Attarad Ali

Synthesis, characterization, applications, and challenges of iron oxide nanoparticles

Recently, iron oxide nanoparticles (NPs) have attracted much consideration due to their unique properties, such as superparamagnetism, surface-to-volume ratio, greater surface area, and easy separation methodology. Various physical, chemical, and biological methods have been adopted to synthesize magnetic NPs with suitable surface chemistry. This review summarizes the methods for the preparation of iron oxide NPs, size and morphology control, and magnetic properties with recent bioengineering, commercial, and industrial applications. Iron oxides exhibit great potential in the fields of life sciences such as biomedicine, agriculture, and environment. Nontoxic conduct and biocompatible applications of magnetic NPs can be enriched further by special surface coating with organic or inorganic molecules, including surfactants, drugs, proteins, starches, enzymes, antibodies, nucleotides, nonionic detergents, and polyelectrolytes. Magnetic NPs can also be directed to an organ, tissue, or tumor using an external magnetic field for hyperthermic treatment of patients. Keeping in mind the current interest in iron NPs, this review is designed to report recent information from synthesis to characterization, and applications of iron NPs.

Effect of ZnO Nanoparticles on Brassica nigra Seedlings and Stem Explants: Growth Dynamics and Antioxidative Response

Nanoparticles (NPs) have diverse properties when compared to respective chemicals due to their structure, surface to volume ratio, morphology, and reactivity. Toxicological effects of metallic NPs on organisms including plants have been reported. However, to the best of our knowledge, there is still not any report on the effect of NPs on in vitro culture of plant explants. In this study, ZnO NPs concentration ranging from 500 to 1500 mg/L adversely affects the Brassica nigra seed germination and seedling growth and also lead to an increase in the antioxidative activities and non-enzymatic antioxidants. While, culturing the stem explants of B. nigra on Murashige and Skoog (MS) medium at lower concentration of ZnO NPs (1–20 mg/L) resulted in the production of white thin roots with thick root hairs. At 10 mg/L ZnO NPs, shoots emergence is also observed. The developed calli/roots showed 79% DPPH (2,2-diphenyl-1-picryl hydrazyl) radical scavenging activity at 10 mg/L. The total antioxidant and reducing power potential also significantly affected in presence of ZnO NPs. Moreover, an increase in non-enzymatic antioxidative molecules, phenolics (up to 0.15 μg GAE/mg FW) and flavonoids (up to 0.22 μg QE/mg FW), depending on NPs concentration is also observed. We conclude that ZnO NPs may induce roots from explants cultured on appropriate medium that can be used for production of valuable secondary metabolites.

ZnO nanostructure fabrication in different solvents transforms physio-chemical, biological and photodegradable properties

Zinc oxide (ZnO) nanostructures are synthesized in various organic solvents (acetone, chloroform, ethyl acetate, ethanol and methanol) and water via coprecipitation process using zinc acetate as precursor. The resultant ZnO nanoparticles, nano rods and nano sheets are characterized by UV-vis spectrophotometric analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDX). The variable size and geometry of nanoparticles depend upon medium used for synthesis. The synthesized ZnO nanostructures exhibit minor to moderate antioxidative (DPPH based free radical scavenging activity, total antioxidative potential and total reducing power) response. Mild to moderate antibacterial and antifungal activities, excellent antileishmanial potential (IC50 up to 3.76), and good cytotoxic perspective (LD50 up to 49.4) is also observed by the synthesized ZnO NPs. The nanoparticles also exhibit moderate α-amylase inhibition response. Furthermore the nanostructures are evaluated for methylene blue photodegradation response within 60min time period. It is found that organic solvent alters shape, size and other physio-chemical properties of ZnO that ultimately modulate the biological, chemical, and environmental properties.

