Current Nanomaterials - Volume 7, Issue 2, 2022

Background: Biological synthesis via greener routes attained eclectic interest for research investigators due to its reliable, sustainable, eco-friendly, and non-toxic nature since numerous efforts have been made laterally with reflective applications by synthesizing diverse nanomaterials, including metals/metal oxides, hybrid, and bioinspired materials during the past era. Objective: The present review aims to report, update and uncover all the minutiae concerning two medicinal plant sources allied with diversified metal and non-metal nanoparticle synthesis through a greener approach. Methods: The ornamental, medicinal plants such as Catharanthus roseus and Moringa oleifera have been broadly studied for the synthesis of varied nanoparticles because of their innumerable secondary metabolites, which may act as bio-reducing and stabilizing agents synthesized by metallic/ metal oxides, and non-metallic precursors such as silver, gold, sulphur, copper oxide, iron oxide, ruthenium oxide nanoparticles by means of either leaf infusions or part/whole plant. Conclusion: This report highlights a phenomenon of exploiting different parts of these two plants with their widespread applications in varied scientific domains, which may act as a promising drug candidate for drug delivery mechanisms by means of a nano approach.

Background: The excessive application of carbamate and organophosphorus pesticides showed relatively high acute toxicity due to inhibition of acetylcholinesterase enzyme in the neural system of insects and mammals. Objective: This review aimed to assess the current outstanding performance of nanocomposite based enzyme-less electrochemical sensors toward the determination of organophosphorus and carbamate pesticides detection. Methods: Enzyme based electrochemical sensor (biosensor) and classical (chromatographic) methods have been used widely for the detection of organophosphorus and carbamate pesticides. However, instability related to enzymes and complex sample preparation, the need for highly trained manpower, and other numerous disadvantages associated with chromatographic techniques limit their application for pesticides detection in many conditions. Therefore, currently, nanocomposite based enzyme-less electrochemical sensors are a good alternative to enzyme-based sensors for many researchers. Results: The reviewed literature revealed that, nanocomposite based enzyme-less sensors with numerous advantages have shown a comparable sensitivity with enzyme-integrated sensor for pesticide detection. Conclusion: Currently nanocomposite materials are widely used for many applications, including the fabrication of promising sensors for pesticide detections. The promising sensing potential might be attributed to the special functional groups on the surface of the nanomaterials and their composite form, enabling them to substitute those expensive bio-recognition elements (enzymes) and used as non-bio-recognition elements for the detection of pesticides.

Nanotechnology is thriving these days and plays a great role in the expansion of biosensors. A range of nanomaterials is used in the growth of biosensors in order to boost the performance and sensitivity of biosensors. Nanomaterials like nanowire, nanoparticles, carbon nanotubes, quantum dots, etc., are helpful in increasing different properties like enzyme loading capacity, bioanalyte loading, good absorption as well as immobilization of enzymes. The skill of nanobiosensors becomes extra accurate and reliable as it allows quick selection of diverse analytes at little cost. The main target for nanobiosensor research includes the development of novel technologies in order to make improvements in the field of marker detection of human and animal disease, identification and study of therapeutic compounds, characterization of nano and bio-materials and the development of biocatalysts. This paper has reviewed basic principles and various nano-structure based biosensors along with their applications in different areas such as biomedical and forensic, environmental, agricultural and the food sector and recent advancements.

