Applications of nano-catalyst in new era

Plant-assisted green preparation of silver nanoparticles using leaf extract of Dalbergia sissoo and their antioxidant, antibacterial and catalytic applications

Plant-mediated preparation of silver nanoparticles (AgNPs) is thought to be a more economical and environmentally benign process in comparison to physical and chemical synthesis methods. In the present study, the aqueous leaf extract of Dalbergia sissoo was prepared and utilized to reduce silver ion (Ag+) during the green synthesis of silver nanoparticles (DL-AgNPs). The formation of DL-AgNPs was verified using UV-Vis spectra, exhibiting the surface plasmon resonance (SPR) band at around 450 nm. FT-IR analysis revealed the kinds of phytochemicals that serve as reducing and capping agents while DL-AgNPs are being synthesized. Analysis of scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HR-TEM) images verified the development of spherical and oval-shaped DL-AgNPs, with sizes ranging from 10 to 25 nm. The stability and particle size distribution of synthesized DL-AgNPs were ensured by zeta potential and DLS (dynamic light scattering) investigations. Additionally, X-ray diffraction (XRD) analysis confirmed the crystalline nature of DL-AgNPs. In antioxidant experiments, DL-AgNPs demonstrated significant scavenging capacities of DPPH and ABTS radicals with EC50 values of 51.32 and 33.32 μg/mL, respectively. The antibacterial activity of DL-AgNPs was shown to be significant against harmful bacteria, with a maximum zone of inhibition (21.5 ± 0.86 mm) against Staphylococcus aureus. Furthermore, DL-AgNPs exhibited effective catalytic activity to degrade environment-polluting dyes (methylene blue, methyl orange, and Congo red) and toxic chemicals (p-nitrophenol). The results of all these studies suggested that DL-AgNPs made from the leaf extract of Dalbergia sissoo have merit for application in the environmental and biomedical fields.

Unveiling the Impact of Eco-Friendly Synthesized Nanoparticles on Vegetative Growth and Gene Expression in Pelargonium graveolens and Sinapis alba L

Nanoscale geranium waste (GW) and magnesium nanoparticle/GW nanocomposites (Mg NP/GW) were prepared using green synthesis. The Mg NP/GW samples were subjected to characterization using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR-FT). The surface morphology of the materials was examined using a scanning electron microscope (SEM), and their thermal stability was assessed through thermal gravimetric analysis (TG). The BET-specific surface area, pore volume, and pore size distribution of the prepared materials were determined using the N2 adsorption-desorption method. Additionally, the particle size and zeta potentials of the materials were also measured. The influence of the prepared nanomaterials on seed germination was intensively investigated. The results revealed an increase in seed germination percent at low concentrations of Mg NP/GWs. Upon treatment with Mg NP/GW nanoparticles, a reduction in the mitotic index (MI) was observed, indicating a decrease in cell division. Additionally, an increase in chromosomal abnormalities was detected. The efficacy of GW and Mg NP/GW nanoparticles as new elicitors was evaluated by studying their impact on the expression levels of the farnesyl diphosphate synthase (FPPS1) and geranylgeranyl pyrophosphate (GPPS1) genes. These genes play a crucial role in the terpenoid biosynthesis pathway in Sinapis alba (S. alba) and Pelargonium graveolens (P. graveolens) plants. The expression levels were analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. The qRT-PCR analysis of FPPS and GPPS gene expression was performed. The outputs of FPPS1 gene expression demonstrated high levels of mRNA in both S. alba and P. graveolens with fold changes of 25.24 and 21.68, respectively. In contrast, the minimum expression levels were observed for the GPPS1 gene, with fold changes of 11.28 and 6.48 in S. alba and P. graveolens, respectively. Thus, this study offers the employment of medicinal plants as an alternative to fertilizer usage resulting in promoting environmental preservation, optimal waste utilization, reducing water consumption, and cost reduction.

Organosulphur and organoselenium compounds as ligands for catalytic systems in the Sonogashira coupling

Sonogashira coupling is a reaction of aryl/vinyl halides with terminal alkynes. It is used for the synthesis of conjugated enynes. Generally, copper (Cu) is required as a mediator for this reaction. It requires a long reaction time, high catalyst loading, or expensive ligands. Recently, homogeneous, heterogeneous, and nanocatalysts have been developed using organosulphur and organoselenium compounds as building blocks. Preformed complexes of metals with organosulphur and organoselenium ligands are used for homogeneous catalysis. Heterogeneous catalytic systems have also been developed using Cu, Pd, and Ni as metals. The nanocatalytic systems (synthesized using such ligands) include copper selenides and stabilized palladium(0) nanospecies. This article aims to cover the developments in the field of the processes and techniques used so far to generate catalytically relevant organic ligands having sulphur or selenium donor sites, the utility of such ligands in the syntheses of homogeneous, heterogeneous, and nanocatalytic systems, and critical analysis of their application in the catalysis of this coupling reaction. The results of catalysis are analyzed in terms of the effects of the S/Se donor, halogen atom of aryl halide, the effect of the presence/absence of electron-withdrawing or electron-donating groups or substituents on the aromatic ring of haloarenes/substituted phenylacetylenes, as well as the position (ortho or para) of the substitution. Substrate scope is discussed for all the kinds of catalysis. The supremacy of heterogeneous and nanocatalytic systems indicates promising future prospects.