Investigation of Cu-containing low resistivity CdTe thin films deposited by the two-source evaporation technique

Cadmium telluride (CdTe) thin films were deposited onto scratch-free transparent glass substrates by the two-source evaporation technique, using Cd and Te as two different evaporants. In the next step, films were heated under vacuum at 500 ?C for 1 h and dipped in Cu(NO3)2?H2O solution at room temperature. These films were again heated under vacuum for 1 h at 500 ?C to obtain maximum Cu diffusion. The samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), optically by a Lambda 900 UV/VIS/NIR spectrophotometer and electrically, i.e. dc electrical resistivity, by the van der Pauw method at room temperature, dark conductivity, and activation energy analysis as a function of temperature by the two-probe method under vacuum. The EDX results showed an increase of Cu content in the samples by increasing the immersion time of the CdTe films in the solution. The layer thickness of diffused Cu atoms in CdTe is determined by comparing the difference of absorption between as-deposited and immersed films with the absorption graph of Cu films of varying thicknesses.

Synthesis of Ag-NPs impregnated cellulose composite material: its possible role in wound healing and photocatalysis

Cellulose is the natural biopolymer normally used as supporting agent with enhanced applicability and properties. In present study, cellulose isolated from citrus waste is used for silver nanoparticles (Ag-NPs) impregnation by a simple and reproducible method. The Ag-NPs fabricated cellulose (Ag-Cel) was characterised by powder X-rays diffraction, Fortier transform infrared spectroscopy and scanning electron microscopy. The thermal stability was studied by thermo-gravimetric analysis. The antibacterial activity performed by disc diffusion assay reveals good zone of inhibition against Staphylococcus aureus and Escherichia coli by Ag-Cel as compared Ag-NPs. The discs also displayed more than 90% reduction of S. aureus culture in broth within 150 min. The Ag-Cel discs also demonstrated minor 2,2-diphenyl 1-picryl-hydrazyl radical scavenging activity and total reducing power ability while moderate total antioxidant potential was observed. Ag-Cel effectively degrades methylene-blue dye up to 63.16% under sunlight irradiation in limited exposure time of 60 min. The Ag-NPs impregnated cellulose can be effectively used in wound dressing to prevent bacterial attack and scavenger of free radicals at wound site, and also as filters for bioremediation and wastewater purification.

Management of citrus waste by switching in the production of nanocellulose.

Citrus fruit processing industries produce a vast quantity of waste materials as peel and pulp that are not handled properly. In present study, waste generated from citrus has been used for extraction of cellulose and nanocellulose. The aggregated cellulose, derived after alkaline treatment, was acid hydrolysed; resulted in reduction of the size of cellulose fibre. The cellulose showed amorphous structure revealed by X-ray diffraction analysis. Scanning electron microscopy analysis explained densely packed structure of nanocellulose. High magnification revealed break points in cellulose fibre due to acidic treatment; looked like carbon nanotubes. The simple solubility test demonstrated that different solvents had different effects on the dissolution of nanocellulose. The study reveals that citrus peel is also a good candidate of cellulose that can be utilised for different applications.

Efficient metal adsorption and microbial reduction from Rawal Lake wastewater using metal nanoparticle coated cotton

This study was designed to investigate removal of toxic metals and reduction of bacterial count from Rawal Lake wastewater with novel nanocomposite sorbents. Iron, zinc and silver oxide nanoparticles (NPs) were attached on cotton. The nanocomposites (iron NPs on cotton (FeCt), zinc NPs on cotton (ZnCt) and silver NPs on cotton (AgCt)) were characterized by FTIR, XRD and SEM, which showed successful adsorption of 10-30 nm size nanoparticles. Batch experiments were performed to determine the adsorption capacity of nanocomposite for metal removal. All the three adsorbents demonstrated 100% adsorption efficiency for Ag+, Co2+, Fe3+, Zn2+ and Cu2+ whereas less adsorption for Cd2+ and Cr3+. The maximum adsorbance (qe) was exhibited by Co2+ on ZnCt, FeCt and AgCt as 125.0, 111.1 and 100.0 mg g-1, respectively. The efficiency of adsorbents for metal ions sorption was found as AgCt > ZnCt > FeCt while the order of adsorption for metals was observed as Fe3+ > Co2+ > Zn2+ > Cu2+ > Ag+ > Cr3+ > Cd2+. The adsorption mechanism mostly follow Langmuir isotherm and pseudo-second order kinetic model. The maximum microbial reduction was exhibited by AgCt followed by ZnCt and FeCt. The microbes were further processed for staining and biochemical characteristics to evaluate resistance and sensitive microbes. The study concludes that the NPs doped on cotton can be effectively used for adsorption of heavy metals and reduction of microbial count from natural wastewater making it valuable for human consumption. In addition, the nanoparticles impregnated cotton can be efficiently used in water filtration plants.

