Inclusion complexes of cysteinyl ß-cyclodextrin with baicalein restore collagen synthesis in fibroblast cells following ultraviolet exposure.

Baicalein, a bioactive flavonoid, has poor water solubility, thereby limiting its use in a wide range of biological applications. In the present study, we used inclusion complexes of cysteinyl ß-cyclodextrin (ß-CD) with baicalein to enhance the stability and solubility of baicalein in aqueous solution. We examined the effects of inclusion complexes of cysteinyl ß-CD on collagen synthesis following ultraviolet (UV) irradiation, as well as the mechanisms underlying its effects. Our findings demonstrated that baicalein significantly restored collagen synthesis in the UV-exposed human fibroblast Hs68 cells. In addition, synthetic cysteine functionalized ß-CDs were found to promote baicalein-induced collagen synthesis. Inclusion complexes of cysteinyl ß-CDs with baicalein significantly upregulated the protein expression of type I collagen and activated the transcription of type I, II, and III collagen. Inclusion complexes of cysteinyl ß-CDs with baicalein also downregulated matrix metalloproteinase -1 and -3, and α-smooth muscle actin expression. In addition, inclusion complexes of cysteinyl ß-CDs with baicalein attenuated the expression of caveolin-1, but this treatment enhanced the UV-induced phosphorylation of Smad in the transforming growth factor-ß pathway. These results suggested that the newly synthesized derivative of CD can be used as a complexing agent to enhance the bioavailability of flavonoids such as baicalein, especially in restoring collagen synthesis.

Hyperspectral depth-profiling with deep Raman spectroscopy for detecting chemicals in building materials.

Toxic chemicals inside building materials have long-term harmful effects on human bodies. To prevent secondary damage caused by the evaporation of latent chemicals, it is necessary to detect the chemicals inside building materials at an early stage. Deep Raman spectroscopy is a potential candidate for on-site detection because it can provide molecular information about subsurface components. However, it is very difficult to spectrally distinguish the Raman signal of the internal chemicals from the background signal of the surrounding materials and to acquire the geometric information of chemicals. In this study, we developed hyperspectral wide-depth spatially offset Raman spectroscopy coupled with a data processing algorithm to identify toxic chemicals, such as chemical warfare agent (CWA) simulants in building materials. Furthermore, the spatial distribution of the chemicals and the thickness of the building material were also measured from one-dimensional (1D) spectral variation.

2-[5-(2,3-Di-meth-oxy-naphthalen-1-yl)-4,5-di-hydro-1H-pyrazol-3-yl]-3-meth-oxy-phenol.

In the title compound, C22H22N2O4, the central pyrazoline ring exhibits a nearly planar structure (r.m.s. deviation = 0.025 Å) despite having two sp 3 carbon atoms. The pyrazoline ring subtends dihedral angles of 4.61 (1) and 87.31 (1)° with the pendant benzene ring and naphthalene ring system, respectively. The dihedral angle between the planes of the benzene ring and the naphthalene ring system is 89.76 (2)°. An intra-molecular O-H⋯N hydrogen bond forms an S(6) ring motif. In the crystal, inversion dimers formed by pairwise weak N-H⋯N hydrogen bonds generate R 2 2(4) loops and the dimers are linked by pairwise C-H⋯O hydrogen bonds [which generate R 2 2(8) loops] into [100] chains.

3-(2,3-Di-meth-oxy-phen-yl)-2,3-di-hydro-1H-benzo[f]chromen-1-one.

In the title compound, C21H18O4, the central pyran ring is in an envelope conformation and the dihedral angle between the benzene ring and naphthalene ring system is 88.31 (1)°. The meth-oxy groups at the ortho and meta positions of the benzene ring are tilted to the ring with C-C-O-C torsion angles of 105.9 (4) and 9.5 (5)°, respectively. In the crystal, pairwise C-H⋯O hydrogen bonds form R 2 2(14) inversion dimers, which are linked by another pair of C-H⋯O hydrogen bonds to form [210] chains in the crystal.