Passive sweat wearable: A new paradigm in the wearable landscape toward enabling "detect to treat" opportunities

Growing interest over recent years in personalized health monitoring coupled with the skyrocketing popularity of wearable smart devices has led to the increased relevance of wearable sweat-based sensors for biomarker detection. From optimizing workouts to risk management of cardiovascular diseases and monitoring prediabetes, the ability of sweat sensors to continuously and noninvasively measure biomarkers in real-time has a wide range of applications. Conventional sweat sensors utilize external stimulation of sweat glands to obtain samples, however; this stimulation influences the expression profile of the biomarkers and reduces the accuracy of the detection method. To address this limitation, our laboratory pioneered the development of the passive sweat sensor subfield, which allowed for our progress in developing a sweat chemistry panel. Passive sweat sensors utilize nanoporous structures to confine and detect biomarkers in ultra-low sweat volumes. The ability of passive sweat sensors to use smaller samples than conventional sensors enable users with sedentary lifestyles who perspire less to benefit from sweat sensor technology not previously afforded to them. Herein, the mechanisms and strategies of current sweat sensors are summarized with an emphasis on the emerging subfield of passive sweat-based diagnostics. Prospects for this technology include discovering new biomarkers expressed in sweat and expanding the list of relevant detectable biomarkers. Moreover, the accuracy of biomarker detection can be enhanced with machine learning using prediction algorithms trained on clinical data. Applying this machine learning in conjunction with multiplex biomarker detection will allow for a more holistic approach to trend predictions. This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > Biosensing.

Molecular targets, therapeutic agents and multitasking nanoparticles to deal with cancer stem cells: A narrative review

There is increasing evidence that malignant tumors are initiated and maintained by a sub-population of tumor cells that have similar biological properties to normal adult stem cells. This very small population of Cancer Stem Cells (CSC) comprises tumor initiating cells responsible for cancer recurrence, drug resistance and metastasis. Conventional treatments such as chemotherapy, radiotherapy and surgery, in addition to being potentially toxic and non-specific, may paradoxically increase the population, spread and survival of CSCs. Next-generation sequencing and omics technologies are increasing our understanding of the pathways and factors involved in the development of CSCs, and can help to discover new therapeutic targets against CSCs. In addition, recent advances in nanomedicine have provided hope for the development of optimal specific therapies to eradicate CSCs. Moreover, the use of artificial intelligence and nano-informatics can elucidate new drug targets, and help to design drugs and nanoparticles (NPs) to deal with CSCs. In this review, we first summarize the properties of CSCs and describe the signaling pathways and molecular characteristics responsible for the emergence and survival of CSCs. Also, the location of CSCs within the tumor and the effect of host factors on the creation and maintenance of CSCs are discussed. Newly discovered molecular targets involved in cancer stemness and some novel therapeutic compounds to combat CSCs are highlighted. The optimum properties of anti-CSC NPs, including blood circulation and stability, tumor accumulation and penetration, cellular internalization, drug release, endosomal escape, and aptamers designed for specific targeting of CSCs are covered. Finally, some recent smart NPs designed for therapeutic and theranostic purposes to overcome CSCs are discussed.

Fast synthesis of [1,2,3]-triazole derivatives on a Fe/Cu-embedded nano-catalytic substrate

Triazoles are biologically important compounds that play a crucial role in biomedical applications. In this study, we present an innovative and eco-friendly nanocatalyst system for synthesizing compounds via the click reaction. The system is composed of Arabic gum (AG), iron oxide magnetic nanoparticles (Fe3O4 MNPs), (3-chloropropyl) trimethoxysilane (CPTMS), 2-aminopyridine (AP), and Cu(i) ions. Using AP as an anchor for Cu(i) ions and Fe3O4 MNPs allows facile separation using an external magnet. The hydrophilic nature of the Fe3O4@AG/AP-Cu(i) nanocomposite makes it highly efficient in water as a green solvent. The highest reaction efficiency (95.0%) was achieved in H2O solvent with 50.0 mg of nanocatalyst for 60 min at room temperature. The reaction yield remained consistent for six runs, demonstrating the stability and effectiveness of the catalyst.

Recent advances and progress in biotemplate catalysts for electrochemical energy storage and conversion

Complex structures and morphologies in nature endow materials with unexpected properties and extraordinary functions. Biotemplating is an emerging strategy for replicating nature structures to obtain materials with unique morphologies and improved properties. Recently, efforts have been made to use bio-inspired species as a template for producing morphology-controllable catalysts. Fundamental information, along with recent advances in biotemplate metal-based catalysts are presented in this review through discussions of various structures and biotemplates employed for catalyst preparation. This review also outlines the recent progress on preparation routes of biotemplate catalysts and discusses how the properties and structures of these templates play a crucial role in the final performance of metal-based catalysts. Additionally, the application of bio-based metal and metal oxide catalysts is highlighted for various key energy and environmental technologies, including photocatalysis, fuel cells, and lithium batteries. Biotemplate metal-based catalysts display high efficiency in several energy and environmental systems. Note that this review provides guidance for further research in this direction.

