Current Nanoscience - Volume 15, Issue 4, 2019

Vertically Aligned Carbon Nanotubes array which is also sometimes labeled as carbon nanotubes forests has many applications in several engineering fields for its remarkable mechanical, electrical, optical, and thermal properties. The Vertically Aligned Carbon Nanotubes array is often employed in developing microdevices such as pressure sensor, angle sensor, switches, etc. To successfully integrate carbon nanotubes forest to the micro-electro-mechanical systems based devices, micropatterning of the carbon nanotubes forest is required. There are several methods available to realize micropatterning of Vertically Aligned Carbon Nanotubes array, from in-situ patterning during the growth process to post-patterning process. Each has its advantages and disadvantages. This paper will discuss elaborately different patterning processes of the carbon nanotubes forest and their different characteristics.

Background: Significant efforts in direction of development of smart windows with natural colour switching properties, which are in the current interest. The tailoring of the electrical conductivity as n-type and p-type is still a major challenge. In this regard, NiO has emerged as a potential candidate and auspicious functional material for various applications. Objective: The main objective is to compile the interesting findings of the authors in context to the effect of the different filler on the properties especially electric and magnetic of NiO on one platform. Methods: Literature survey has been done in the depth. As a whole near about 192 Research articles which include oldest as well as recent coverage about the NiO. Conclusions: Review report conclude that instead of Mott insulator NiO is a kind of charge transfer insulator and accepted extensively theoretically as well as experimentally.

Hydrogels are three-dimensional polymer networks capable of absorbing and holding a large amount of water. They have a wide range of biomedical applications including drug carriers, biosensors, tissue scaffolds and wound dressings owning to their innate resemblance to the living tissue. Recently biodegradable and renewable natural polymers, especially nanocellulose, have gained immense attention in the development of hydrogels for biomedical applications. This review provides a brief analysis of the various nanocellulosic materials used in the fabrication of hydrogels for various biomedical applications. Recent developments in high performance hydrogels based on nanocellulose, including self-healing, highly tough and/or stretchable and 3D printable hydrogels will also be covered in this review.

Targeted drug delivery (TDD) is an advanced and smart method of delivering drugs to the patients in a targeted sequence that increases the concentration of delivered drug only at the targeted body part of interest (organs/tissues/cells). This will in turn enhance efficacy of treatment by reducing side effects and the required dose of the drug. TDD ensures a certain defined minimally required constant amount of a therapeutic agent for a prolonged period of time to a targeted diseased area within the body. This helps maintain the required plasma and tissue drug levels in the body thereby avoiding any damage to the healthy tissue via the drug. Various drug carriers that are envisaged in advanced delivery systems are soluble polymers, inorganic nanoparticles, magnetic nanoparticles, biodegradable microsphere polymers (synthetic and natural), neutrophils, fibroblasts, artificial cells, lipoproteins, liposomes, micelles and immune micelle. In selecting such a vehicle, important factors to consider are chemical and physical properties drugs, side effects or cytotoxicity to healthy cells, route to be taken for the delivery of the drug, the targeted site, and the disease. As such, TDD formulations are prepared by considering the specific properties of target cells, nature of markers or transport carriers or vehicles, which convey drug to specific receptors, and ligands and physically modulated components.

Background: The photocatalytic activity of SnO2-TiO2 nanocomposites was successfully assessed after synthesis by Sol-Gel method, deposition on porous silicon material and annealing at 400, 600 and 800oC temperatures, with surface grain size in the range between 5 and 12 nm. The photocatalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscopy (SEM), thermogravimetric analysis (TGA), derivative thermogravimetry (DTG) and mass spectroscopy (MS). The photocatalytic assessment suggests that this SnO2-TiO2 photocatalyst presents important photocatalytic efficiency to methyl blue (MB) at low annealing temperature. Methods: In this work, sol-gel method is used to prepare SnO2-TiO2 nanocomposites; which were deposited on porous silicon, annealed at different temperatures and investigated to understand their structural, morphological, optical and physical properties. Their photocatalytic activity was evaluated by using the degradation of MB under irradiation with UV light. Results: The intensity of the characteristic absorption band of methyl blue at 655 nm decreased significantly with the increasing irradiation time. Meanwhile, a change in color of the solution occurred; turning from blue to colorless after 20 min of irradiation, and thus indicating the gradual decomposition of methyl blue molecules during UV light irradiation in the presence of the prepared SnO2-TiO2. As expected, no degradation of the SnO2-TiO2 nanocomposites occurred under control experimental conditions. The MB degradation efficiency was reported by C/C0 quantity; where C and C0 correspond respectively to its concentration at time t and initial concentration. In the presence of photocatalysts, it can be clearly deduced that after irradiation for 20 min, the C/C0 of the MB value was about 0% with the prepared and untreated nanocomposites of SnO2-TiO2 and remains constant when using a SnO2-TiO2 nanocomposite treated at 800°C. Conclusion: This research has successfully synthesized the SnO2-TiO2 nanocomposite photocatalysts by Sol-Gel process and deposited by spin–coating technique on porous silicon substrates. Besides, all structural, optical and catalytic properties were studied and CO related. The obtained material was annealed at three different temperatures 400°C, 600°C and 800°C. It is denoted that its grain size increases from about 5 nm to 12 nm with the annealing temperature. The photocatalytic effect has been tested on the MB solution, which demonstrates that the nanometric grain size enhances the adsorption properties and achieves a good photocatalytic performance at a low temperature.