Elemental zinc to zinc nanoparticles: is ZnO NPs crucial for life? Synthesis, toxicological, and environmental concerns

Abstract The semi-conducting material zinc is one of the essential trace elements for humans, is a co-factor of more than 300 enzymes, and plays an important role in maintaining vital cellular functions. Deficiency of zinc may lead to cancer initiation; however, a high concentration also has toxic effects that might be life threatening. The toxicity can be addressed by the disequilibrium of zinc-mediated proteins and oxidative stress that produce nascent oxygen, hydroxyl radicals, and other reactive oxygen species. Zinc-based nanoparticles (NPs) are among the most important and multifunctional compounds. Zinc oxide (ZnO) NPs exhibit attractive antimicrobial and photocatalytic properties due to the smaller particle size and increased particle surface reactivity. Further, these are more biocompatible compared to other metallic NPs, easily synthesizable, and have high selectivity, enhanced cytotoxicity, and are a promising anticancer agent. However, some of the pertinent concerns regarding nano-zinc still needs to be clarified. Current research also demonstrates their usage in wastewater treatment, textile, medicine, etc. This review covers the importance of zinc for living systems and its NPs, with more emphasis on ZnO NPs. A comprehensive overview of ZnO NPs, their synthesis, characterization techniques, crystal structure, properties, and brief industrial applications are presented.

Nanomaterials as nanocarriers: a critical assessment why these are multi-chore vanquisher in breast cancer treatment

Abstract Breast cancer is a group of diseases with various subtypes and leads to high mortality throughout the globe. Various conventional techniques are in practice to cure breast cancer but these techniques are linked with various shortcomings. Mostly these treatments are not site directed and cause toxicity towards normal cells. In order to overcome these issues, we need smart system that can deliver anticancer drugs to specific sites. Targeted drug delivery can be achieved via passive or active drug delivery using nanocarriers. This mode of drug delivery is more effective against breast cancer and may help in the reduction of mortality rate. Potentially used nanocarriers for targeted drug delivery belong to organic and inorganic molecules. Various FDA approved nano products are in use to cure breast cancer. However, body’s defense system is main limitation for potential use of nano systems. However, this can be overcome by surface modification of nanocarriers. In this review, breast cancer and its types, targeted drug delivery and nanocarriers used to cure breast cancer are discussed. By progressing nanotechnology, we will be able to fight against this life threatening issue and serve the humanity, which is the basic aim of scientific knowledge.

Onosma bracteatum Wall and Commiphora stocksiana Engl extracts generate oxidative stress in Brassica napus: An allelopathic perspective

Abstract The use of synthetic chemicals as herbicides for crop protection is a big threat due to toxicity, non-degradability, and negative impact on environment. Onosma bracteatum leaves and flowers, and Commiphora stocksiana Engl bark ethanolic extracts are evaluated for allelopathic potential against Brassica napus, a model plant. Complete allelopathic tendency was depicted by crude extract of O. bracteatum leaves and partial trend by flower and C. stocksiana extracts. B. napus seed germination efficiency and plant architecture is adversely influenced by the presence of plants extracts. The antioxidative analysis of Brassica plants depicts that extracts in the growth environment produces oxidative stress that eventually increased free radical scavenging activity, total antioxidative potential, and reducing power capability. Though Brassica plants produced phenolics and flavonoids to combat the oxidative stress but at insufficient concentration. Based on the findings, it can be concluded that the plants extracts produce oxidative stress to the seedlings and plants that eventually results in toxicity and allelopathic effect. Furthermore O. bracteatum can be a good candidate for natural herbicide either in form of extracts or the allelopathic compounds isolated from this plant species, which can be used as replacement of expensive and harmful synthetic herbicide.