Natural bond orbital analysis, salvation, and substituent effects of electron-releasing (–CH3, –OH) and electron-withdrawing (–Cl, –NO2, –CF3) groups at para positions on the molecular structure of synthesized 3-phenylbenzo[ d]thiazole-2(3 H)-imine and its derivatives in selected solvents (acetone, toluene, and ethanol) and in the gas phase by employing the polarizable continuum method model are studied using the M06-2x method and 6-311++G(d,p) basis set. The relative stability of the studied compounds is influenced by the possibility of intramolecular interactions between substituents and the electron donor–acceptor centers of the thiazole ring. Furthermore, atomic charges, electron density, chemical thermodynamics, energetic properties, dipole moments, and nucleus-independent chemical shifts of the studied compounds and their relative stability are considered. The dipole moment values and the highest occupied molecular orbital–lowest unoccupied molecular orbital energy gaps reveal different charge-transfer possibilities within the considered molecules. Finally, natural bond orbital analysis is carried out to picture the charge transfer between the localized bonds and lone pairs.

Peripheral nerve injuries can lead to lifetime loss of function and permanent disfigurement. Different methods, such as conventional allograft procedures and use of biologic tubes present problems when used for damaged peripheral nerve reconstruction. Designed scaffolds comprised of natural and synthetic materials are now widely used in the reconstruction of damaged tissues. Utilization of absorbable and nonabsorbable synthetic and natural polymers with unique characteristics can be an appropriate solution to repair damaged nerve tissues. Polymeric nanofibrous scaffolds with properties similar to neural structures can be more effective in the reconstruction process. Better cell adhesion and migration, more guiding of axons, and structural features, such as porosity, provide a clearer role for nanofibers in the restoration of neural tissues. In this paper, basic concepts of peripheral nerve injury, types of artificial and natural guides, and methods to improve the performance of tubes, such as orientation, nanotechnology applications for nerve reconstruction, fibers and nanofibers, electrospinning methods, and their application in peripheral nerve reconstruction are reviewed.

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Background. Tissue engineering is defined as the designing and engineering of structures to rebuild and repair a body damaged tissue. Scaffolding Poly Hydroxy Butyrate Valerate (PHBV) has shown good biocompatibility and biodegradable properties. Nanofibers have improved the performance of biomaterials, and could be considered effective. One of the important methods for designing nanofiber scaffold is the electrospinnig method. In this study, PHBV nanofibers were well designed and then, modified with the immobilized collagen via the plasma method. The samples were evaluated by ATR-FTIR, SEM, contact angle, and, finally, cell culture.Results. ATR-FTIR structural analysis showed the presence of collagen on the nanofiber surfaces. The SEM images showed the size average of nanofibers as to be about 280 nm; that increased with a collagen coating up to 300 nm. Contact angle analysis showed 67 degree for uncoated nanofibers and 56 degree for coated nanofibers. Cellular investigations (USS cells) showed better adhesion and cell growth and proliferation of coated samples than uncoated samples.Conclusions. In this work, the PHBV nanofibers with a size average about 280 nm were designed. Nanofibers were successfully coated with collagen via the plasma methods. These collagen-coated nanofibers could be used well for tissue engineering.

Surface modification of Fe 3 O 4 nanoparticles with triethoxyethylcyanide groups was used for the immobilization of palladium nanoparticles to produce Fe 3 O 4 /Ethyl-CN/Pd. The catalyst was characterized using Fourier transform infrared, wavelengthdispersive X-ray, energy-dispersive X-ray and X-ray photoelectron spectroscopies, field-emission scanning electron and transmission electron microscopies, and X-ray diffraction, vibrating sample magnetometry and inductively coupled plasma analyses. In this fabrication, cyano groups played an important role as a capping agent. The catalytic behaviour of Fe 3 O 4 /Ethyl-CN/Pd nanoparticles was measured in the Suzuki cross-coupling reaction of various aryl halides (Ar-I, Ar-Br, Ar-Cl) with phenylboronic acid in aqueous phase at room temperature. Interestingly, the novel catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled seven times without any significant loss in activity.

Single-wall carbon nanotubes (SWCNT) represent a novel nanomaterial applied in various nanotechnology fields because of their surface chemistry properties and high drug cargo capacity. In this study, SWCNT are pre-functionalized covalently with paclitaxel (PTX) - an anticancer drug, and folic acid (FA), as a targeting agent for many tumors. The samples are investigated and evaluated by different analyses such as Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), absorption spectroscopic measurements (UV-Visible), elemental analysis, and cell analyses with cancer cell line cultures. The results show good conjugation of the targeting molecule and the anticancer drug on the surface of the carbon nanotubes (CNT). This work demonstrates that the SWCNT-PTX-FA system is a potentially useful system for the targeted delivery of anticancer drugs.

Poly-N-isopropylacrylamide was successfully grafted onto a polystyrene cell culture dish and γ-preirradiated in air. In this study, the effect of a γ-pre-irradiation dose of radiation (radiation absorbed dosages of 10, 20, 30, 40 KGy) under appropriate temperature and grafting conditions was investigated. The Fourier transform infrared spectroscopy analysis showed the existence of the graft poly-N-isopropylacrylamide (PNIPAAm) on the substrate. The optimal value of the dose for grafting was 40 KGy at 50°C. The scanning electron microscopy and atomic force microscopy (AFM) images clearly showed that increasing the absorbed dose of radiation would increase the amount of grafting. Surface topography and graft thickness in AFM images of the radiated samples showed that the PNIPAAm at the absorbed dose of radiation was properly grafted. The thickness of these grafts was about 50–100 nm. The drop water contact angles of the best grafted sample at 37°C and 10°C were 55.3 ± 1.2° and 61.2 ± 0.9° respectively, which showed the hydrophilicity and hydrophobicity of the grafted surfaces. Differential scanning calorimetry analysis also revealed the low critical solution temperature of the grafted sample to be 32°C. Thermoresponsive polymers were grafted to dishes covalently which allowed fibroblast cells to attach and proliferate at 37°C; the cells also detached spontaneously without using enzymes when the temperature dropped below 32°C. This characteristic proves that this type of grafted material has potential as a biomaterial for cell sheet engineering.

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