Efficacy of Gold Nanoparticles against Drug-Resistant Nosocomial Fungal Pathogens and Their Extracellular Enzymes: Resistance Profiling towards Established Antifungal Agents

Microalgal biorefineries: Advancement in machine learning tools for sustainable biofuel production and value-added products recovery

The microalgae can be converted into biofuels, biochemicals, and bioactive compounds in a biorefinery. Recently, designing and executing more viable and sustainable biofuel production from microalgal biomass is one of the vital challenges in the development of biorefinery. Scalable cultivation of microalgae is mandatory for commercializing and industrializing the biorefinery. The intrinsic complication in cultivation of microalgae is the physiological and operational factors that renders challenging impact to enable a smooth and profitable operation. However, this aim can only be successful via a simulation prospect. Machine learning tools provides advanced approaches for evaluating, predicting, and controlling uncertainties in microalgal biorefinery for sustainable biofuel production. The present review provides a critical evaluation of the most progressing machine learning tools that validate a potential to be employed in microalgal biorefinery. These tools are highly potential for their extensive evaluation on microalgal screening and classification. However, the application of these tools for optimization of microalgal biomass cultivation in industries in order to increase the biomass production, is still in its initial stages. Integrated hybrid machine learning tools can aid the industries to function efficiently with least resources. Some of the challenges, and perspectives of machine learning tools are discussed. Besides, future prospects are also emphasized. Though, most of the research reports on machine learning tools are not appropriate to gather generalized information, standard protocols and strategies must be developed to design generalized machine learning tools. On a whole, this review offers a perspective information about digitalized microalgal exploitation in a microalgal biorefinery.

A review on immunoglobulin Y (IgY) conjugated with metal nanoparticles and biomedical uses

Today, the use of nanoparticles has attracted considerable attention in biomedical investigations and applications. Antibody-nanoparticle conjugates have proven to be useful tools for raising accuracy and sensitivity in in vitro diagnostics. IgY antibodies have benefits over different antibodies in terms of minimizing animal harm, reducing reactivity with mammalian factors, and cost-effective extraction. Metal nanoparticles are widely used for various medical and biological applications and are potential candidates for identifying pathogens and treating them, which can be mostly related to their special properties, including their shape and size. Avian IgY antibodies conjugated with nanoparticles have been widely used for the detection of parasitic, viral, and bacterial infections as well as allergens and toxicological and pharmaceutical molecules. This review aimed to investigate avian antibodies conjugated with metal nanoparticles and their biological applications.

Advances in gum-based hydrogels and their environmental applications

Gum-based hydrogels (GBHs) have been widely employed in diverse water purification processes due to their environmental properties, and high absorption capacity. More desired properties of GBHs such as biodegradability, biocompatibility, material cost, simplicity of manufacture, and wide range of uses have converted them into promising materials in water treatment processes. In this review, we explored the application of GBHs to remove pollutants from contaminated waters. Water resources are constantly being contaminated by a variety of harmful effluents such as heavy metals, dyes, and other dangerous substances. A practical way to remove chemical waste from water as a vital component is surface adsorption. Currently, hydrogels, three-dimensional polymeric networks, are quite popular for adsorption. They have more extensive uses in several industries, including biomedicine, water purification, agriculture, sanitary products, and biosensors. This review will help the researcher to understand the research gaps and drawbacks in this field, which will lead to further developments in the future.

Inorganic Nanoparticles: Tools to Emphasize the Janus Face of Amphotericin B

Amphotericin B is the oldest antifungal molecule which is still currently widely used in clinical practice, in particular for the treatment of invasive diseases, even though it is not devoid of side effects (particularly nephrotoxicity). Recently, its redox properties (i.e., both prooxidant and antioxidant) have been highlighted in the literature as mechanisms involved in both its activity and its toxicity. Interestingly, similar properties can be described for inorganic nanoparticles. In the first part of the present review, the redox properties of Amphotericin B and inorganic nanoparticles are discussed. Then, in the second part, inorganic nanoparticles as carriers of the drug are described. A special emphasis is given to their combined redox properties acting either as a prooxidant or as an antioxidant and their connection to the activity against pathogens (i.e., fungi, parasites, and yeasts) and to their toxicity. In a majority of the published studies, inorganic nanoparticles carrying Amphotericin B are described as having a synergistic activity directly related to the rupture of the redox homeostasis of the pathogen. Due to the unique properties of inorganic nanoparticles (e.g., magnetism, intrinsic anti-infectious properties, stimuli-triggered responses, etc.), these nanomaterials may represent a new generation of medicine that can synergistically enhance the antimicrobial properties of Amphotericin B.