Hierarchical Interconnected NiMoN with Large Specific Surface Area and High Mechanical Strength for Efficient and Stable Alkaline Water/Seawater Hydrogen Evolution

NiMo-based nanostructures are among the most active hydrogen evolution reaction (HER) catalysts under an alkaline environment due to their strong water dissociation ability. However, these nanostructures are vulnerable to the destructive effects of H2 production, especially at industry-standard current densities. Therefore, developing a strategy to improve their mechanical strength while maintaining or even further increasing the activity of these nanocatalysts is of great interest to both the research and industrial communities. Here, a hierarchical interconnected NiMoN (HW-NiMoN-2h) with a nanorod-nanowire morphology was synthesized based on a rational combination of hydrothermal and water bath processes. HW-NiMoN-2h is found to exhibit excellent HER activity due to the accomodation of abundant active sites on its hierarchical morphology, in which nanowires connect free-standing nanorods, concurrently strengthening its structural stability to withstand H2 production at 1 A cm-2. Seawater is an attractive feedstock for water electrolysis since H2 generation and water desalination can be addressed simultaneously in a single process. The HER performance of HW-NiMoN-2h in alkaline seawater suggests that the presence of Na+ ions interferes with the reation kinetics, thus lowering its activity slightly. However, benefiting from its hierarchical and interconnected characteristics, HW-NiMoN-2h is found to deliver outstanding HER activity of 1 A cm-2 at 130 mV overpotential and to exhibit excellent stability at 1 A cm-2 over 70 h in 1 M KOH seawater.

Sustainable application of nanoparticles in wastewater treatment: Fate, current trend & paradigm shift

Existing water and wastewater treatment techniques are becoming increasingly difficult to employ due to the discovery of new toxins, the rapid development of population and industrial activities, and the limited quantity of water resources. Treatment of wastewater is a critical need in modern civilization due to a scarcity of water resources and rising industrial activity. Some of the techniques utilized include adsorption, flocculation, filtration, and others, although they are only used for primary wastewater treatment. However, the development and deployment of modern wastewater management with high efficiency and low capitalization are critical in terms of mitigating the environmental consequences of waste. The employment of different nanomaterials in the treatment of wastewater has opened up a world of possibilities for heavy metal and pesticide removal, as well as the treatment of microbes and organic contaminants in wastewater. Nanotechnology is a rapidly evolving technology because of certain nanoparticle's outstanding physiochemical and biological capabilities as contrasted to bulk counterparts. Secondly, it has been established that this is a cost-effective treatment strategy with significant potential in wastewater management, transcending the limitations imposed by currently existing technology. Advances in nanotechnology to reduce water contamination have been presented in this review, including the use of various nanomaterials such as nanocatalysts, nanoadsorbents, and nanomembranes in the treatment of wastewater containing organic contaminants, hazardous metals, and virulent pathogens.

Hybrid Magnetic Lipid-Based Nanoparticles for Cancer Therapy

Cancer is one of the major public health problems worldwide. Despite the advances in cancer therapy, it remains a challenge due to the low specificity of treatment and the development of multidrug resistance mechanisms. To overcome these drawbacks, several drug delivery nanosystems have been investigated, among them, magnetic nanoparticles (MNP), especially superparamagnetic iron oxide nanoparticles (SPION), which have been applied for treating cancer. MNPs have the ability to be guided to the tumor microenvironment through an external applied magnetic field. Furthermore, in the presence of an alternating magnetic field (AMF) this nanocarrier can transform electromagnetic energy in heat (above 42 °C) through Néel and Brown relaxation, which makes it applicable for hyperthermia treatment. However, the low chemical and physical stability of MNPs makes their coating necessary. Thus, lipid-based nanoparticles, especially liposomes, have been used to encapsulate MNPs to improve their stability and enable their use as a cancer treatment. This review addresses the main features that make MNPs applicable for treating cancer and the most recent research in the nanomedicine field using hybrid magnetic lipid-based nanoparticles for this purpose.

Biosynthesis of Silver Nanoparticles Using Salvia pratensis L. Aerial Part and Root Extracts: Bioactivity, Biocompatibility, and Catalytic Potential

The aim of this research was the synthesis of silver nanoparticles (SPA- and SPR-AgNPs) using the aqueous extracts of the aerial (SPA) and the root (SPR) parts of the plant Salvia pratensis L., their characterization, reaction condition optimization, and evaluation of their biological and catalytic activity. UV-Vis spectroscopy, X-ray powder diffraction (XRPD), scanning electron microscopy with EDS analysis (SEM/EDS), and dynamic light scattering (DLS) analysis were utilized to characterize the nanoparticles, while Fourier transform infrared (FTIR) spectroscopy was used to detect some functional groups of compounds present in the plant extracts and nanoparticles. The phenolic and flavonoid contents, as well as the antioxidant activity of the extracts, were determined spectrophotometrically. The synthesized nanoparticles showed twice-higher activity in neutralizing 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺) compared with the respective extracts. SPR-AgNPs exhibited strong antimicrobial activity against almost all of the tested bacteria (<0.0039 mg/mL) and fungal strains, especially against the genus Penicillium (<0.0391 mg/mL). Moreover, they were fully biocompatible on all the tested eukaryotic cells, while the hemolysis of erythrocytes was not observed at the highest tested concentration of 150 µg/mL. The catalytic activity of nanoparticles toward Congo Red and 4-nitrophenol was also demonstrated. The obtained results confirm the possibility of the safe application of the synthesized nanoparticles in medicine and as a catalyst in various processes.

