Current Nanoscience - Volume 14, Issue 1, 2018

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disorder involving defects in epidermal barrier function and abnormal immune response to environmental stimuli. Standard treatment of AD involves topical application of emollients and anti-inflammatory drugs such as corticosteroids. Objective: Because of the barrier function defects in AD skin, the topical drug delivery can lead to systemic drug absorption, thereby eliciting systemic complications. Nanoparticles as the carriers used for cutaneous drug delivery provide some benefits over conventional formulations, including enhanced stability, improved epithelium permeability and bioavailability, controlled drug release, skin targeting, and minimal side effects. In recent years, the concept of using nanocarriers as vehicles for drug delivery to manage AD has attracted increasing attention. Polymeric nanoparticles, lipid nanoparticles, and liposomes are the most extensively studied nanocarriers for the treatment of AD. In this review, we highlight the recent progress on the development of nanosystems for AD treatment. Method: We systematically introduce the concepts and amelioration mechanisms of the nanomedical techniques for AD treatment. Different AD animal models for evaluating the efficacy of the therapeutic nanoparticles are described herein. Results: The discrepancy of the nanoparticle skin absorption between healthy skin and AD skin is also discussed. Conclusion: This review aimed to summarize the evidence for the therapeutic advantages of nanoparticles over the conventional AD therapy.

Background: Pyrochloro structured Sm2Ti2O7 has photocatalytic activity on degradation of organic substances and on hydrogen evolution from water. Powder materials usually encounter the obstacle of separating from treated water. HZSM-5 zeolite is a kind of porous structured material with large surface area. Its role as a support for Sm2Ti2O7 is interesting. Methods: The supported Sm2Ti2O7 was synthesized using sol-gel method. The composite χSm2Ti2O7/HZSM-5 was characterized by XRD, SEM, TEM, FT-IR/FIR, UV-Vis DRS, N2 adsorption- desorption and XPS measurements. Photocatalytic degradation of Reactive Brilliant Red X-3B (RBR X-3B) was measured to evaluate the activity of the composite. Results: Sm2Ti2O7 is in the pyrochlore phase after loading on the surface of HZSM-5 zeolite. The crystal cell of pyrochlore Sm2Ti2O7 continuously expanses with decreasing Sm2Ti2O7 loading content in the composite. Bandgap energy of Sm2Ti2O7 is enlarged after supporting. The specific surface area of Sm2Ti2O7 was enlarged from 9.8 m2/g to 93 m2/g after loading. Both of the adsorption capacity and photocatalytic activity of the χSm2Ti2O7/HZSM-5 are greater than those of pure Sm2Ti2O7. After 120 min of irradiation, 73.1% of the initial RBR X-3B molecules are decomposed on 70%Sm2Ti2O7/HZSM-5, and only 27.7% of the dye is decomposed on the bare Sm2Ti2O7. Conclusion: Sm2Ti2O7 crystal growth is constrained after loading due to dispersion of Sm2Ti2O7 on the surface of HZSM-5. The specific surface area of Sm2Ti2O7 is significantly enlarged after loading. All the supported samples have greatly enhanced photocatalytic activity as compared to the bare Sm2Ti2O7.

Background: Binary metal oxides, such as spinel nickel cobaltite (NiCo2O4), are attractive pseudocapacitive materials in electrochemical supercapacitors because they have higher theoretical capacitance than carbonaceous materials, and higher electronic conductivity than conventional monometal oxides. However, their practical pseudocapacitive performance is dramatically hindered by traditional electrode assembly technologies, through which extremely high internal resistances are generated at supplementary interfaces within nanostructured binary metal oxides and between binary metal oxides/current collector. Methods: Here, we develop polymer-binder-free hybrid electrodes by employing Ni nanotube arrays as 3D current collectors for the loading of electroactive NiCo2O4 nanosheets (Ni/NiCo2O4 nanotube array). Results: As a result of the remarkably enhanced electronic conductivity and ion diffusion, the Ni/NiCo2O4 nanotube array electrodes exhibit a specific capacitance of as high as ~753 F g-1 at a scan rate of 5 mV s-1 and rate performance, in addition to a long-term cycling stability. Conclusion: The outstanding performance makes the Ni/NiCo2O4 nanotube array to be an efficacious power source electrode in a wide range of applications.

