Nanodendrite—promising nanoreinforcement for emerging next-generation nanocomposite

Graphene oxide (GO) nanostructures have been aligned between conducting electrodes via dielectrophoresis (DEP) with different electrical configurations. The arrangement of ground with respect to peak-to-peak voltage (Vpp) plays a crucial role in manipulating the GO nanostructures. Grounds on both sides of the Vpp electrode give an excellent linking of GO nanostructures which is explained by scanning electron microscopy and current-voltage characteristics. A finite element method simulation explains the electric field and voltage variation profile during DEP process. The optimized aligned GO nanostructures are used as hydrogen gas sensor with a sensitivity of 6.0% for 800 ppm hydrogen gas.

Dielectrophoresis of graphene oxide nanostructures for hydrogen gas sensor at room temperature

Three-dimensional (3D) graphene networks are performance boosters for functional nanostructures in energy-related fields. Although tremendous intriguing nanostructures-decorated 3D graphene network...

Alternating current dielectrophoresis (DEP) is an excellent technique to assemble nanoscale materials. For efficient DEP, the optimization of the key parameters like peak-to-peak voltage, applied frequency, and processing time is required for good device. In this work, we have assembled graphene oxide (GO) nanostructures mixed with platinum (Pt) nanoparticles between the micro gap electrodes for a proficient hydrogen gas sensors. The Pt-decorated GO nanostructures were well located between a pair of prepatterned Ti/Au electrodes by controlling the DEP technique with the optimized parameters and subsequently thermally reduced before sensing. The device fabricated using the DEP technique with the optimized parameters showed relatively high sensitivity (∼10%) to 200 ppm hydrogen gas at room temperature. The results indicates that the device could be used in several industry applications, such as gas storage and leak detection.

The core factors affecting the efficiency of photocatalysis are predominantly centered on controllable modulation of anisotropic spatial charge separation/transfer and regulating vectorial charge transport pathways in photoredox catalysis, yet it still meets with limited success. Herein, we first conceptually demonstrate the rational design of unidirectional cascade charge transfer channels over transition metal chalcogenide nanosheets (TMC NSs: ZnIn2S4, CdS, CdIn2S4, and In2S3), which is synergistically enabled by a solid-state non-conjugated polymer, i.e., poly(diallyldimethyl ammonium chloride) (PDDA), and MXene quantum dots (MQDs). In such elaborately designed photosystems, an ultrathin PDDA layer functions as an intermediate charge transport mediator to relay the directional electron transfer from TMC NSs to MQDs that serve as the ultimate electron traps, resulting in a considerably boosted charge separation/migration efficiency. The suitable energy level alignment between TMC NSs and MQDs, concurrent electron-withdrawing capabilities of the ultrathin PDDA interim layer and MQDs, and the charge transport cascade endow the self-assembled TMC/PDDA/MQD heterostructured photosystems with conspicuously improved photoactivities toward anaerobic selective reduction of nitroaromatics to amino derivatives and photocatalytic hydrogen evolution under visible light irradiation. Furthermore, we ascertain that this concept of constructing a charge transfer cascade in such TMC-insulating polymer-MQD photosystems is universal. Our work would afford novel insights into smart design of spatial vectorial charge transport pathways by precise interface modulation via non-conjugated polymers for solar energy conversion.

