been observed [39,40]. Hence, the consideration of HRS is important, and the experimental setup has been referred to in some papers [38,41]. Following polarization selection, the reflected SHG light signals were detected by a photomultiplier tube (PMT).…”

Section: Methodsmentioning

confidence: 99%

Nonlinear optics on nano/micro-hierarchical structures on metals: focus on symmetric and plasmonic effects

Ogata

Guo

2017

Nano Reviews & Experiments

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In this review, the authors study their creation of nano/micro-hierarchical structures on Ag and Ni substrates by femtosecond laser treatment and their investigation of their optical second-harmonic generation (SHG) signal intensities by SHG spectroscopy. The authors obtained the nanostructure-covered microgroove and microcube structures. These hierarchical surface structures were found to modify significantly the optical nonlinearity of the metal surfaces. The macroscopic symmetry of the surface’s shapes influenced SHG, and the excitation of surface plasmons enhanced SHG. On the other hand, the nanostructures on the microstructures had an additional effect on the generated SHG. For the microcube structures, the additional SHG emission was suppressed by removing a large amount of nanostructures. Left SHG was discussed by the effect of the propagating delay.

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Label-free second harmonic and hyper Rayleigh scattering with high efficiency

Cited by 55 publications

References 40 publications

Label-free probe of HIV-1 TAT peptide binding to mimetic membranes

Label-free probe of HIV-1 TAT peptide binding to mimetic membranes

Adsorption of Anionic Thiols on Silver Nanoparticles

Nonlinear optics on nano/micro-hierarchical structures on metals: focus on symmetric and plasmonic effects

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