Advances of liposomal mediated nanocarriers for the treatment of dermatophyte infections

Due to the adverse effects associated with long-term administration of antifungal drugs used for treating dermatophytic lesions like tinea unguium, there is a critical need for novel antifungal therapies that exhibit improved absorption and minimal adverse effects. Nanoformulations offer a promising solution in this regard. Topical formulations may penetrate the upper layers of the skin, such as the stratum corneum, and release an appropriate amount of drugs in therapeutic quantities. Liposomes, particularly nanosized ones, used as topical medication delivery systems for the skin, may have various roles depending on their size, lipid and cholesterol content, ingredient percentage, lamellarity, and surface charge. Liposomes can enhance permeability through the stratum corneum, minimize systemic effects due to their localizing properties, and overcome various challenges in cutaneous drug delivery. Antifungal medications encapsulated in liposomes, including fluconazole, ketoconazole, croconazole, econazole, terbinafine hydrochloride, tolnaftate, and miconazole, have demonstrated improved skin penetration and localization. This review discusses the traditional treatment of dermatophytes and liposomal formulations. Additionally, promising liposomal formulations that may soon be available in the market are introduced. The objective of this review is to provide a comprehensive understanding of dermatophyte infections and the role of liposomes in enhancing treatment.

Progresses in lignin, cellulose, starch, chitosan, chitin, alginate, and gum/carbon nanotube (nano)composites for environmental applications: A review

Water sources are becoming increasingly scarce, and they are contaminated by industrial, residential, and agricultural waste-derived organic and inorganic contaminants. These contaminants may pollute the air, water, and soil in addition to invading the ecosystem. Because carbon nanotubes (CNTs) can undergo surface modification, they can combine with other substances to create nanocomposites (NCs), including biopolymers, metal nanoparticles, proteins, and metal oxides. Furthermore, biopolymers are significant classes of organic materials that are widely used for various applications. They have drawn attention due to their benefits such as environmental friendliness, availability, biocompatibility, safety, etc. As a result, the synthesis of a composite made of CNT and biopolymers can be very effective for a variety of applications, especially those involving the environment. In this review, we reported environmental applications (including removal of dyes, nitro compounds, hazardous materialsو toxic ions, etc.) of composites made of CNT and biopolymers such as lignin, cellulose, starch, chitosan, chitin, alginate, and gum. Also, the effect of different factors such as the medium pH, the pollutant concentration, temperature, and contact time on the adsorption capacity (AC) and the catalytic activity of the composite in the reduction or degradation of various pollutants has been systematically explained.

Chitosan-supported metal nanocatalysts for the reduction of nitroaromatics

The second most abundant natural polymer in the earth's crust is chitosan (CS). The unique physical, chemical, structural, and mechanical features of this natural polymer have led to its increased application in a variety of fields such as medicine, catalysis, removal of pollutants, etc. To eliminate various pollutants, it is preferable to employ natural compounds as their use aids the removal of contaminants from the environment. Consequently, employing CS to eliminate contaminants is a viable choice. For this aim, CS can be applied as a template and support for metal nanoparticles (MNPs) and prevent the accumulation of MNPs as well as a reducing and stabilizing agent for the fabrication of MNPs. Among the pollutants present in nature, nitro compounds are an important and wide category of biological pollutants. 4-Nitrophenol (4-NP) is one of the nitro pollutants. There are different ways for the removal of 4-NP, but the best and most effective method for this purpose is the application of a metallic catalyst and a reducing agent. In this review, we report the recent developments regarding CS-supported metallic (nano)catalysts for the reduction of nitroaromatics such as nitrophenols, nitroaniline compounds, nitrobenzene, etc. in the presence of reducing agents. The metals investigated in this study include Ag, Au, Ni, Cu, Ru, Pt, Pd, etc.

Apoptotic, cytotoxic, antioxidant, and antibacterial activities of biosynthesized silver nanoparticles from nettle leaf

Here, we reported the biosynthesis of silver nanoparticles (AgNPs) using Urtica dioica (nettle) leaf extract as green reducing and capping agents and investigate their anticancer and antibacterial, activity. The Nettle-mediated biosynthesized AgNPs was characterized by UV-Vis a spectrophotometer. Their size, shape and elemental analysis were determined with the using of SEM and TEM. The crystal structure was determined by XRD and the biomolecules responsible for the reduction of Ag⁺ were determined using FTIR analysis. Nettle-mediated biosynthesis AgNPs indicated strong antibacterial activity against pathogenic microorganisms. Again, the antioxidant activity of AgNPs is quite high when compared to ascorbic acid. Anticancer effect of AgNPs, IC₅₀ dose was determined by XTT analysis using MCF-7 cell line and the IC₅₀ value was found to be 0.243 ± 0.014 μg/mL (% w/v).