New hole-transporting pendant polymers with high glass- transition temperatures (Tgs) above 200 oC were designed and synthesized. Multilayer organic electrolu minescent (EL) devices using the new polymers as the hole-transport layer and quinacridone-doped tris(8-quinolinolato)aluminum as the emitting layer exhibited high performance. One of the hole-transporting polymers functioned well as a hole injection buffer layer in organic EL devices. New green- and orange-emitting penda nt polymers with high Tgs and desired ambipolar character were also designed and synthesized. Organic EL devices using these emitting polymers also exhibited good performance. One of the hole-transporting polymer showed a high hole carrier mobility of over 10 i 3 cm 2 V i 1 s i 1 at an electric field of 1.0 × 10 5 Vcm i 1 , as determined by a time-of-flight method. Keywords : non-conjugated pendant polymers, hole-transpor ting polymers, emitting polymers, hole-injection buffer layer, hole-transport layer, hole drift mobility 1. INTRODUCTION S -Conjugated polymers have received a great deal of attention as materials for electronics and optoelectronics, and have been the subject of recent extensive studies. On the other hand, non-conjugated polymers containing pendant S -electron systems generally have the following characteristic features; a variety of S -electron systems with various functions for pendant groups, chemical stability, solubility in organic solvents, processability such as film-forming capability, and the invariance of oxidation and reduction potentials irrespective of the doping degree. We have performed a series of studies on non-conjugated polymers containing pendant S -electron systems in the light of the consideration that such polymers also constitute a new class of photo- and electroactive materials for electronic, optoelectronic, and photonic devices, permitting the formation of large-area homogeneous films with mechanical strength by wet processes. We have developed several classes of photo-and electroactive pendant polymers. They include electrically conducting polymers, which have found applications as electrode materials for secondary

The activation of T helper (Th) lymphocytes is necessary for the adaptive immune response as they contribute to the stimulation of B cells (for the secretion of antibodies) and macrophages (for phagocytosis and destruction of pathogens) and are necessary for cytotoxic T-cell activation to kill infected target cells. For these issues, Th lymphocytes must be converted into Th effector cells after their stimulation through their surface receptors TCR/CD3 (by binding to peptide-major histocompatibility complex localized on antigen-presenting cells) and the CD4 co-receptor. After stimulation, Th cells proliferate and differentiate into subpopulations, like Th1, Th2 or Th17, with different functions during the adaptative immune response. Due to the central role of the activation of Th lymphocytes for an accurate adaptative immune response and considering recent preclinical advances in the use of nanomaterials to enhance T-cell therapy, we evaluated in vitro the effects of graphene oxide (GO) and two types of reduced GO (rGO15 and rGO30) nanostructures on the Th2 lymphocyte cell line SR.D10. This cell line offers the possibility of studying their activation threshold by employing soluble antibodies against TCR/CD3 and against CD4, as well as the simultaneous activation of these two receptors. In the present study, the effects of GO, rGO15 and rGO30 on the activation/proliferation rate of these Th2 lymphocytes have been analyzed by studying cell viability, cell cycle phases, intracellular content of reactive oxygen species (ROS) and cytokine secretion. High lymphocyte viability values were obtained after treatment with these nanostructures, as well as increased proliferation in the presence of rGOs. Moreover, rGO15 treatment decreased the intracellular ROS content of Th2 cells in all stimulated conditions. The analysis of these parameters showed that the presence of these GO and rGO nanostructures did not alter the response of Th2 lymphocytes.

Surface modified graphene oxide nanosheets by gold ion implantation as a substrate for surface enhanced Raman scattering

Nanoparticles have been crucial in redesigning tumour eradication techniques, and recent advances in cancer research have accelerated the creation and integration of multifunctional nanostructures. In the fight against treatment resistance, which has reduced the effectiveness of traditional radiation and chemotherapy, this paradigm change is of utmost importance. Graphene oxide (GO) is one of several nanoparticles made of carbon that has made a splash in the medical field. It offers potential new ways to treat cancer thanks to its nanostructures, which can precisely transfer genetic elements and therapeutic chemicals to tumour areas. Encapsulating genes, protecting them from degradation, and promoting effective genetic uptake by cancer cells are two of GO nanostructures' greatest strengths, in addition to improving drug pharmacokinetics and bioavailability by concentrating therapeutic compounds at particular tumour regions. In addition, photodynamic treatment (PDT) and photothermal therapy (PTT), which use GO nanoparticles to reduce carcinogenesis, have greatly slowed tumour growth due to GO's phototherapy capabilities. In addition to their potential medical uses, GO nanoparticles are attractive vaccine candidates due to their ability to stimulate cellular and innate immunity. These nanoparticles can be used to detect, diagnose, and eradicate cancer because they respond to certain stimuli. The numerous advantages of GO nanoparticles for tumour eradication are attributed in large part to their primary route of internalisation through endocytosis, which guarantees accurate delivery to target locations. The revolutionary potential of multifunctional nanostructures in cancer treatment is highlighted in this extensive compendium that examines current oncological breakthroughs.

