Current Nanoscience - Volume 18, Issue 1, 2022

Capacitive deionization (CDI), as a novel, energy-efficient, and environment-friendly desalination technology, has received substantial attention in the scientific community during the last five decades, while the electrode materials, acting as the ion storage media, play a vital role during its desalination process. Meanwhile, developing electrode materials from biomass has been proven to be a feasible strategy due to their abundance in nature, unique microstructure, as well as feasibility for further modifications. In this review, various bio-mass-based electrode materials and their unique advantages as CDI electrodes are systematically presented.

Background: The human ken about esoteric phenomenon develops the period from space to the sub-atomic level. The passion to further explore the unexplored domains and dimensions boosts human advancement in a cyclic way. A significant part of such passion follows in the electronics industry. Moore’s law is reaching the practical limitations because of further scaling of metal oxide semiconductor (MOS) devices. There is a need for a more dexterous and effective technological approach. Quantum-dot cellular automata (QCA) is an emerging technology which avoids the physical limitations of the MOS device. QCA is a dynamic computational transistor paradigm that addresses device density, power, operating frequency and interconnection problems. It requires an extensive study to know the fundamentals of logic implementation. Objective: Immense research and experiments led to the evolving nanotechnology and a feasible alternative to complementary metal-oxide semiconductor (CMOS) technology. A comprehensive study is presented in the paper to enhance the basics of QCA technology and the way of implementation of the logic circuits. Different existing circuits using QCA technology are discussed and compared for different parameters. Methods: Scaling the devices can reduce the power consumption of the MOS device. Quantum dots are nanostructures made from semi-conductive conventional materials. It is possible to model these constructions as 3-dimensional (3D) quantum energy wells. Logical operations and data movement are performed using Coulumbic interaction between nearby QCA cells instead of the current flow. Results: The focus of this review paper is to study the trends which have been proposed and compare the designs of various digital circuits. The performance of different circuits such as XOR, adder, reversible gates and flip-flops is provided. Different logic circuits are compared in terms of the parameters such as cell count, area and latency. At least 10 QCA cells are used for the XOR gate with 1 clock latency. Minimum 44 QCA cells are required to make a full adder with 1.25 clock latency. Conclusion: Designers may choose the best-fitted circuit in their logic implementation on the basis of the comparison. The comprehensive study of the QCA technology helps the researchers to learn this field fast and work to make the design of less cell count and latency.

The use of hyperthermal temperature to treat solid cancers is known as oncological thermal ablation. Thermal ablation is studied as a therapeutic strategy for most cancers and can be used in the control of local and metastatic diseases in addition to traditional anticancer therapies. PTT (photothermal therapy) is a minimally invasive therapeutic approach with a promising diagnostic and cancer prevention potential. The excitation of photosensitizer materials like inorganic and organic nanomaterials with NIR (near-infrared radiation) showed significantly better results than the traditional mode of cancer treatment. The penetration depth of NIR is significantly higher as compared to the U.V. (ultraviolet) and visible light. Photo-excitation of the nanomaterials with NIR efficiently converts light energy into heat energy and eventually enables the cancer cells to die due to heat shock. The addition of a multimodal approach to the treatment and the prevention of cancer cells thermo-resistant properties in localized and distal tumors involves the combination of photothermal agents and chemotherapy. Cancer cell hyperthermic activation prevents DNA repair, cell survival signaling and eventually induces apoptosis. Simultaneously, the release of antigenic peptides from the dead cancer cells activates the immune cells which kill the localized and metastatic cancer cells, hence enabling long-term immunological memory retention. The present review summarizes PTT's functional properties, NIR penetration ability, DNA repair, cellular signaling, and immune system modulation effect of hyperthermia. The benefits of using different types of nanomaterials in PTT applications are further explored. In addition, the problems associated with the use of nanomaterials in PTT applications are also addressed in this article.