A Review Unveiling Various Machine Learning Algorithms Adopted for Biohydrogen Productions from Microalgae

Biohydrogen production from microalgae is a potential alternative energy source that is now intensively being researched. The complex natures of the biological processes involved have afflicted the accuracy of traditional modelling and optimization, besides being costly. Accordingly, machine learning algorithms have been employed to overcome setbacks, as these approaches have the capability to predict nonlinear interactions and handle multivariate data from microalgal biohydrogen studies. Thus, the review focuses on revealing the recent applications of machine learning techniques in microalgal biohydrogen production. The working principles of random forests, artificial neural networks, support vector machines, and regression algorithms are covered. The applications of these techniques are analyzed and compared for their effectiveness, advantages and disadvantages in the relationship studies, classification of results, and prediction of microalgal hydrogen production. These techniques have shown great performance despite limited data sets that are complex and nonlinear. However, the current techniques are still susceptible to overfitting, which could potentially reduce prediction performance. These could be potentially resolved or mitigated by comparing the methods, should the input data be limited.

Nano-sized and microporous palladium catalyst supported on modified chitosan/cigarette butt composite for treatment of environmental contaminants

This study reports a versatile process for the fabrication of a microporous heterogeneous palladium nanocatalyst on a novel spherical, biodegradable, and chemically/physically resistant catalyst support consisting of chitosan (CS) and cigarette waste-derived activated carbon (CAC). The physicochemical properties of the microporous Pd-CS-CAC nanocatalyst developed were successfully determined by FTIR, XRD, FE-SEM, TEM, BET, and EDS techniques. TEM studies showed that the average particle size of the synthesized Pd NPs was about 30 nm. The catalytic prowess of microporous Pd-CS-CAC was evaluated in the reduction/decolorization of various nitroarenes (2-nitroaniline (2-NA), 4-nitroaniline (4-NA), 4-nitrophenol (4-NP), and 4-nitro-o-phenylenediamine (4-NPD)) and organic dyes (methyl red (MR), methyl orange (MO), methylene blue (MB), congo red (CR), and rhodamine B (RhB)) in an aqueous medium in the presence of NaBH₄ as the reducing agent at room temperature. The catalytic activities were studied by UV-Vis absorption spectroscopy of the supernatant at regular time intervals. The short reaction times, mild reaction conditions, high efficiency (100% conversion), easy separation, and excellent chemical stability of the catalyst due to its heterogeneity and reusability are the advantages of this method. The results of the tests showed that reduction/decolorization reactions were successfully carried out within 10-140 s due to the good catalytic ability of Pd-CS-CAC. Moreover, Pd-CS-CAC was reused for 5 consecutive times with no loss of the initial shape, size, and morphology, confirming that it was a sustainable and robust nanocatalyst.

Green synthesis of nanoparticles using botanicals and their application in management of fungal phytopathogens: a review

Green synthesis of nanoparticles is an emerging aspect in plant disease management that blends nanotechnology and plant-derived ingredients to produce a biocontrol formulation. Different physical and chemical processes employed in the synthesis of nanoparticles are polluting, expensive, and also release hazardous by- products. The range of secondary metabolites present in plants makes them efficient reducing and stabilizing agent during the synthesis process. These metabolites serve a vital role in plant defense against the invasion of phytopathogens including fungi, bacteria, viruses, insect pests, etc. The plant metabolites, such as sugars, terpenoids, polyphenols, alkaloids, phenolic acids, and proteins, have been shown to be crucial in the reduction of metal ions into nanoparticles. In green synthesis of nanoparticles, the plant extracts are used as potential reducing and capping. This also restricts the formation of clusters or aggregates and improves the colloidal stability. The nanoparticles exhibit excellent antimycotic against a variety of phytopathogens and are very efficient in managing plant diseases. The aim of this review is to highlight plants, phytochemicals exhibiting antifungal properties, green synthesis of nanoparticles using plant material and their antimycotic activity.