Multiple nanostructures of graphene oxide (GO) and Zinc oxide (ZnO) have been prepared via alcoholic reduction of GO, where took place the ZnO incorporation with different weight ratios. The X-ray diffraction patterns shown the ZnO anchored between GO sheets consequently produce a significant displacement of the GO characteristic pattern to lowers angles. In addition, the alcoholic reduction process allows generating another Zinc Nanostructure, the presence of Zinc Peroxide (ZnO2) is confirmed by two signals at 37.8° and 43.1° in XRD. The metallic semiconductor anchored is evident in Raman Spectra, because a displacement of D and G band. The ZnO characteristics bands appear in the spectra, however, near to 474 cm−1 a small band is shown, this band indicates the presence of ZnO2, reaffirming the observed in XRD. In thermogravimetric analysis (TGA) the materials (GO, rGO/ZnO) shown similar tendencies, but, in DTG curves is observed different reactions because the species presents in the materials. Bandgap estimation was calculate by Reflectance UV–vis spectroscopy, adjusted by Kubelka-Munk, all rGOZnO material presents visible light activation. By photodegradation of Methylene Blue (MB) under sunlight confirms the Bandgap estimation obtained by Kubelka-Munk. In this work, the alcoholic reduction of GO for metallic semiconductors anchored is a viable method, improving optical and electronic properties of ZnO, allowing these material multiple applications such as optoelectronic, photovoltaic devices and photocatalysis.

Graphene oxide (GO) and its derivatives are considered as a promising drug carrier in tumor therapy due to their excellent biocompatibility. Here, a series of nanostructured GO with long‐range ordered lamellar or hexagonal structure were prepared by lyotropic liquid crystals (LLCs) templating strategy and used as drug carriers. The nanostructure was verified via polarized‐light optical microscopy (POM), low angle X‐ray diffraction (XRD) and transmission electron microscopy (TEM), which showed that the interlayer spacing or pore size was determined by the carbon chain length of templating molecular. 5‐fluorouracil (5‐Fu), doxorubicin (DOX) and docetaxel (DOC) which had gradually increased molecular size were chosen as model drugs, and the highly ordered nanochannels can be used as space for adsorption and diffusion of drug molecules. Ultraviolet spectrometer and simulated release test in vitro were used to determine drug loading capacity and drug release performance. The results showed that larger pore diameter/layer spacing was beneficial to the adsorption and diffusion of drug molecules, especially those with shorter molecule size. Besides, the water‐solvable DOX exhibited fast release rate than the hydrophobic 5‐Fu and DOC. The in vitro cytotoxicity assay demonstrated the good biocompatibility of both the pristine GO and the nanostructured GO.