Background: Dermatological problems impose the biggest challenges for formulation scientists because of the innate structure of the skin that offers an excellent barrier to the topical delivery of drugs. Conventional topical delivery systems are associated with low encapsulation efficiency, stability issue and skin irritation, and reduction in therapeutic efficacy. In recent years, nanocrystal has emerged as an attractive option for topical delivery due to its enhanced saturation solubility, increased surface area, adhesiveness, absence of excipients, and small particle size. Objective: The present review provides a comprehensive account of topical delivery for the management of various dermatological problems through nanocrystal technology. The review highlights the aptness of drug nanocrystals for skin delivery. The various methods used for the fabrication of nanocrystals and the mechanism of skin penetration have been included and dealt with in this review. The main emphasis is on the management of dermatological problems through employing nanocrystals; a plethora of literature and patents based on nanocrystal technology for topical delivery have been included in this review. Conclusion: Nanocrystal-based topical delivery system can be a promising approach for drugs with poor skin penetration as this system possesses the tremendous potential to overcome skin barrier and deliver drugs at relevant concentrations at the local tissue level and avoid skin irritation.

Background: Owing to the excellent theoretical specific capacity and safety intercalation potential, Li3VO4 (LVO) has been proposed as an advanced anode material for lithium ions batteries (LIBs). However, the LVO suffers from low electronic conductivity that limits its commercialization. Objective: The reduced graphene oxide (rGO) is recommended to couple with micro-LVO particles aiming to enhance the conductivity of composite electrodes. Method: The LVO@rGO composite is synthesized by a facile hydrothermal method. The morphology, crystallinity, valance state and electrochemical behavior of LVO@rGO are characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical workstation, respectively. Further, the LIBs’ performance is explored by making a coins-type half-cell LIBs battery via battery system. Results: The Li⁺ diffusion rate of the optimized LVO@rGO electrode is 7.67×10^-23 cm²/s, which improves two orders of magnitudes of pure LVO electrode. As a result, the LVO@rGO anode delivers a reversible capacity of 190.1 mAh/g at 0.1 A/g after 100 cycles, which is even twice higher than that of pure LVO anode (90.6 mAh/g). Besides, it exhibits superior rate capability, i.e. a reversible capability of 285.0, 220.2, 158.7, 105.2 and 71.7 mAh/g at 0.05, 0.1, 0.2, 0.5 and 1.0 A/g, respectively. Conclusion: The high conductivity and flexible texture enable rGO an idea building block to enhance the Li ion diffusion of whole electrode. On the other hand, it is instrumental in alleviating the aggregation of host materials, leading to high specific surface and specific capacity.

Background: Nanocrystalline celluloses (NCCs), also known as nanocelluloses derived from natural renewable resources, have elicited much interest from researchers. The annual local agricultural residues of pineapple leaves and sugarcane bagasse are abundant and must be used properly. The detailed comparative analysis of chemical, physical and thermal properties conducted in this work demonstrates that several types of agro-waste can be utilised economically and reasonably for various applications. Methods: NCCs were successfully isolated by the pre-treatment (alkaline and bleaching) and acid hydrolysis of pineapple leaves and sugarcane bagasse. The structural, crystallinity, morphological and thermal properties were evaluated via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Results: The FTIR spectra revealed an extensive removal of hemicellulose and lignin from the extracted NCC. Morphological investigations conducted through TEM revealed that the NCC nanostructure had a needle-like shape, whereas SEM showed an irregular rod-like shape. The XRD pattern proved the crystallinity of the isolated NCC from both samples. The crystallinity indices of NCC from pineapple leaves and sugarcane bagasse were 76.38% and 74.60%, respectively. NCC’s thermal stability increased in both samples at different purification stages. Conclusion: Pineapple leaves and sugarcane bagasse can be the industry’s primary source of raw materials and a possible alternative for costly and non-renewable materials. The use of NCCs from these agro-waste forms is beneficial and can provide considerable biomass to the agricultural industry with nano-energy-based markets.

Background: The study focuses on the synthesis of chitosan/Fe2O3 nanocomposite, its characterization and application in methyl orange dye degradation. Methods: The synthesized chitosan/Fe2O3 nanocomposite was characterized with Powder X-Ray Diffraction, Fourier Transformation Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and UV-Vis Spectroscopy Results: The characterization showed that the Fe2O3nanoparticles were embedded in the polymer matrix of chitosan. The size of the Fe2O3nanoparticles was less than 10nm and the crystallite size was 1.22 nm. The synthesized chitosan/Fe2O3nanocomposite was tested for methyl orange degradation using different parameters such as the effect of contact time, effect of dose, effect of concentration and effect of pH for the degradation of methyl orange dye in aqueous solution. The Fruendlich, Langmuir and Temkin isotherm studies were also conducted for adsorption of methyl orange on Chitosan/ Fe2O3nanocomposite Conclusion: The study indicated that the synthesized chitosan/Fe2O3 nanocomposite had the potential of degrading methyl orange dye up to 75.04% under the set condition in this experiment, which indicates that Chitosan/Fe2O3 nanocomposite is a viable option that can be used for the degradation of methyl orange dye