Powerful and fast nanostructure electrochemical sensor for monitoring of carbidopa catechol-based drug in water and biological fluids

Herein, to monitor the concentration of carbidopa in an aqueous solution, an analytical approach based on electrode surface modification by Pt/SWCNTs as a sensor has been proposed. Pt/SWCNTs was synthesized by polyol strategy and characterized by the TEM method. Results confirmed spherical Pt nanoparticles with a diameter of about 10 nm decorated at the surface of SWCNTs with good distribution. The carbon paste electrode modified (CPEM) with Pt/SWCNTs was fabricated by mixing 12% of nanocomposite as an optimum condition with graphite powder in the presence of paraffin oil as a binder. Carbidopa's oxidation signal was enhanced by about 2.73 times when using the CPEM/Pt/SWCNTs, and its oxidation potential was decreased by about 110 mV. Additionally, the sensor demonstrated a linear dynamic range of 1.0 nM-120 M with a detection limit of 0.5 nM at pH = 7.0 as the ideal condition for monitoring carbidopa. Therefore, carbidopa in water and dextrose saline can be detected using CPEM/Pt/SWCNTs with an acceptable recovery range.

Specific Focus on Antifungal Peptides against Azole Resistant Aspergillus fumigatus: Current Status, Challenges, and Future Perspectives

The prevalence of fungal infections is increasing worldwide, especially that of aspergillosis, which previously only affected people with immunosuppression. Aspergillus fumigatus can cause allergic bronchopulmonary aspergillosis and endangers public health due to resistance to azole-type antimycotics such as fluconazole. Antifungal peptides are viable alternatives that combat infection by forming pores in membranes through electrostatic interactions with the phospholipids as well as cell death to peptides that inhibit protein synthesis and inhibit cell replication. Engineering antifungal peptides with nanotechnology can enhance the efficacy of these therapeutics at lower doses and reduce immune responses. This manuscript explains how antifungal peptides combat antifungal-resistant aspergillosis and also how rational peptide design with nanotechnology and artificial intelligence can engineer peptides to be a feasible antifungal alternative.

Amin H, F. Alanazi S, Turki Jalil A, Khatami M, Mahmood Saleh M. Trace elements-based Auroshell gold@hematite nanostructure: Green synthesis and their hyperthermia therapy

Hyperthermia is an additional treatment method to radiation therapy/chemotherapy, which increases the survival rate of patients without side effects. Nowadays, Auroshell nanoparticles have attracted much attention due to their precise control over heat use for medical purposes. In this research, iron/gold Auroshell nanoparticles were synthesised using green nanotechnology approach. Auroshell gold@hematite nanoparticles were synthesised and characterised with rosemary extract in one step and the green synthesised nanoparticles were characterised by X-ray powder diffraction, SEM, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy analysis. Cytotoxicity of Auroshell iron@gold nanoparticles against normal HUVEC cells and glioblastoma cancer cells was evaluated by 2,5-diphenyl-2H-tetrazolium bromide method, water bath hyperthermia, and combined method of water bath hyperthermia and nano-therapy. Auroshell gold@hematite nanoparticles with minimal toxicity are safe against normal cells. The gold shell around the magnetic core of magnetite caused the environmental and cellular biocompatibility of these Auroshell nanoparticles. These magnetic nanoparticles with targeted control and transfer to the tumour tissue led to uniform heating of malignant tumours as the most efficient therapeutic agent.

Comparative Study of Antimicrobial Activity of Silver, Gold, and Silver/Gold Bimetallic Nanoparticles Synthesized by Green Approach

Nanotechnology is one of the most recent technologies. It is uncertain whether the production of small-size nanoparticles (NPs) can be achieved through a simple, straightforward, and medicinally active phytochemical route. The present study aimed to develop an easy and justifiable method for the synthesis of Ag, Au, and their Ag/Au bimetallic NPs (BNPs) by using Hippeastrum hybridum (HH) extract, and then to investigate the effects of Ag, Au, and their Ag/Au BNPs as antimicrobial and phytotoxic agents. Ag, Au, and their Ag/Au BNPs were characterized by UV-visible spectroscopy, FT-IR spectroscopy, XRD, EDX, and SEM analysis. XRD analysis conferring to the face of face-centered cubic crystal structure with an average size of 13.3, 10.72, and 8.34 nm of Ag, Au, and Ag/Au BNPs, respectively. SEM showed that Ag, Au, and Ag/Au BNPs had spherical morphologies, with calculated nano measurements of 40, 30, and 20 nm, respectively. The EDX analysis confirmed the composition of elemental Ag signal of the HH-AgNPs with 22.75%, Au signal of the HH-AuNPs with 48.08%, Ag signal with 12%, and Au signal with 38.26% of the Ag/Au BNPs. The Ag/Au BNPs showed an excellent antimicrobial efficacy against Gram-positive Staphylococcus aureus, Actinomycetes meriye, Bacillus cereus, Streptococcus pyogenes, Methicillin-resistant Staphylococcus aureus, Micrococcus luteus, Streptococcus pneumonia, and Gram-negative Klebsiella pneumonia, Escherichia coli, and Serratia marcescens bacterial strains, as well as against three fungal strains (Aspergillus niger, Aspergillus fumigatus, and Aspergillus flavus) compared to HH extract, HH-AgNPs, and HH-AuNPs. However, further investigations are recommended to be able to minimize potential risks of application.