Background: Nanotechnology is used in stem cell culture as well as in vivo delivery and tracking of stem cells. Graphene oxide (GO) is a carbon based nanomaterial and it has large surface area as well as good biocompatibility and heteroatoms doped GO exploit its properties. Hybrid GO (hGO) nano structures biocompatibility is depends on its size, dose and exposure time as well as in vitro cell models and hence, need thorough cytotoxicity studies in different species in vitro cell models. Methods: Caprine Wharton’s jelly derived mesenchymal stem cells (WJ-MSCs) were isolated, characterized and dose dependent (100, 50, 25, 10 and 0µg /ml) in vitro cytotoxicity of three different hGO nano structures (phosphorus doped graphene oxide titanium oxide tubes, rods and sheets) were analysed in caprine WJ-MSCs by studying cell cytotoxicity assays. Result: All three hGO nano structures were damaged cell morphology at 100 and 50 µg /ml doses, however, morphologically more good cells were observed in hGO tubes treated group than hGO rods and hGO sheets at 25 and 10 µg/ml doses as compared to control. Cell viability percentage was significantly (P less than 0.01) decreased at dose 100 µg/ml and it was significantly (P less than 0.01) increased at 25 µg/ml dose as compared to 50, 10 and 0 µg/ml doses. But, hGO tubes significantly (P less than 0.01) increased cell viability % as compared to hGO rods and hGO sheets. Cell population doubling time (PDT) was not altered significantly by all hGO nano structures, but 100 and 50 µg/ml doses significantly (P less than 0.01)increased cell PDT as compared to 25, 10 and 0 µg/ml doses. All hGO nano structures were non significantly altered growth curve, however, all hGO nano structures at 25 µg /ml dose altered (inclined) shape of growth curve, while 100 and 50 µg /ml doses significantly declined growth curve shape as compared to 10 and 0 µg /ml doses. Cell proliferation % was significantly (P less than 0.01) increased at 25 and 10 µg/ml doses, while, it was significantly (P less than 0.01) decreased at 100 µg /ml dose as compared to 50 and 0 µg /ml. However, there was no significance difference was observed in cell proliferation % in groups treated by different hGO nanostructures. In last, it was concluded as, hGO nano structures cytotoxicity was dose dependent and hGO nano tubes were least cytotoxic in caprine WJ-MSCs.

In this work we prepared graphene oxide nanostructures (GONE) in a liquid environment using pulsed laser ablation technique. We used for the synthesis Nd: YAG pulsed laser operatating at 1064 nm and 532 nm of wavelength, we study the effect of wavelength of the laser on the optical properties of Nanostructures (NE) synthesized. The aim was determining the optical bandgap and the characteristic peak related by bond transitions using the absorbance UV-Vis spectra. Both samples show high absorption in the ultraviolet region in the UV-Vis spectra. Using Tauc’s plot method we compute the bandgap energy for GONEs assuming indirect bandgap. In addition, we observe characteristic peak formation 1 hour after synthesized NPs at 256 nm for NPs prepared at 1064 nm and for NPs prepared at 532 nm the peak with less intensity is observed at a wavelength of 218 nm. The characteristic peak for both samples increase of intensity 24 hours after preparation.

Surface charge transfer doping (SCTD) has been established as an efficient strategy to achieve strong electronic coupling interactions between semiconductors and dopants, which lead to highly efficient electron transport over semiconductors. Herein, we report a facile, easily accessible, and effective SCTD strategy to exquisitely modulate the interfacial charge transfer over transition metal chalcogenides (TMCs: CdS, Zn0.5Cd0.5S, CdIn2S4, and ZnIn2S4) through surface modification with a nonconjugated polymer, poly(dimethyldiallylammonium chloride) (PDDA). We provide evidence that PDDA, as a surface electron transfer acceptor, can be used to enable rapid, directional, and tunable charge transfer along with an optimal charge lifetime over TMCs in photoredox catalysis because of the high-efficiency electron-trapping property of quaternary ammonium functional groups in the molecular structure of PDDA. The thus-assembled PDDA-encapsulated TMC composite artificial photosystems demonstrate significantly enhanced and versatile photoredox catalytic activities toward visible-light-responsive photocatalytic reduction of aromatic nitro compounds, photocatalytic oxidation of aromatic alcohols, and photocatalytic H2 production, wherein the ultrathin PDDA layer accelerates the interfacial charge transport and separation rate over TMC substrates. Moreover, it was evidenced that such an interface engineering strategy is general for a collection of TMCs. Our work will provide conceptual insights into nonconjugated polymer-based artificial photosystems for optimizing solar energy utilization.

Interfacial properties of Co3O4/Gd–Fe2O3 p-n junction photoanode improved by PDDA functional layer for efficient photoelectrochemical water oxidation