Background: The present study outlines the green synthesis of copper oxide (GS-CuO) nanoparticles using Magnolia champaca plant floral extract for the first time. Computational analysis showed the role of GS-CuO nanoparticles on cardiac enzymes ACE2 and SOD1 functional expression through hydrogen bond interaction with amino acid residues Method: The synthesized GS-CuO nanoparticles were characterized by various techniques like XRay Diffraction, UV-Vis Spectrophotometer, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and Transmission Electron Microscopy Results: Nanoparticles demonstrate the presence of spherical shape and size 20 nm. The particles have many active sites as compared to the bulk materials, and thus, computational analysis was conducted against angiotensin-converting enzyme and superoxide dismutase to visualize the cardioprotective effects Conclusion: The in-silico approach established valuable information on the cardioprotective effects of green synthesized oxide nanoparticles using Magnolia champaca.

Background: Semiconductor nanomaterials are being employed for the degradation of organic compounds under solar light irradiation. Introduction: Cu2O nanomaterial is suitable for visible-light photocatalysis because the narrow band-gap (∼2.17 eV) allows it to absorb visible light. However, the morphological changes of Cu2O during photocatalysis have been rarely investigated. Methods: Porous Cu2O nanoshells (NSs) with a nearly 100% hollow structure were synthesized by a two-step addition of reducer. The synthesized NSs were characterized and employed for the photocatalysis of methyl orange (MO) in a neutral solution at 30 °C in air. Results: The Cu2O NSs exhibited high adsorption and good photocatalysis rates with respect to the degradation of MO. Certain new phenomena were observed upon photocatalysis. Nearly all the chemical bonds in MO were fractured; however, a portion of the sulfur-containing group in MO remained on the NSs. The morphology of the Cu2O NSs changed and a large amount of nano-debris was produced. Further experimental analysis indicated the presence of some nano-debris after adsorption- desorption equilibrium (ADE). A negligible amount of nano-debris appeared during the light irradiation of the Cu2O suspension in the absence of MO. The results obtained via X-ray diffraction (XRD), scanning transmission electron microscopy (STEM) and high-resolution transmission electron microscopy (HRTEM) proved that the nano-debris was composed of Cu2O, and essentially comprised nanosheets that were discarded from the Cu2O NSs. Conclusion: The porous NSs were composed of Cu2O nanosheets with exposed {111} facets, which resulted in their strong adsorption ability and catalysis performance for the degradation of MO. Light irradiation accelerated this interaction and led to the discarding of Cu2O nanosheets from the Cu2O NSs. Because of the strong interaction between Cu⁺ and S, a portion of the sulfur-containing group in MO remained on the NSs after photocatalysis.

Background: This paper proposes a technology for the production of monolayer graphene by an easy, acscessible, and non-toxic method. Methods: For the preparation of graphene, a combination of chemical and physical (ultrasonic) treatment of the original graphite precursor (purity >99%) was applied. The precursor of graphite is placed in a beaker with a solution of KOH or H2SO4. The mixtures were homogenized well and sonicated for 4h. The applied ultrasound has a power of 120 W, frequency 40 kHz. Due to the effects of ultrasound, complex processes take place in the solutions, which leads to the formation of superfine graphene. Better results were obtained at samples treated with 2n H2SO4. The physicochemical properties of the resulting graphene were characterized mainly by Raman spectroscopy, FT-IR, TEM, SEM, and electrical conductivity measurements. Results: Our research was focused mainly on the field of nanotechnology, in particular on the synthesis of graphene, which could be used as a coating on electrodes for supercapacitors. In this connection, three series of samples were developed in which the pristine graphite was treated with 2n H2SO4, 4n H2SO4, and 6n H2SO4, respectively, and their electrical properties were measured. Conclusion: The obtained graphene shows electrical resistivity 2-3 times lower than that of the precursor of pure graphite.