Background: Yttria Stabilized Zirconia (YSZ) is an attractive material which exhibits a characteristic combination of physical and chemical properties of YSZ in terms of inertness, resistant to corrosion, high mechanical strength, thermal stability, chemical stability and photostability. Because of these properties and applications, it is very important to synthesize yttrium stabilized zirconia (YSZ) powder. Till date, various preparative techniques have been reported for the synthesis of high porous YSZ nano powders. However, special equipment, long time with multistep processing, high calcination temperature, small surface area and low product yield are the usual drawbacks of most of the methods. Therefore. Solution Combustion Method (SCS) method has been established for the synthesis of YSZ nanopowder with high surface area. Objective: The main objective of our present research work is to effectively synthesized the Yttrium stabilized zirconia (YSZ) Zr0.72 Y0.28 O1.862 nanopowder by solution combustion method using yttrium nitrate (Y(NO3)3.6H2O), zirconyl nitrate (ZrO(NO3)2.XH3O) as oxidizers and ethylenediamine tetra acetic acid (EDTA) as a fuel and the synthesized powder was used in the application of photodegradation of dyes. Methods: YSZ nanopowder was synthesized by using Solution combustion synthesis. Solution combustion synthesis (SCS) is a simple exothermic self-sustaining one step chemical reaction, which will produce a large number of pores in the oxide material and inhibit their agglomeration leading to a large specific surface area and small crystallite size of the resulting material. Results and Discussion: Powder X-ray Diffraction (PXRD) revealed the formation of pure cubic phase of YSZ (Zr0.72 Y0.28 O1.862) nanopowder and the crystallite size of 15.4 nm was calculated by using Scherrer’s formula. The porous morphology of the product was observed by SEM images. BET surface area reveals that the relatively larger surface area of 87.17 m²g^-1. TEM analysis revealed uniform particle size distribution with average particle sizes varying in the range of 20-100 nm. The UV-Vis DRS spectrum was used to calculate the absorption wavelength (339 nm) and the corresponding band gap (3.72 eV) using Tauc plot. The photoluminescence spectrum of YSZ nanopowder showed an emission peak at 339 nm. The photodegradation (decolourisation) of methylene blue (MB) dye was increased from 75-90% with increase in the concentration of YSZ photocatalyst from 100 mg to 400 mg due to availability of OH radicals in the presence of UV radiation. The electrochemical studies using cyclic voltammetry reveal a substantial increase in current density of YSZ electrode from 0.0001A to 0.0005A when compared with bare carbon electrode and the instantaneous rise in redox current for the YSZ electrodes from 0.0001A to 0.0005A with increasing scan rate from 10 mVs-1 to 90 mVs^-1. Conclusion: In our reported work, we start a simple and rapid solution combustion synthetic approach to produce highly effective YSZ nanopowder using EDTA as organic fuel. Because of large surface area and small particle size of the YSZ nanopowder shows 85% of degradation of MB takes place in presence of UV light. In order to understand the electrochemical property of YSZ, the redox current measurement was carried out using cyclic voltametry and resulted that increase in redox current for the YSZ electrodes with increasing scan rate from 10 mVs-1 to 90 mVs^-1.

Background: The phenolic compounds are normally originating in together edible and nonedible plants, and they have been described several nanoscience based biological properties, containing antioxidant movement. The phenolic compound is present in fruits, vegetables, leaves, tea, coffee, peels, wine, etc. Also, the obtained phenolic compounds from therapeutic herbs and nutritional plants include phenolic acids, flavonoids, tannins and other. In a corresponding path from last two decades, nanoscience has wide application in extraction of bioactive components from various natural resources. Furthermore, nanomaterials have made significant contribution for the improvement of analytical techniques towards the collective objective to develop analytical recital and sustainability to developing new techniques for maintain the superiority assurance of food and beverages. Methods: In modern years, extraction and refining of bioactive composites as of natural sources proven excessive attention as they are used in various sectors such as foodstuffs, perfumery, cosmetics, paints and medicinal. Hence, separation of natural products and identification of new natural sources of bioactive compounds have increased methodical and industrialized significance. As the extraction and purification of these bioactive composites are the main steps to come across the rising demands. Results: The investigational outcomes confirm that the extracted phenolic compounds were maximally concentrated of 0.101 and 0.126 mg of GAE/g at speed of agitation (rpm) temperature°C respectively. Conclusion: In this study extraction of the phenolic compound was carried out from the Citrus Sinensis (Orange) powder by the stirred batch extraction and comparison with the traditional soxhlet extraction techniques.

Background: A Facile, scalable approach to fabrication of organic thin films with an embedded layer of nanoparticles in the ambient environment. The approach is based on step-bystep spin-coating of polymethylmethacrylate (PMMA) films and a nanoparticle layer. Objective: The goal of the present work is to fabricate a sandwich structure of the PMMA films for the top and bottom layers of a sandwich structure as well as a middle layer of nanoparticles formed in solution by the Laser Ablation in Liquid (LAL) method. Methods: First, a PMMA thin film was fabricated by spin-casting of PMMA solution in ethylacetate. Secondly, a solution of Au nanoparticles synthesized by laser ablation in ethanol was spin-cast on a prefabricated PMMA film. The distribution of Au nanoparticles and the morphology of the resulting film were analyzed using scanning electron microscopy (SEM), optical microscopy, and atomic microscopy (AFM). Finally, another PMMA layer was spin-cast on the nanoparticle-decorated film. Results: A hybrid organic film with the embedded layer of nanoparticles was fabricated using the spin-casting method for top and bottom layers as well as for the middle layer of Au nanoparticles fabricated by laser ablation in ethanol by a pulsed UV laser. Statistical and fractal analysis shows uniform distribution of nanoparticles on length scale above ten microns. Conclusion: Spin-cast-based layer-by-layer approach to fabrication of sandwich structures of organic films with embedded nanoparticlesis a facile and scalable method for hybrid organic - nanoparticle films. This approach can be extended for the fabrication of multi-layered hybrid structures.