Palladium Nanoparticles on Chitosan-Coated Superparamagnetic Manganese Ferrite: A Biocompatible Heterogeneous Catalyst for Nitroarene Reduction and Allyl Carbamate Deprotection

Although metallic nanocatalysts such as palladium nanoparticles (Pd NPs) are known to possess higher catalytic activity due to their large surface-to-volume ratio, however, in nanosize greatly reducing their activity due to aggregation. To overcome this challenge, superparamagnetic chitosan-coated manganese ferrite was successfully prepared and used as a support for the immobilization of palladium nanoparticles to overcome the above-mentioned challenge. The Pd-Chit@MnFe₂O₄ catalyst exhibited high catalytic activity in 4-nitrophenol and 4-nitroaniline reductions, with respective turnover frequencies of 357.1 min^-1 and 571.4 min^-1, respectively. The catalyst can also be recovered easily by magnetic separation after each reaction. Additionally, the Pd-Chit@MnFe₂O₄ catalyst performed well in the reductive deprotection of allyl carbamate. Coating the catalyst with chitosan reduced the Pd leaching and its cytotoxicity. Therefore, the catalytic activity of Pd-Chit@MnFe₂O₄ was proven to be unrestricted in biology conditions.

Bioremediations analysis using multifactorial porous materials derived from tea residue

Titanium dioxide nanoparticles (TiO₂ NPs) are becoming more and more renowned as biocompatible nanomaterials with diverse biological functions. In the present study, the aqueous extract of tea residue (tea filtered waste powder) was used to synthesize the TiO₂ NPs and treated for effluent bioremediations. Maximum absorption in the UV-Vis spectrum of the TiO₂ NPs was seen at 358 nm, and the XRD pattern reveals peaks at 2 h values of 25.78, 38.24, 47.98, 54.76, 55.32, 62.64, 69.05, 70.15, 75.24, and 83.59 that may be indexed to the (101), (004), (200), (105), (211), (204), (116), (220), (215) and (303). The FT-IR spectra of TiO₂ NPs showed a peak at 3420, 2925, 1621, 1382, 1098, and 687 cm-1. The spherical form and size were disclosed by FE-SEM analyses, and the EDAX pattern verified the purity of the TiO₂ NPs. The average particles size of the TiO₂ NPs was 32 nm. The photodegradation of paper mill waste water is significantly deteriorated up to 99.08% for 600 min, but textile waste water is degraded up to 98.06% for the same duration. Furthermore, we reported that TiO₂ NPs may rapidly breakdown industrially hazardous effluents when exposed to sunshine. Overall, this new, straightforward, and environmentally beneficial strategy may be of interest to the management of efficient degradation of dye solutions in the polluted regions.

Nanomaterials as a Sustainable Choice for Treating Wastewater: A Review

The removal of dyes from textile effluents utilizing advanced wastewater treatment methods with high efficiency and low cost has received substantial attention due to the rise in pollutants in water. The purpose of this work is to give a comprehensive analysis of the different treatments for removing chemical dyes from textile effluents. The capability and potential of conventional treatments for the degradation of dyeing compounds in aqueous media, as well as the influence of multiple parameters, such as the pH solution, initial dye concentration, and adsorbent dose, are presented in this study. This study is an overview of the scientific research literature on this topic, including nanoreductive and nanophotocatalyst processes, as well as nanoadsorbents and nanomembranes. For the purpose of treating sewage, the special properties of nanoparticles are currently being carefully researched. The ability of nanomaterials to remove organic matter, fungus, and viruses from wastewater is another benefit. Nanomaterials are employed in advanced oxidation techniques to clean wastewater. Additionally, because of their small dimensions, nanoparticles have a wide effective area of contact. Due to this, nanoparticles' adsorption and reactivity are powerful. The improvement of nanomaterial technology will be beneficial for the treatment of wastewater. This report also offers a thorough review of the distinctive properties of nanomaterials used in wastewater treatment, as well as their appropriate application and future possibilities. Since only a few types of nanomaterials have been produced, it is also important to focus on their technological feasibility in addition to their economic feasibility. According to this study, nanoparticles (NPs) have a significant adsorption area, efficient chemical reactions, and electrical conductivity that help treat wastewater effectively.

Evaluation the performance of the tin (IV) oxide (SnO2) in the removal of sulfur compounds via oxidative-extractive desulfurization process for production an eco-friendly fuel

Catalysts play a vital role in petroleum and chemical reactions. Intensified concerns for cleaner air with strict environmental regulations on sulfur content in addition to meet economic requirements have generated significant interests for the development of more efficient and innovative oxidative catalysts recently. In this study, a novel homemade nano catalyst (manganese oxide (MnO2) over tin (IV) oxide (SnO2)) was used for the first time as an effective catalyst in removing dibenzothiophene (DBT) from kerosene fuel using hydrogen peroxide (H2O2) as oxidant in catalytic oxidative-extractive desulfurization process (OEDS). The catalyst was prepared by impregnation method with various amount of MnO2 loaded on SnO2. The oxidation step was carried out at different operating parameters such as reaction temperature and reaction time in batch reactor. The extractive desulfurization step was performed by using acetonitrile as solvent under several operating conditions (agitation speed and mixing time). The activity of MnO2/SnO2 catalyst in removing various sulfur compounds from kerosene fuel at the best operating conditions was investigated in this work. The results of the catalyst characterization proved that a high dispersion of MnO2 over the SnO2 was obtained. The experiments showed that the highest DBT and various sulfur compounds removal efficiency from kerosene fuel under the best operating conditions (oxidation: 5% MnO2/SnO2, reaction temperature of 75 °C, and reaction time of 100 min, extraction: acetonitrile, agitation speed of 900 rpm, and mixing time of 30 min) via the catalytic oxidative-extractive desulfurization process was 92.4 and 91.2%, respectively. Also, the MnO2/SnO2 catalyst activity was studied after six consecutive oxidation cycles at the best operating conditions, and the catalyst prove satisfactory stability in terms of sulfur compounds removal. After that, the spent catalyst were regenerated by utilizing different solvents (methanol, ethanol and iso-octane), and the experimental data explained that iso-octane achieved highest regeneration efficiency.