Ethyl 2-[(E)-({2,4-dimeth-oxy-6-[2-(4-meth-oxy-phen-yl)ethen-yl]benzyl-idene}amino)-oxy]acetate.

In the title compound, C22H25NO6, the C=C double bond linking the benzene rings adopts an E configuration and the dihedral angle between the rings is 47.1 (2)°. The oxime unit contains a C=N double bond, which also has an E configuration. In the crystal, pairs of C-H⋯N hydrogen bonds generate inversion dimers and weak C-H⋯O inter-actions link the dimers into chains propagating along the b-axis direction.

3-(2-Meth-oxy-phen-yl)-2,3-di-hydro-1H-benzo[f]chromen-1-one.

In the title compound, C20H16O3, the 2-meth-oxy-phenyl ring is tilted by 50.67 (3)° with respect to the naphthyl ring system. The central pyran ring has an envelope conformation with the C atom bearing the pendant ring system as the flap. The meth-oxy group attached to the benzene ring is slightly twisted [C-C-O-C = -15.2 (1)°] from the ring. In the crystal, weak C-H⋯O inter-actions link the mol-ecules into C(7) chains propagating along [101].

Combination of Mass Signal Amplification and Isotope-Labeled Alkanethiols for the Multiplexed Detection of miRNAs.

We report a fast and sensitive method for the multiplexed detection of miRNAs by combining mass signal amplification and isotope-labeled signal reporter molecules. In our strategy, target miRNAs are captured specifically by immobilized DNAs on gold nanoparticles (AuNPs), which carry a large number of small molecules, called amplification tags (Am-tags), as the reporter for the detection of target miRNAs. For multiplexed detection, we designed and synthesized four Am-tags containing 0, 4, 8, 12 isotopes so that they had same molecular properties but different molecular weights. By observing the mass signals of the Am-tags on AuNPs decorated along with different probe DNAs, four types of miRNAs in a sample could be easily discriminated, and the relative amounts of these miRNAs could be quantified. The practicability of our strategy was further verified by measuring the expression levels of two miRNAs in HUVECs in response to different CuSO4 concentrations.

Zinc Ion-immobilized Magnetic Microspheres for Enrichment and Identification of Multi-phosphorylated Peptides by Mass Spectrometry.

The selective isolation of phosphorylated peptides and subsequent analysis using mass spectrometry is important for understanding how protein kinase and phosphatase signals can precisely modulate the on/off states of signal transduction pathways. However, the isolation and detection of multi-phosphorylated peptides is still limited due to their distinct affinity to various materials and their poor ionization efficiency. Here, we report a highly efficient and selective enrichment of phosphorylated peptides using binuclear Zn2+-dipicolylamine complex-coated magnetic microspheres (ZnMMs). ZnMMs can utilize the rapid and selective isolation/enrichment of phosphorylated peptides and the subsequent mass spectrometric analysis, given the intrinsic magnetic property of magnetic microspheres and the highly selective binding ability of the binuclear Zn2+-dipicolylamine complex to phosphate groups. α-Casein and ß-casein were chosen for a proof-of-concept demonstration. We contemplated that phosphopeptides were selectively isolated and enriched from both the tryptic digests of casein proteins and mixed samples with a high degree of sensitivity by facilitating ZnMMs. Especially, ZnMMs showed high efficiency with multi-phosphopeptides, which are in general difficult to be examined by mass analysis on account of their poor ionization efficiency. For the model protein α, ß-casein mixture of the tryptic digest, 17 phosphopeptides were identified with ZnMMs and 82% of the enriched phosphopeptides were multi-phosphorylated peptides, indicating that ZnMMs have excellent enrichment efficiency and strong affinity towards multi-phosphorylated peptides.

Second harmonic excitation spectroscopy of silver nanoparticle arrays.