Background: Chemotherapy, the predominant cancer treatment modality, suffers from elimination in renal and hepatic systems causing reduced bioavailability and increased toxicity leading to harmful side effects. Targeted release of formulations encapsulated in protective biocompatible polymer or polymer-lipid microbubbles can improve bioavailability and potency while reducing systemic toxicity, resulting in a higher therapeutic index. Objective: Double emulsion, the most common method for microbubble fabrication suffers from low encapsulation efficiency and wide size distributions. In this concise article, we analyze the emergent coaxial electrospray technique vis-is established double emulsion methods to manufacture biocompatible polymer microbubbles for targeted drug delivery systems. Method: Specifically, we investigate size, morphology, and encapsulation efficiencies of microbubbles fabricated using double emulsion and coaxial electrospray techniques. Results: We found that microbubbles produced via coaxial electrospray displayed higher encapsulation efficiency and a narrower size distribution. Conclusion: Coaxial electrospray is a promising technology with considerably improved size distribution and encapsulation efficiency; however, reproducibility across facilities and scale remain challenging.

Background: Superparamagnetic iron oxide nanoparticles (SPIONs) are known for various biomedical applications like hyperthermia, magnetic resonance imaging and drug delivery. These magnetic particles should be capped with certain biocompatible agents. In this regard, it is a technological challenge to control size, shape, stability, and dispersibility of SPIONs in desired mediums. Methods: Cathodic electrosynthesis procedure was used for the preparation of naked SPIONs. Naked SPIONs were prepared by galvanostatic electrodeposition by applying the current density of 5 mA cm-2 for 30 min. For preparation of chitosan capped SPIONs, only the composition of deposition electrolyte was changed with the addition of 1 g L–1 chitosan. The prepared NPs were characterized through FE-SEM, TEM, XRD, DLS and VSM techniques. Results: The XRD patterns have the well-defined and relative broad diffraction peaks, which confirmed spinal magnetite structure for both naked CS capped SPIONs. FE-SEM images which clearly showed that both samples have a well-defined 10nm particles with no obvious aggregation. IR bands related to the chemical bonds of chitosan were observed, which proved a chitosan coating. The superparamagnetic nature of the prepared naked and CS-SPIONs were confirmed by VSM data. Conclusion: In summary, a facile electrochemical based platform was developed for the synthesis of chitosan capped superparamagnetic iron oxide nanoparticles from ethanol media. The observed weight loss (~16%) during the calcination of the CS- SPIONs, and also the presence of vibration bands related to the chitosan bands confirmed the chitosan layer on the SPIONs. Also, superparamagnetic nature of the CS capped SPIONs was confirmed by VSM data.

Background: Metal nanoparticles have been widely investigated due to their unique optical, mechanical, and chemical properties compared with those of the same bulk material. These properties can be tuned by controlling their size or shape, in this sense, several nanomaterials have been obtained by means of both chemical and physical methods. For instance, silver nanoparticles have been obtained in liquid media by using laser ablation or chemical reduction techniques. Another way to obtain a colloidal silver nanoparticles is through the well-known pulsed laser irradiation method which can produce a stable colloidal solution in a few minutes of irradiation and without stabilizing molecules or ligands. Methods: Silver nanopowder suspended in ethanol was irradiated with a pulsed laser at 532 nm via optical fiber. Previously, the fiber was prepared by cleaving and removing its coating and then placed in the middle of a cell. The pulse width was 15 ns and the pulse repetition frequency was 10 kHz. Scanning and transmission electron microscopes were used to observe the silver nanoparticles before and after laser irradiation, respectively. The samples were analyzed by means of UV-Vis spectrophotometer to observe the absorption spectra. Results: The absorption spectra show that particle size distribution increases according to the irradiation time. The colloidal solution showed a color change (from gray to yellow) after having irradiated it for 5 minutes. From TEM images, it can be observed that silver nanopowder was transformed to semispherical particles with diameters smaller than 1μm, however, due to the wide particle size distribution the colloidal solution was centrifuged for 30 min to separate the nanoparticles. Conclusion: The pulsed laser irradiation method via optical fiber was successfully used to obtain a stable yellow colloidal solution. Photomelting, photofusion, and photofragmentation are the responsible phenomena for the change in morphology and size of the silver nanopowder.