Green synthesis of copper oxide and manganese oxide nanoparticles from watermelon seed shell extract for enhanced photocatalytic reduction of methylene blue

In the current study, copper oxide (CuO) and manganese oxide (MnO) nanoparticles (NPs) were synthesized through a simple, cost-efficient, and green method using watermelon seed shell extract as a stabilizing and reducing agent. The synthesized CuO and MnO NPs were characterized by using scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and Ultraviolet spectroscopy (UV). The particle sizes of CuO and MnO NPs were determined to be in the range of 15-97 and 6-51 nm, respectively, by TEM and XRD analysis. The photocatalytic performance of the CuO and MnO NPs used as catalysts were investigated for the photocatalytic reduction of methylene blue in an aqueous solution. In the photocatalytic reduction of methylene blue, sodium borohydride (NaBH₄) was used as the reducing agent. The CuO and MnO NPs were capable to remove 96.58% (in 70 min) and 96.60% (in 140 min) of methylene blue from aqueous media, respectively. Besides, the kinetics of the photocatalytic reaction was investigated by a pseudo-first order model, and the reaction rate coefficient for methylene blue with CuO and MnO NPs were calculated as 0.0426 and 0.0235 min^-1, respectively. The results demonstrated that the synthesized CuO and MnO NPs through the green method were promising catalysts to improve the photocatalytic reduction performance of methylene blue.

Biologically Synthesized Copper Nanoparticles Show Considerable Degradation of Reactive Red 81 Dye: An Eco-Friendly Sustainable Approach

Diospyros kaki leaf extract was used in this study as a favorable basis for the synthesis of copper nanoparticles (Cu NPs). X-ray diffraction (XRD) and UV-visible spectroscopy approaches were used to characterize the biologically synthesized copper nanoparticles. The XRD analysis showed that copper nanoparticles were face-centered cubic structure. Various experimental levels like conc. of dye, concentration of Cu NPs, pH, reaction time, and temperature were optimized to decolorize reactive red 81 dye using the synthesized Cu NPs. Reactive red 81 dye was decolorized maximum using Cu NPs of 0.005 mg/L. Additionally, reactive red 81 dye was decolorized at its maximum at pH = 6, temperature = 50°C. Our study reported that chemical oxidation demand (COD) and total organic carbon (TOC) deduction efficacies were 74.56% and 73.24%. Further degradation study of reactive red 81 dye was also carried out. Cu NPs have the ability and promising potential to decolorize and degrade reactive red 81 dye found in wastewater.

Self-propelled micro/nanobots: A new insight into precisely targeting cancerous cells through intelligent and deep cancer penetration

Cancer overlooks are globally one of the most dangerous and life-threatening tribulations. While significant advances have been made in the targeted delivery of anti-cancer medications over the last few years, several challenges, such as low efficacy and strong toxic effects, remain to be addressed. Micro/nanomotors have been thoroughly studied for both effective cancer detection and treatment, as demonstrated by significant advancements in the architecture of smart and functional micro/nanomotor biomedical systems. Able to self-propelled within fluid media, micro/nanomotors have attractive vehicles to maximize the efficacy of tumor delivery. Here, we present the current developments in the delivery, detection, and imaging-guided treatment of micro/nanomotors in the clinical field, including cancer-related specific targeted drug delivery, and then discuss the barriers and difficulties encountered by micro/nanomotors throughout the medical process. Furthermore, this paper addresses the potential growth of micro/nanomotors for medical applications, and sets out the current drawbacks and future research directions for more advancement.

Fast and effective catalytic degradation of an organic dye by eco-friendly capped ZnS and Mn-doped ZnS nanocrystals

Undoped and manganese doped ZnS nanocrystals encapsulated with thioglycolic acid (ZnS-TGA) were synthesized and characterized with different techniques, and finally tested in the photodegradation of a methyl orange in aqueous solution under UV and sunlight irradiations. FTIR and X-ray diffraction results confirmed the functionalization of these nanocrystal surface by thioglycolic acid and the formation of crystalline structures of ZnS and Mn-doped ZnS with cubic and hexagonal phases. Calculated average size of ZnS nanocrystals was in the range of 2-3 nm. It was observed a blue shift of the absorbance threshold and the estimated bandgap energies were higher than that of Bulk ZnS thus confirming the quantum confinement effect of charge carriers. Photoluminescence spectra of ZnS nanocrystals exhibited emission in the range of 410-490 nm and the appearance of an additional emission band around 580 nm (2.13 eV) connected to the ⁴T₁ → ⁶A₁ transition of the Mn²⁺ions. Photodegradation of methylene orange with undoped and Mn-doped ZnS-TGA nanocrystals was investigated. Dye adsorption prior to photocatalysis using nanocrystals was studied via kinetic and equilibrium experiments. The maximum dye adsorption capacity on doped ZnS-TGA was ~ 26.98 mg/g. The adsorption kinetic was found to follow the pseudo-second-order kinetic model. A statistical physics model was used to analyze the equilibrium data where the calculated adsorption energy was 17-18 kJ/mol. It was concluded that the dye adsorption was associated to the hydrogen interaction where the removal process was feasible and multi-molecular at 25 °C. The photocatalytic activity of undoped ZnS nanoparticles under UV irradiation showed better efficiency than doped nanocrystals thus indicating that manganese doping generated a dropping of the photocatalytic degradation of the dye. Dye degradation efficiency of 81.37% using ZnS-TGA nanocrystals was achieved after 6 min, which indicated that ZnMnS-TGA nanocrystals may be considered an alternative low cost and environmental friendly material for facing water pollution caused by organic compounds via photodegradation processes.