Background: An optimized tree-type cylindrical-shaped nanoporous filtering membrane has been proposed. The performance of this membrane needs to be investigated. Objective: The study aimed to investigate the maximum number of the branch pores in each pore tree practically applied in this proposed membrane. Methods: The analysis for the flow and transport of the filtered liquid in this membrane was derived based on the nanoscale flow equation. The flow resistance of this membrane was defined and its lowest value was found for the optimal condition. Results: The dimensionless lowest flow resistance I f ,min of the membrane in the optimal condition was calculated respectively for weak, medium-level and strong liquid-pore wall interactions, when both the radius Rb,1 of the branch pore and the number N of the branch pores in each pore tree were widely varied. It was shown that for any kind of liquid-pore wall interaction and any Rb,1 value, when N is over 10, the value of I f ,min becomes slowly reduced with the increase of N; Even for N=50, the value of I f ,min is only modestly reduced compared to that for N=10 for the same operating condition. Conclusion: It is suggested that the value of the maximum number Nmax of the branch pores in each pore tree in this membrane should be taken as around 10 in spite of liquid-pore wall interactions, from the viewpoint of engineering application.

Background: In recent years, new nanomaterials have received great attention due to their widespread use in agriculture, food safety and pharmacy. Among them, graphene and graphene oxide (GO) are emerging as promising nanomaterials, which may have far-reaching effects on pharmacy and health. Objective: In this paper, the living Hela cells were covered by GO (Hela@GO) and the cell viability, reactive oxygen species, membrane integrity and apoptosis of them were compared with the control Hela cells, especially under the stress from four kinds of organic solvent, including dimethyl sulphoxide, ethanol, acetone, and glycerin. Results: It was suggested that the GO may protect cells by covering the cells, keeping their membrane integrity, reducing the ROS and decreasing the apoptosis. Conclusion: GO has attracted the tremendous attention of their bioapplications. In this research, the GO adhered to Hela cells. It was observed that the Hela@GO grew well. Besides, it was suggested that the GO would play a protective role to Hela cells against four organic solvents, by maintaining the cell membrane integrity, reducing ROS, and inhibiting the apoptosis.

Background: CuFe2O4 nanoparticles possess good electrochemical properties apart from their inadequate electronic conductivity and large volume variation. The resulting performance lag can be modified by the addition of conductive materials to form a composite. Hence, the properties of CuFe2O4/rGO nanohybrid are presented for application as anode material for lithium-ion batteries. Methods: The composites are synthesized through a facile one-step method of thermochemical reaction. The samples are characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Fourier transform infrared spectroscopy (FTIR), Dielectric behavior and Galvanostatic charge-discharge test. Result & Conclusion: The XRD analysis confirmed the reduction of GO and formation of CuFe2O4/rGO composite, whereas FTIR results showed two major vibrational bands that correspond to spinel structure formation and attachment of rGO to CuFe2O4. The SEM images confirmed tethering of CuFe2O4 nanoparticles with rGO sheets. It was also observed that the formation of the nanohybrid of CuFe2O4 with rGO resulted in expected enhancement of the dielectric properties; dielectric constant and AC conductivity. At 100 Hz frequency, the dielectric constant of the composite with 15 wt. % of GO was 1.2705, which is higher than that of pure CuFe2O4 (3.5704). The parameters such as charge storage capacity and rate capability, which are reminiscent of battery performance were also enhanced with the increase of rGO content in the composite. Hence, a substantial enhancement of battery performance was depicted that projects the composite as a promising candidate for applications in electrode material for lithium-ion batteries.