Background: In micro- and nano-electronic devices, there is often a high contact resistance between carbon nanotubes (CNTs) and metals, which leads to the heating of electronic devices and the loss of a large amount of energy. Doping will be used to improve the electrical contact performance between CNTs and metals. Significance: A simple and low-cost electroless deposition technique is used to prepare nickel-doped carbon nanotubes (CNT-Ni) under different doping conditions and explore the influence of different nickel (Ni) doped samples on the electrical contact properties of CNTs. Method: In this study, the transition metal Ni was chosen to prepare CNT-Ni by electroless deposition method using nickel chloride hexahydrate (NiCl2•6H2O) as a medium. The morphology and structure of treated CNTs were characterized through scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectrometer, and ultraviolet photoelectron spectrometer (UPS). The contact resistance between CNTs and metals was measured by inductance capacitance resistance (LCR) tester. Result: The morphological characterization results showed that the incorporated Ni nanoparticles had moderate particle size and good combination with CNTs. The structural characterization indicated that the core component of the doped nanoparticles was transition metal element Ni, and the doping type was P-type, with the significantly increased work function of the doped CNTs. And the average value of the contact resistance between the Ni-doped CNTs and the gold electrode decreased by nearly 71.63%. Conclusion: This doping method can be used to effectively reduce the contact resistance between CNTs and metals. The research on the preparation of CNT-Ni is of practical significance in reducing the heating of electronic devices in practical use and then improving the performance and service life of devices.

Background: Thiazolidinone-4-ones belong to important heterocyclic compounds because of their broad spectrum of biological activities. Several methods for the synthesis of 4- thiazolidinones are reported in the literature. The main synthetic route to synthesize 1,3-thiazolidin- 4-ones is the three-component reaction between amine, a carbonyl compound and a mercapto-acid. Objective: Dapsone-Cu supported on silica coated Fe3O4 (Fe3O4@SiO2-pr@dapsone-Cu) as a new heterogeneous nanoparticle catalyst was synthesized and the structure and morphology of this catalyst were characterized by Fourier transform infrared spectroscopy (FT-IR), Xray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), zeta potential, vibrating sample magnetometry (VSM) and thermal gravimetric analysis (TGA). The new synthesized catalyst was applied as an effective nanocatalyst for the synthesis of new derivatives of azo-linked thiazolidinones through one-pot multi-component reaction of various aromatic aldehydes, thioglycolic acid and 4- aminoazobenzene under solvent-free condition. Methods:A mixture of aldehyde, thioglycolic acid, 4-aminoazobenzene (1 mmol) and 0.05 g Fe3O4@SiO2@dapsone-Cu MNPs was stirred at room temperature under solvent-free condition. Results: A facile, green, new and efficient method for the synthesis of thiazolidine-4-ones through three component reaction of various aldehydes, thioglycolic acid and 4-aminoazobenzene in the presence of Fe3O4@SiO2-propyl@dapsone-Cu complex under solvent-free reaction was reported. Conclusion: This new procedure has notable advantages such as excellent yields, short reaction time, operational simplicity, easy work-up, eco-friendly and using a non-toxic catalyst. Also, the catalyst is easily recoverable in the presence of an enormous magnet and reused for six consecutive reaction cycles without significant loss of activity.

Background: Dengue is known as the most severe arboviral infection in the world spread by Aedes aegypti. However, conventional and laboratory-based enzyme-linked immunosorbent assays (ELISA) are the current approaches in detecting dengue virus (DENV), requiring skilled and well-trained personnel to operate. Therefore, the ultrasensitive and label-free technique of the Silicon Nanowire (SiNW) biosensor was chosen for rapid detection of DENV. Methods: In this study, a SiNW field-effect transistor (FET) biosensor integrated with a back-gate of the low-doped p-type Silicon-on-insulator (SOI) wafer was fabricated through conventional photolithography and Inductively Coupled Plasma – Reactive Ion Etching (ICP-RIE) for Dengue Virus type-2 (DENV-2) DNA detection. The morphological characteristics of back-gated SiNW-FET were examined using a field-emission scanning electron microscope supported by the elemental analysis via energy-dispersive X-ray spectroscopy. Results and Discussion: A complementary (target) single-stranded deoxyribonucleic acid (ssDNA) was recognized when the target DNA was hybridized with the probe DNA attached to SiNW surfaces. Based on the slope of the linear regression curve, the back-gated SiNW-FET biosensor demonstrated the sensitivity of 3.3 nAM-1 with a detection limit of 10 fM. Furthermore, the drain and back-gate voltages were also found to influence the SiNW conductance changed. Conclusion: Thus, the results obtained suggest that the back-gated SiNW-FET shows good stability in both biosensing applications and medical diagnosis throughout the conventional photolithography method.