Frequency-scanned excitation profiles of coherent second harmonic generation (SHG) were measured for silver nanoparticle arrays prepared by nanosphere lithography. The frequency of the fundamental beam did not coincide with the localized surface plasmon resonance (LSPR) of the nanoparticles and was tuned so that the coherent second harmonic (SH) emission was in the region of the LSPR at 720-750 nm. The SH emission from the arrays was compared with a smooth silver film to identify an enhancement of SH emission efficiency that peaks near approximately 650 nm for nanoparticles 50 nm in height. The polarization and orientation dependence of this enhancement suggests that it is related to a dipolar LSPR mode polarized normal to the plane of the substrate. Linear extinction spectra are dominated by in-plane dipoles and do not show this weak out-of-plane LSPR mode. The nanoparticle arrays are truncated tetrahedrons symmetrically oriented by nanosphere lithography to cancel SH from in-plane dipoles which allows observation of the weak out-of-plane component.

Chemical imaging and microspectroscopy with spectral focusing coherent anti-Stokes Raman scattering.

We demonstrate two different coherent anti-Stokes Raman scattering (CARS) microscopy and microspectroscopy methods based on the spectral focusing mechanism. The first method uses strongly chirped broadband pulses from a single Ti:sapphire laser and generates CARS signals at the fingerprint region. Fast modulation of the time delay between the pump and Stokes laser pulses coupled with lock-in signal detection significantly reduces the nonresonant background and produces Raman-like CARS signals with a spectral resolution of 20 cm(-1). The second method generates CARS signals in the CH (carbon-hydrogen) stretching region with IR supercontinuum pulses from a photonic crystal fiber. The spectral resolution of 30 cm(-1) is achieved. Maximum entropy method is used to retrieve a Raman-equivalent CARS spectrum from lipid membranes. Chemical imaging and microspectroscopy are demonstrated with various samples.

Chemical imaging with frequency modulation coherent anti-Stokes Raman scattering microscopy at the vibrational fingerprint region.

We present a new coherent anti-Stokes Raman scattering (CARS) method that can perform background-free microscopy and microspectroscopy at the vibrational fingerprint region. Chirped broad-band pulses from a single Ti:sapphire laser generate CARS signals over 800-1700 cm(-1) with a spectral resolution of 20 cm(-1). Fast modulation of the time delay between the pump and Stokes pulses coupled with lock-in signal detection not only removes the nonresonant background but also produces Raman-like CARS signals. Chemical imaging and microspectroscopy are demonstrated with various samples such as edible oils, lipid membranes, skin tissue, and plant cell walls. Systematic studies of the signal generation mechanism and several fundamental aspects are discussed.

Single-beam homodyne SPIDER for multiphoton microscopy.

We report a new version of spectral phase interferometry for direct electric field reconstruction (SPIDER) requiring only a single phase-shaped laser beam. A narrowband probe pulse is selected out of a broadband ultrafast laser pulse by a phase pulse-shaping technique and mixed with the original broadband pulse to generate a second-harmonic generation (SHG) signal. Using another SHG signal solely generated by the broadband pulse as a local oscillator, the spectral phase of the broadband laser pulse can be analytically retrieved by a combination of double-quadrature spectral interferometry and homodyne optical technique for SPIDER (HOT SPIDER). An arbitrary spectral phase at the sample position of a microscope can be compensated with a precision of 0.05 rad over the FWHM of the laser spectrum. It is readily applicable to a nonlinear microscopy technique with a phase-controlled broadband laser pulse.

Spectroscopic observation of conformation-dependent charge distribution in a molecular cation.

A prototypical case of a molecular radical cation is reported whose electrostatic charge distribution is determined entirely and uniquely by its conformational structures. Experimental observation of charge distribution in a molecular ion was for the first time demonstrated to be feasible by optical spectroscopy in the case of L-phenylalanine cation by utilizing the fact that its photodissociation propensity is entirely determined by the electronic character of its charge distribution. The cationic charge was explicitly shown to be localized in a single site or two different sites depending on the molecular conformation.

Interaction of plasmon and molecular resonances for rhodamine 6G adsorbed on silver nanoparticles.