Nanoarchitectured Cu based catalysts supported on alginate/glycyl leucine hybrid beads for tainted water treatment

Water pollution reached worrying point due to different dye pollutants which demands an instant solution. One of the best ways to manage water pollutants is their reduction and decolorization to less-toxic and useful compounds. However, reduction process requires an effective, stable, and recyclable catalyst to reduce such pollutants more effectively. Metal nanoparticles (M⁰) are highly effective catalysts but separation of nanoparticles after reaction is difficult and requires a high-speed centrifugation. If loaded on polymer-beads, they can be easily separated from the reaction-mixture. Hearin, alginate/glycyl leucine (AGL) hybrid-beads were prepared, and copper nanoparticles (Cu⁰) were grown on it by simple process. M⁰/AGL bead catalysts were tested toward reducing various toxic compounds. Among all developed composite-beads, the catalytic performance of Cu⁰/AGL was highest in terms of reduction kinetics. After initial screening for different pollutants, Cu⁰/AGL was much more effective for MO reduction, thus, all optimized different parameters i.e., catalyst dosage, stability, amount of reducing-agent and recyclability were experimentally determined. The Cu⁰/AGL showed high-rate constants (k_app) of 0.7566 and 2.9506 min^-1 depending on beads content. The reusability of the Cu⁰/AGL catalysts up to the 7^th cycle has been checked. With the use of AGL as support for the Cu nanoparticles, not only the catalytic activity was retained for longer times during reusability, but it helped in their easy separation.

Single Atom Catalysts: An Overview of the Coordination and Interactions with Metallic Supports

Catalyst utilization is a key economic factor in heterogeneous catalysis, particularly, when noble metals are used as the active phase. A huge saving on catalyst cost can be achieved with developing a single atomic layer of the active catalyst on a given cheap support. Besides the economic benefit, single atom catalysts (SACs) have also shown superior activity and selectivity relative to catalytic particles or nanoparticles; yet they are prone to aggregation and deactivation. The development of effective, stable, and commercially viable SACs is still a huge challenge. One of the remaining key obstacles is the ability to easily and effectively tune SACs-support interactions and coordination in a way that enables the production of robust, stable, and versatile SACs. Accordingly, the coordination and interactions between metallic supports and SACs and their impacts on SACs stability and activity are reviewed in this article.

Nanomaterials for Remediation of Environmental Pollutants

Today, environmental contamination is a big concern for both developing and developed countries. The primary sources of contamination of land, water, and air are extensive industrialization and intense agricultural activities. Various traditional methods are available for the treatment of different pollutants in the environment, but all have some limitations. Due to this, an alternative method is required which is effective and less toxic and provides better outcomes. Nanomaterials have attracted a lot of interest in terms of environmental remediation. Because of their huge surface area and related high reactivity, nanomaterials perform better in environmental clean-up than other conventional approaches. They can be modified for specific uses to provide novel features. Due to the large surface-area-to-volume ratio and the presence of a larger number of reactive sites, nanoscale materials can be extremely reactive. These characteristics allow for higher interaction with contaminants, leading to a quick reduction of contaminant concentration. In the present review, an overview of different nanomaterials that are potential in the remediation of environmental pollutants has been discussed.

Insights on sustainable approaches for production and applications of value added products

The increasing demand for the development of sustainable strategies to utilize and process agro-industrial residues paves new paths for exploring innovative approaches in this area. Biotechnology based microbial transformations provide efficient, low cost and sustainable approaches for the production of value added products. The use of organic rich residues opens new avenues for the production of enzymes, pigments, biofuels, bioactive compounds, biopolymers etc. with vast industrial and therapeutic applications. Innovative technologies like strain improvement, enzyme immobilization, genome editing, morphological engineering, ultrasound/supercritical fluid/pulse electric field extraction, etc. can be employed. These will be helpful in achieving significant improvement in qualitative and quantitative parameters of the finished products. The global trend for the valorisation of biowaste has boosted the commercialization of these products which has transformed the markets by providing new investment opportunities. The upstream processing of raw materials using microbes poses a limitation in terms of product development and recovery which can be overcome by modifying the bioreactor design, physiological parameters or employing alternate technologies which will be discussed in this review. The other problems related to the processes include product stability, industrial applicability and cost competitiveness which needs to be addressed. This review comprehensively discusses the recent progress, avenues and challenges in the approaches aimed at valorisation of agro-industrial wastes along with possible opportunities in the bioeconomy.