Synthesis characterization of Zn-based MOF and their application in degradation of water contaminants

Metal-organic frameworks (MOFs) are currently popular porous materials with research and application value in various fields such as medicine and engineering. Aiming at the application of MOFs in photocatalysis, this paper mainly reviews the main synthesis methods of ZnMOFs and the latest research progress of Zn MOF-based photocatalysts to degrade organic pollutants in water, such as organic dyes. This nanomaterial is being used to treat wastewater and has proven to be very efficient because of its exceptionally large surface area and porous nature. The results show that Zn-MOFs are capable of high degradation of the above pollutants and over 90% of degradation was observed in publications. In addition, the reusability percentage was examined and studies showed that the Zn-MOF nanostructure has very good stability and can continue to degrade a high percentage of pollutants after several cycles. This review focuses on Zn-MOFs and their composites. First, the methods of synthesis and characterization of these compounds are given. Finally, the application of these composites in the process of photocatalytic degradation of dye pollutants such as methylene blue, methyl orange, crystal violet, rhodamine B, etc. is explained.

An intelligent DNA nanorobot for detection of MiRNAs cancer biomarkers using molecular programming to fabricate a logic-responsive hybrid nanostructure

Herein, we designed a DNA framework-based intelligent nanorobot using toehold-mediated strand displacement reaction-based molecular programming and logic gate operation for the selective and synchronous detection of miR21 and miR125b, which are known as significant cancer biomarkers. Moreover, to investigate the applicability of our design, DNA nanorobots were implemented as capping agents onto the pores of MSNs. These agents can develop a logic-responsive hybrid nanostructure capable of specific drug release in the presence of both targets. The prosperous synthesis steps were verified by FTIR, XRD, BET, UV-visible, FESEM-EDX mapping, and HRTEM analyses. Finally, the proper release of the drug in the presence of both target microRNAs was studied. This Hybrid DNA Nanostructure was designed with the possibility to respond to any target oligonucleotides with 22 nucleotides length.

Biosynthesis of silver nanoparticles using Lawsonia inermis and their biomedical application

Developing biosynthesis of silver nanoparticles (Ag‐NPs) using plant extract is an environmentally friendly method to reduce the use of harmful chemical substances. The green synthesis of Ag‐NPs by Lawsonia inermis extract and its cellular toxicity and the antimicrobial effect was studied. The physical and chemical properties of synthesised Ag‐NPs were investigated using UV‐visible spectroscopy, infrared spectroscopy, X‐ray diffraction (XRD), scanning, and transmission electron microscopy. The average size of Ag‐NPs was 40 nm. The XRD result shows peaks at 2θ = 38.07°, 44.26°, 64.43°, and 77.35° are related to the FCC structure of Ag‐NPs. Cytotoxicity of synthesised nanoparticles was evaluated by MTT toxicity test on breast cancer MCF7 cell line. Observations showed that the effect of cytotoxicity of nanoparticles on the studied cell line depended on concentration and time. The obtained IC₅₀ was considered for cells at a dose of 250 μg/ml. Growth and survival rates decreased exponentially with the dose. Antimicrobial properties of Ag‐NPs synthesised with extract were investigated against Escherichia coli, Salmonella typhimurium, Bacillus cereus, and Staphylococcus aureus to calculate the minimum inhibitory concentration and the minimum bactericidal concentration of (MBC). The results showed that the synthesised Ag‐NPs and the plant extract have antimicrobial properties. The lowest concentration of Ag‐NPs that can inhibit the growth of bacterial strains was 25 μg/ml.