Localized surface plasmon resonance (LSPR) is a key optical property of metallic nanoparticles. The peak position of the LSPR for noble-metal nanoparticles is highly dependent upon the refractive index of the surrounding media and has therefore been used for chemical and biological sensing. In this work, we explore the influence of resonant adsorbates on the LSPR of bare Ag nanoparticles (lambda(max,bare)). Specifically, we study the effect of rhodamine 6G (R6G) adsorption on the nanoparticle plasmon resonance because of its importance in single-molecule surface-enhanced Raman spectroscopy (SMSERS). Understanding the coupling between the R6G molecular resonances and the nanoparticle plasmon resonances will provide further insights into the role of LSPR and molecular resonance in SMSERS. By tuning lambda(max,bare) through the visible wavelength region, the wavelength-dependent LSPR response of the Ag nanoparticles to R6G binding was monitored. Furthermore, the electronic transitions of R6G on Ag surface were studied by measuring the surface absorption spectrum of R6G on an Ag film. Surprisingly, three LSPR shift maxima are found, whereas the R6G absorption spectrum shows only two absorption features. Deconvolution of the R6G surface absorption spectra at different R6G concentrations indicates that R6G forms dimers on the metal surface. An electromagnetic model based on quasi-static (Gans) theory reveals that the LSPR shift features are associated with the absorption of R6G monomer and dimers. Electronic structure calculations of R6G under various conditions were performed to study the origin of the LSPR shift features. These calculations support the view that the R6G dimer formation is the most plausible cause for the complicated LSPR response. These findings show the extreme sensitivity of LSPR in elucidating the detailed electronic structure of a resonant adsorbate.

Comparative study of charge division in substituted benzene cations.

A recently proposed phenomenon of charge division in a molecular cation [K. T. Lee et al., J. Am. Chem. Soc. 129, 2588 (2007)] was examined in a number of molecules by experiment and theory. We investigated the spatial distribution of electrostatic charge in the cation of the following benzene derivatives: n-propylbenzene (PB), 3-phenylpropionic acid (PPA), 2-phenylethyl alcohol (PEAL), and 2-phenylethylamine (PEA). A density functional theory calculation indicated that the positive charge was divided into two cationic charge cores in both conformers of PEA+, while it is localized mainly on the phenyl group in PB+, PPA+, and PEAL+. This finding was experimentally verified by the characteristic range of electronic transition of these species reflected in the fragmentation pattern of the mass spectra. The degree of charge division in PEA+ was slightly less than in the cationic conformers of L-phenylalanine in its subgroup II. The charge distribution in a phenyl-containing cation is suggested to depend on whether there exists a functional group that can act as a competing charge core against the phenyl ring.

Ultrafast electron-transfer and solvent adiabaticity effects in viologen charge-transfer complexes.

We report ultrafast electron transfer (ET) in charge-transfer complexes that shows solvent relaxation effects consistent with adiabatic crossover models of nonadiabatic ET. The complexes of either dimethyl viologen (MV) or diheptyl viologen (HV) with 4,4'-biphenol (BP) (MVBP or HVBP complexes) have identical charge-transfer spectra and kinetics in ethylene glycol with approximately 900 fs ET decay. We assign this decay time as largely due to adiabatic control of a predicted approximately 40 fs nonadiabatic ET. The MVBP decay in methanol of 470 fs is reduced in mixtures having low (2-20%) concentrations of acetonitrile to as short as 330 fs; these effects are associated with faster relaxation time in methanol and its mixtures. In contrast, HVBP has much longer ET decay in methanol (730 fs) and mixture effects that only reduce its decay to 550 fs. We identify the heptyl substituent as creating major perturbations to solvent relaxation times in the methanol solvation shell of HVBP. These charge-transfer systems have reasonably well-defined geometry with weak electronic coupling where the electronic transitions are not dependent on intramolecular motions. We used a nonadiabatic ET model with several models for adiabatic crossover predictions to discuss the small variation of energy gap with solvent and the ET rates derived from adiabatic solvent control. A time correlation model of solvent relaxation was used to define the solvent relaxation times for this case of approximately zero-barrier ET.