Algae as potential feedstock for various bioenergy production

Depletion of non-renewable feedstock and severe wastewater pollution due to human activities have created negative impact to living organisms. The potential solution is to implement wastewater treatment and bioelectricity production through algae-based microbial fuel cell. The algae biomass produced from microbial fuel cell could be further processed to generate biofuels through their unique compositions. The consumption of nutrients in wastewater through algae cultivation and biomass produced to be utilized for energy supply have showed the potential of algae to solve the issues faced nowadays. This review introduces the background of algae and mitigation of wastewater using algae as well as the bioenergy status in Malaysia. The mechanisms of nutrient assimilation such as nitrogen, phosphorus, carbon, and heavy metals are included, followed by the application of algae in microbial fuel cell's chambers. Lastly, the status of algae for bioenergy production are covered.

Synthesis, photocatalytic and antibacterial activities of a PDS-activated MgO nanocatalyst: experimental and theoretical studies

PDS activation of MgO nanoparticles provides the opportunity to explore their applications and activities.

Investigation of TiO2 Nanoparticles Synthesized by Sol-Gel Method for Effectual Photodegradation, Oxidation and Reduction Reaction

Metal oxide titanium dioxide (TiO2) nanoparticles were synthesized by using a simple and economical sol-gel method. The prepared nanoparticles were used to evaluate methylene blue dye degradation and as catalysts in the oxidation of benzaldehyde. The crystallite size of the titanium dioxide nanoparticle was 18.3 nm, which was confirmed by X-ray diffraction analysis. The spherical morphology was confirmed by scanning electron microscopy (SEM), and the elemental composition of the nanoparticle was found by energy dispersive X-ray (EDAX) analysis. The anatase form of the nanoparticle was confirmed by the bandgap 3.2 eV, which was measured using UV–DRS analysis. The bond between metal and oxygen was confirmed by the peaks at 485 and 606 cm–1 analyzed by Fourier transform infrared analysis (FTIR). The efficiency of the catalyst in dye degradation was 60.08, 68.38, and 80.89% with respect to 50, 75, and 100 mg catalyst weight. The yield % of benzoic acid was 94%, and the reduction efficiency against 4-nitrophenol was 98.44%.

Copper Nanoparticles as Growth Promoter, Antioxidant and Anti-Bacterial Agents in Poultry Nutrition: Prospects and Future Implications

Copper (Cu) is a vital trace mineral involved in many physiological functions of the body. In the poultry industry, copper sulfate is being used as a major source of Cu. Copper in the bulk form is less available in the body, and much of its amount excreted out with feces causing environmental pollution and economic loss. The application of nanotechnology offers promise to address these issues by making nanoparticles. Copper nanoparticles (Cu-NP) are relatively more bioavailable due to their small size and high surface to volume ratio. Although, there is limited research on the use of Cu-NP in the poultry industry. Some researchers have pointed out the importance of Cu-NP as an effective alternative of chemical, anti-bacterial agents, and growth promoters. The effect of Cu-NP depends on their size, dose rate and the synthesis method. Apart from there, high bioavailability Cu-NP exhibited positive effects on the immunity of the birds. However, some toxic effects of Cu-NP have also been reported. Further investigations are essentially required to provide mechanistic insights into the role of Cu-NP in the avian physiology and their toxicological properties. This review aims to highlight the potential effects of Cu-NP on growth, immune system, antioxidant status, nutrient digestibility, and feed conversion ratio in poultry. Moreover, we have also discussed the future implications of Cu-NP as a growth promoter and alternative anti-bacterial agents in the poultry industry.

Atomically Resolved Characterization of Optically Driven Ligand Reconfiguration on Nanoparticle Catalyst Surfaces

Dynamic ligand layers on nanoparticle surfaces could prove to be critically important to enhance the functionality of individual materials. Such capabilities could complement the properties of the inorganic component to provide multifunctionality or the ability to be remotely actuated. Peptide-based ligands have demonstrated the ability to be remotely responsive to structural changes when adsorbed to nanoparticle surfaces via incorporation of photoswitches into their molecular structure. In this contribution, direct spectroscopic evidence of the remote actuation of a photoswitchable peptide adsorbed onto Au nanoparticles is demonstrated using X-ray absorption fine structure spectroscopic methods. From this analysis, Au-X (X = C or N) coordination numbers confirm the changes before and after photoswitching in the surface ligand conformation, which was correlated directly to variations in the catalytic application of the materials for nitrophenol reduction processes. In addition, the catalytic application of the materials was demonstrated to be significantly sensitive to the structure of the nitrophenol substrate used in the reaction, suggesting that changes in the reactivity are likely based upon the peptide conformation and substrate structure. Such results confirm that surface ligands can be remotely reconfigured on nanoparticle surfaces, providing pathways to apply such capabilities to a variety of applications beyond catalysis ranging from drug delivery to sensing.

Metal Nanoparticles: a Promising Treatment for Viral and Arboviral Infections

Globally, viral diseases continue to pose a significant threat to public health. Recent outbreaks, such as influenza, coronavirus, Ebola, and dengue, have emphasized the urgent need for new antiviral therapeutics. Considerable efforts have focused on developing metal nanoparticles for the treatment of several pathogenic viruses. As a result of these efforts, metal nanoparticles are demonstrating promising antiviral activity against pathogenic surrogates and clinical isolates. This review summarizes the application of metal nanoparticles for the treatment of viral infections. It provides information on synthesis methods, size-related properties, nano-bio-interaction, and immunological effects of metal nanoparticles. This article also addresses critical criteria and considerations for developing clinically translatable nanosized metal particles to treat viral diseases.