Plant-mediated synthesis of silver-doped zinc oxide nanoparticles and evaluation of their antimicrobial activity against bacteria cause tooth decay

In this research, silver-doped zinc oxide (SdZnO) nanoparticles (NPs) were synthesized in an environmental-friendly manner. The synthesized NPs were identified by UV-vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Finally, the antimicrobial activity of synthesized ZnO and SdZnO NPs was performed. It was observed that by doping silver, the size of ZnO NPs was changed. By adding silver to ZnO NPs, the antimicrobial effect of ZnO NPs was improved. Antibacterial test against gram-positive bacterium Streptococcus mutants showed that SdZnO NPs with a low density of silver had higher antibacterial activity than ZnO NPs; Therefore, SdZnO NPs can be used as a new antibacterial agent in medical applications.

Effective treatment of resistant opportunistic fungi associated with immuno-compromised individuals using silver biosynthesized nanoparticles

Drug resistance in filamentous fungus to antifungal medicines is a huge problem in biomedical applications; so, an effective strategy for treating opportunistic fungal infections is needed. Mentha piperita is a very fascinating plant to treat a variety of ailments as home remedies. Eighteen strains of Aspergillus species were used for this study which are having a unique antifungal resistance profile in presence of silver nanoparticles (AgNPs). AgNPs were prepared, using an aqueous extract of M. Piperita and characterized it by various techniques. Structural properties of AgNPs were systematically studied using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and Raman measurement, which emanate the single-phase fcc structure of silver nanoparticles. The spherical nature and elemental analysis of as-synthesized AgNPs were confirmed using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy, respectively. The optical study has been analyzed using UV–Vis spectroscopy and band gap was calculated as 2.51 eV, using Tauc plot. To analyze and validate the good efficacy of the disc approach, antifungal activity of AgNPs nanoparticles in different concentrations against isolates was achieved in both disc and broth microdilution. The extracellular enzymatic activity of A. fumigatus was found to explore the precise impact of nanoparticles on fungal metabolism. The antifungal efficacy of AgNPs against all fungi was highly successful in disc method. The broth approach underlined the favorable results of the disc method. It provided more precise results in determining the minimum inhibition concentration (MIC), as well as the minimum effective concentration (MEC). A. fumigatus (AM6) enzymatic activity was boosted by AgNPs. Also, ß-galactosidase, ß-glucuronidase, and ß-glucosidase are necessary enzymes whose activity has been boosted. Consequently, M. piperita AgNPs can play a major and intriguing function against resistant Aspergillus species with a significant shift in the enzymatic activity profile of fungi due to this action.

A Cu(ii) complex supported on Fe3O4@SiO2 as a magnetic heterogeneous catalyst for the reduction of environmental pollutants

Today, the presence of pollutants in the environment has become one of the serious problems and concerns of human beings. To eliminate these pollutants, researchers have made many efforts. One of the most important of these efforts is the reduction of such contaminants in the presence of effective catalysts. Two of the most important and widespread types of these pollutants are nitro compounds and organic dyes. In this paper, we report the synthesis of an efficient and reusable magnetic catalyst using Fe₃O₄@SiO₂ core–shell nanoparticles (NPs), N-(4-bromophenyl)-N′-benzoylthiourea, and copper(ii). Specifically, the Cu(ii)-N-(4-bromophenyl)-N′-benzoylthiourea complex supported on Fe₃O₄-core magnetic NPs (CM)/SiO₂-shell (SS) (CM@SS-BBTU-Cu(ii)) has been prepared. CM@SS-BBTU-Cu(ii) was characterized by FT-IR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), TEM (transmission electron microscopy), HRTEM (high resolution transmission electron microscopy), FFT (fast Fourier transform), VSM (vibrating sample magnetometry), TG-DTA (thermogravimetry-differential thermal analysis), STEM (scanning transmission electron microscopy), EDS (energy-dispersive X-ray spectroscopy), and elemental mapping. The synthesized CM@SS-BBTU-Cu(ii) was applied for the reduction of 4-nitrophenol (4-NP), Congo red (CR), and methylene blue (MB) in the presence of NaBH₄ (sodium borohydride) at room temperature. CM@SS-BBTU-Cu(ii) can be recycled and reused 5 times. Our results displayed that the performance of the catalyst was not significantly reduced by recycling.

Nitro-aromatic-pollutants are hazardous to people and the environment. In this work, the catalytic potential of CM@SS-BBTU-Cu(ii) has been investigated for reduction of nitro group in aqueous media by NaBH₄.