Background: Propagation of pathogens has considered an important health care problem due to their resistance against conventional antibiotics. The recent challenge involves the design of functional alternatives such as nanomaterials, used as antibacterial agents. Early stages of antibacterial damage caused by metallic nanoparticles (NPs) were studied by Transmission Electron Microscopy (TEM) and combined Scanning Transmission Electron Microscopy with High Angle Annular Dark Field (STEM-HAADF), aiming to contribute to the elucidation of the primary antibacterial mechanism of metallic NPs. Methods: We analyze the NPs morphology by TEM and their antibacterial activity (AA) with different amounts of Ag and Cu NPs. Cultured P. aeruginosa were interacted with both NPs and processed by TEM imaging to determine NPs adhesion into bacteria wall. Samples were analyzed by combined STEM-HAADF to determine the NPs penetration into bacterium and elemental mapping were done. Results: Both NPs displays AA depending on NPs concentration. TEM images show NPs adhesion on bacterial cells, which produces morphological changes in the structure of the bacteria. STEMHAADF also proves the NPs adhesion and penetration by intracellular localization, detecting Ag/Cu species analyzed by elemental mapping. Moreover, the relative amount of phosphorus (P) and sulfur (S) increases slightly in P. aeruginosa with the presence of NPs. These elements are associated with damaged proteins of the outer cell membrane. Conclusions: Combined microscopy analyses suggest that the early stages of antibacterial damage caused by alteration of bacterial cell wall, and can be considered a powerful tool aiming to understand the primary antibacterial mechanism of NPs.

Background: Achieving a nanofluid with optimal thermal conductivity and viscosity is one of the main problems of applications of nanofluids in industries. Methods: There are experimental and theoretical methods to reach an applicable nanofluids with mentioned characteristics. Surely, experimental methods are not optimal in time and cost($) aspects. So, in the present study multi-objective optimization of nanofluids ND-Co3O4 is done to find the optimal solid volume fraction for having maximum thermal conductivity and minimum viscosity. The response surface methodology (RSM) is used to model target functions using empirical data. The improved non- dominated sorting method and multi-objective particle swarm optimization are used as powerful tools for optimization. In order to implement the optimization process, the obtained target function model is joined to multi-objective particle swarm algorithm and it is used in each step of the target function evaluation. Results: The obtained results of these two algorithms are presented in the form of Pareto front. Also, a comparison between them is provided. According to the optimal results, MOPSO has a better performance that the other one. Conclusion: It will be shown that the highest thermal conductivity and the lowest viscosity occur at the maximum temperature. By investigating obtained optimum results, the optimal point with highest thermal conductivity and lowest viscosity was found at about 60 °C and 0.1 to 0.11 of solid volume fraction.

Background: Seaweeds, being abundant sources of active components have attained much interest in recent times. The seaweeds are routinely used in life science research and are well known for their biological applications. In addition to that, the synthesis of metallic nanoparticles from these natural resources has its own attraction in drug delivery and was observed by using 2 mL of Ag NP colloids. Objective: In this study, the synthesis of silver nanoparticles (Ag NPs) using Padina tetrastromatica has been evaluated for their catalytic activity in the degradation of organic dye. Method: The catalytic activity of the biosynthesized Ag NP colloid was studied for the degradation of Methylene blue (MB) and Acridine orange (AO) dye. The degradation of methylene blue and acridine orange was observed at regular time interval by using UV-vis absorption spectra at 664 nm and 490 nm respectively. Results: The percentage of dye degradation increased in the presence of NaBH4. It was observed that 80.09% of MB dye reduction was observed by using 2 mL of Ag NP colloids. The acridine orange dye showed reduction of 83.06%. The rate constants for the reduction of Methylene blue (MB) and acridine orange (AO) dye using 2 mL Ag NPs colloids are 0.077 and 0.090 min-1, respectively.

Background: Crosstalk will be a major concern in future nano ICs where the components will be scaled down to a few nanometers. In particular, modeling of CNT based interconnects shows that they will suffer from crosstalk when fabricated at smaller technology nodes. Objective: This paper presents reduction of crosstalk and noise in CNT bundle interconnects. We propose the use of small diameter semiconducting CNTs (s-CNTs) as electromagnetic interference (EMI) shields for CNT bundle interconnects. Methods: The coupling capacitance of the proposed CNT bundle structure shows that crosstalk can be reduced significantly by using small diameter s-CNTs. We perform SPICE analysis to show the reduction in crosstalk and peak noise. Results: The proposed bundle geometry reduces 46% crosstalk induced delay and 23% output peak noise as compared to conventional CNT interconnects. Conclusions: Small diameter semiconducting CNTs can be used as EMI shields to reduce crosstalk and noise in CNT interconnects.