Advanced biomedical applications of iron oxide nanostructures based ferrofluids

Ferrofluids or magnetic nanofluids are highly stable colloidal suspensions of magnetic nanoparticles (NPs) dispersed into various base fluids. These stable ferrofluids possess high thermal conductivity, improved thermo-physical properties, higher colloidal stability, good magnetic properties, and biocompatibility, which are the primary driving forces behind their excellent performance, and thus enable them to be used for a wide range of practical applications. The most studied and advanced ferrofluids are based on iron oxide nanostructures especially NPs, because of their easy and large-scale synthesis at low costs. Although in the last decade, several review articles are available on ferrofluids but mainly focused on preparations, properties, and a specific application. Hence, a collective and comprehensive review article on the recent progress of iron oxide nanostructures based ferrofluids for advanced biomedical applications is undeniably required. In this review, the state of the art of biomedical applications is presented and critically analyzed with a special focus on hyperthermia, drug delivery/nanomedicine, magnetic resonance imaging, and magnetic separation of cells. This review article provides up-to-date information related to the technological advancements and emerging trends in iron oxide nanostructures based ferrofluids research focused on advanced biomedical applications. Finally, conclusions and outlook of iron oxide nanostructures based ferrofluids research for biomedical applications are presented.

Applications of Green Synthesized Nanomaterials in Water Remediation

Water is the most important component on the earth for living organisms. With industrial development, population increase and climate change, water pollution becomes a critical issue around the world. Its contamination with different types of pollutants created naturally or due to anthropogenic activities has become the most concerned global environmental issue. These contaminations destroy the quality of water and become harmful to living organisms. A number of physical, chemical and biological techniques have been used for the purification of water, but they suffer in one or the other respect. The development of nanomaterials and nanotechnology has provided a better path for the purification of water. Compared to conventional methods using activated carbon, nanomaterials offer a better and economical approach for water remediation. Different types of nanomaterials acting as nanocatalysts, nanosorbents, nanostructured catalytic membranes, bioactive nanoparticles, nanomembranes and nanoparticles provide an alternative and efficient methodology in solving water pollution problems. However, the major issue with nanomaterials synthesized in a conventional way is their toxicity. In recent days, a considerable amount of research is being carried out on the synthesis of nanomaterials using green routes. Nanomaterials synthesized by using the green method are now being used in different technologies, including water remediation. The remediation of water by using nanomaterials synthesized by the green method has been reviewed and discussed in this paper.

Single molecule fluorescence imaging of nanoconfinement in porous materials

This review covers recent progress in using single molecule fluorescence microscopy imaging to understand the nanoconfinement in porous materials. The single molecule approach unveils the static and dynamic heterogeneities from seemingly equal molecules by removing the ensemble averaging effect. Physicochemical processes including mass transport, surface adsorption/desorption, and chemical conversions within the confined space inside porous materials have been studied at nanometer spatial resolution, at the single nanopore level, with millisecond temporal resolution, and under real chemical reaction conditions. Understanding these physicochemical processes provides the ability to quantitatively measure the inhomogeneities of nanoconfinement effects from the confining properties, including morphologies, spatial arrangement, and trapping domains. Prospects and limitations of current single molecule imaging studies on nanoconfinement are also discussed.

Ab Initiomodeling of Near-Edge EELS spectra for chemisorbed molecules

Electron energy loss spectroscopy (EELS) has recently been applied to probe chemisorbed molecules on metal nanostructures, but a fundamental understanding of the correlation between these spectra and the electronic structures of the adsorbates has been limited. We report here on the insights afforded by time-dependent density functional theory to decipher the energy loss near edge structure (ELNES) of EELS spectra associated with chemisorption. These first-principles calculations simulate the ELNES-EELS spectra for chemisorbed CO on various facets of Au and Pt. Computational predictions of key signatures such as the 'red shift' and reductions in the peak intensity of the 2π* and 6σ* peaks, as compared to free CO in the gas phase, are validated in comparison to experimentally collected EELS spectra. These signatures are revealed to arise from changes in the electronic structure in terms of unoccupied density of states associated with the chemisorption process. They are consistent with a Blyholder model that incorporates donation and back-donation of electrons. They are also characteristic of the chemisorption process, such as the choice of metal, site of adsorption and the coverage and distribution of adsorbates. Our simulations thus provide guidelines for the use of ELNES-EELS to characterize the atomic structure and adsorption property of nanostructured surfaces and facilitate the development of advanced nanomaterials for catalytic applications.

Stochastic Kinetics of Nanocatalytic Systems

Catalytic reaction events occurring on the surface of a nanoparticle constitute a complex stochastic process. Although advances in modern single-molecule experiments enable direct measurements of individual catalytic turnover events occurring on a segment of a single nanoparticle, we do not yet know how to measure the number of catalytic sites in each segment or how the catalytic turnover counting statistics and the catalytic turnover time distribution are related to the microscopic dynamics of catalytic reactions. Here, we address these issues by presenting a stochastic kinetics for nanoparticle catalytic systems. We propose a new experimental measure of the number of catalytic sites in terms of the mean and variance of the catalytic event count. By considering three types of nanocatalytic systems, we investigate how the mean, the variance, and the distribution of the catalytic turnover time depend on the catalytic reaction dynamics, the heterogeneity of catalytic activity, and communication among catalytic sites. This work enables accurate quantitative analyses of single-molecule experiments for nanocatalytic systems and enzymes with multiple catalytic sites.