Pullulan hydrogels improve mesenchymal stem cell delivery into high-oxidative-stress wounds

Cell-based therapies for wound repair are limited by inefficient delivery systems that fail to protect cells from the acute inflammatory environment. Here, a biomimetic hydrogel system is described that is based on the polymer pullulan, a carbohydrate glucan known to exhibit potent antioxidant capabilities. It is shown that pullulan hydrogels are an effective cell delivery system and improve mesenchymal stem cell survival and engraftment in high-oxidative-stress environments. The results suggest that glucan hydrogel systems may prove beneficial for progenitor-cell-based approaches to skin regeneration.     

Practical approach for macroporous structure embedded microfluidic system and the catalytic microchemical application

We present a low cost and practical approach to integrate 3D ordered macroporous polyfluoropolyether (PFPE) patterns into a microchannel by a series of porous pattern fabrication processes and subsequent photolithography in a site- and shape-selective manner. The 3D ordered macroporous patterns with high-resolution edges were firstly fabricated by microtransfer molding (μ-TM) of the sacrificial polystyrene (PS) template infiltrated with PFPE as a non-adhesive and solvent-resistant skeletal material. The resulting robust PFPE porous structures with high solvent resistance on a silicon wafer can easily be embedded into the microchannel with the aid of conventional photolithography, leading to a microfluidic system with a built-in microstructure. Moreover, catalytic Pd nanoparticles implanted on the surface of the porous structure were obtained by use of Pd nanoparticle deposited PS spheres, the porous structure embedded channel was utilized to perform a Suzuki coupling reaction.     

Curcumin-loaded biocompatible thermoresponsive polymeric nanoparticles for cancer drug delivery

This study aims at the formulation of curcumin with biodegradable thermoresponsive chitosan-g-poly (N-vinylcaprolactam) nanoparticles (TRC-NPs) for cancer drug delivery. The spherical curcumin-loaded nanoparticles of size 220 nm were characterized, and the biological properties were studied using flow cytometry and cytotoxicity by MTT assay. The in vitro drug release was higher at above LCST compared to that at below LCST. TRC-NPs in the concentration range of 100-1000 μg/mL were non-toxic to an array of cell lines. The cellular localization of the curcumin-loaded TRC-NPs was confirmed from green fluorescence inside the cells. The time-dependent curcumin uptake by the cells was quantified by UV spectrophotometer. Curcumin-loaded TRC-NPs showed specific toxicity to cancer cells at above their LCST. Flow cytometric analysis showed increased apoptosis on PC3 compared to L929 by curcumin-loaded TRC-NPs. These results indicate that novel curcumin-loaded TRC-NPs could be a promising candidate for cancer drug delivery.     

Presence of pseudo‐peptide bond in the crystal structure of n‐(t‐butoxycarbonyl)‐ε‐n′‐benzyloxycarbony‐l‐lysyl‐l‐isoleucine (boc‐lys(obzl)‐ile)

The dipeptide Boc‐Lys(OBzl)‐Ile crystallizes in monoclinic space group P2₁ with cell parameters a = 5.003(1), b = 19.199(3), c = 15.270(2)Å, β =93.42(1)°, V = 1464.1(3)ų, Z = 2, D_cal = 1.117 Mg/m³ at T = 293 K. The structure was solved by direct methods and refined by full‐matrix least‐squares procedure to a final R = 0.096 and wR = 0.101 using 1379 reflections. The peptide unit is in trans conformation and the molecule takes up an extended conformation. In the lysine side chain, delocalization of electrons and pseudo peptide bond formation is observed at the interaction site of benzyloxycarbonyl group. Both N‐H…O and main chain C‐H…O hydrogen bonds stabilize the molecules in the unit cell in a parallel β‐sheet fashion. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Studies of isomer stability using the maximum hardness principle (MHP)

In the present study, a number of positional and geometrical isomers have been considered to study the stability of isomers using the maximum hardness principle (MHP). All the considered isomeric molecules were optimized and the chemical hardness η and chemical potential μ were calculated at the HF/6‐31G level of theory. The MHP was not able to predict the stability of the most of the positional isomeric molecules, because of the variation in the chemical potential μ and external potential v(r), which arises due to the formation of a bond with different atoms. But, for the most of geometrical isomers, the MHP was able to predict the most stable conformer of the molecule. So, the present investigation suggests that the MHP is not applicable for the prediction of isomer stability for all the isomeric molecules. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 76: 648–655, 2000     

High-rate electrochemical performance and structure elucidation of hydrothermally synthesized nickel zincate nanorods

Journal of Solid State Electrochemistry - For the first time, nanorods of nickel zincate (NiZnO2) have been synthesized by the hydrothermal method and used in supercapacitor electrode fabrication....     

Electron–phonon coupling and vibrational modes contributing to linear electro‐optic effect of the efficient NLO chromophore 4‐(N,N‐dimethylamino)‐N‐methyl‐4′‐toluene sulfonate (DAST) from their vibrational spectra

The optimized geometry and structural features of the most prospective electro‐optic crystal 4‐(N,N‐dimethylamino)‐N‐methyl‐4′‐toluene sulfonate (DAST), and the vibrational spectral investigations have been comprehensively described with the near infrared Fourier transform (NIR FT) Raman and Fourier transform infrared (FT‐IR) spectra supported by the density functional theoretical (DFT) computations to elucidate the contribution of vibrational modes to the linear electro‐optic (LEO) effect. Mulliken population analysis and natural bond orbital (NBO) analysis have also been carried out to analyze the effects of intramolecular charge transfer (ICT), intramolecular hydrogen bonding and hyperconjugative interactions on the geometries. The influence of CT interaction between the phenyl ring and the dimethylamino group of the nonlinear optical (NLO) chromophore on the endocyclic and exocyclic angles, and the electronic effects such as hyperconjugation and back‐donation on the methyl hydrogen atoms have been examined. The concurrent intense activation of Raman and IR activities of the effective conjugation vibrational coordinate, which significantly contributes to the LEO effect resulting from the strong electron–phonon (e/ph) coupling, has been analyzed in detail. The effects of frontier orbitals, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), transition of electron density (ED) transfer and the influence of planarity in the stilbazolium ring on the first hyperpolarizability are also discussed. Copyright © 2008 John Wiley & Sons, Ltd.