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Biomass valorization is essential, particularly in emerging countries. Here, hydrochar from arabica coffee straw was functionalized with a triazole group (HD-TRz) for use as a support of palladium nanoparticles (PdNPs-HD-TRz) applied in the Ullmann coupling reaction for the first time. It provided remarkably excellent selectivities, conversions at a temperature as low as 45 °C and catalyst recyclability, surpassing previous literature performances. Hydrochar was obtained by one-pot reaction via hydrothermal synthesis, using NaOH solution as activating agent and functionalized with a 1,3-triazole group by CuAAC "click" reaction. The PdNPs were prepared via reduction of hydrochar-bound Pd(II) using NaBH 4 . Hydrochar functionalization was monitored by infrared spectroscopy, and X-ray diffraction (XRD) allowed to observe carbon and palladium planes in hydrochar and PdNPs HD-TRz structures. The PdNPs presented a spherical shape with 2.1 ± 0.1 nm size, homogeneously distributed in the carbon coverslips. The HD-TRz-supported PdNPs were used as a catalyst in the Ullmann reaction of iodobenzene, using ethanol as solvent with 100% of conversion and 91% selectivity at 45 °C. The material was reused, presenting 100% of conversion and selectivities of 92, 84 and 73% for the 1st, 2nd and 3rd cycle, respectively. The scope of the reaction was expanded to other molecules showing the potential of this and other triazole-hydrochar-supported nanocatalysts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Electron transfer plays a major role in chemical reactions and processes, and this is particularly true of catalysis by nanomaterials. The advent of metal nanoparticle (NP) catalysts, recently including atomically precise nanoclusters (NCs) as parts of nanocatalyst devices has brought increased control of the relationship between NP and NC structures and their catalytic functions. Consequently, the molecular definition of these new nanocatalysts has allowed a better understanding and management of various kinds of electron transfer involved in the catalytic processes. This Minireview brings a chemist's view of several major aspects of electron-transfer functions concerning NPs and NCs in catalytic processes. Particular focus concerns the role of NPs and NCs as electron reservoirs and light-induced antenna in catalytic processes from H 2 generation to more complex reactions and sustainable energy production., (© 2021 Wiley-VCH GmbH.)

In this study, mycosynthesized zinc oxide nanoparticles (ZnONPs) are fabricated via Pleurotus sajor-caju mushroom extract, and their potential medical and environmental applications are demonstrated. The biosynthesized ZnONPs were assessed for their antibacterial, anticancer, and biodecolorization potential efficiency. They were also characterized and morphologically analyzed by UV-visible spectroscopy, XRD, FT-IR, FE-SEM, EDX, HR-TEM, Zeta potential, and GC-MS analysis. The UV visible spectrum analysis of synthesized ZnONPs analyzed outcome 354 nm was the SPR peak that the nanoparticles displayed. The characteristic Zn-O bond was indicated by a strong peak in the FT-IR study at 432.05 cm -1 . Based on XRD analysis, P. sajor-caju mediated ZnONPs were crystalline nature, with an average nano particle size of 14.21 nm and a polydispersity directory of 0.29. The nanoparticles exhibit modest constancy, as shown by their zeta potential value of - 33.2 mV. The presence of oxygen and zinc was verified by EDX analysis. The ZnONPs were found to be spherical in shape and crystalline nature structure, with smooth surface morphology and a mean particle size of 10 nm using HR-TEM and SAED analysis. The significant antibacterial activity against S. aureus (6.2 ± 0.1), S. mutans (5.4 ± 0.4), and B. subtilis (5.2 ± 0.1 mm) was demonstrated by the synthesized ZnONPs made using mushroom extract. It was discovered that when the concentration of mushroom extract was increased together with synthesized ZnONPs, the bactericidal activity increased considerably. A higher concentration of ZnONPs demonstrated superior antibacterial activity across the ZnONPs ratio tests. The in vitro cytotoxicity assay showed that ZnONPs, even at low doses, had a substantial number of cytotoxic effects on liver cancer cells (LC 50 values 47.42 µg/mL). The effectiveness test revealed that acid blue 129 was degraded. The best decolorization of acid blue 129 at 72.57% after 3 h of soaking serves as evidence for the theory that myco-synthesized ZnONPs by P. sajor-caju mushroom can function as catalysts in reducing the dye. The mycosynthesized ZnONPs from P. sajor-caju extract, and its potential for antibacterial, anticancer, and decolorization are in this investigation. The mycosynthesized ZnONPs suggest a novel use for nanoparticles in the creation of environmental and medicinal products., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Dopamine (DA) is a potent neuromodulator in the brain that affects a wide range of motivated behaviors. Abnormal concentration of DA is related to a variety of diseases. Hence, it is imperative to establish a rapid and precise method for quantifying DA. In this work, we integrate orange-yellow emissive carbon dots (CDs) with target-induced silver deposition on gold nanoparticles (Au NPs), forming gold/silver core-shell nanoparticles (Au@Ag NPs), to construct a fluorometric and colorimetric dual-signal sensor for sensitive detection of DA. Au NPs and silver ions (Ag + ) have minimal effect on the fluorescence of CDs. DA can reduce the silver ions to Ag(0) on the surface of the Au NPs to form a silver shell, resulting in the blue-shift of the absorbance peak from 520 to 416 nm, which overlaps with the excitation spectrum of CDs. As a result, the system color turns from pink to orange-yellow, and the fluorescence of CDs is quenched due to the strong inner filter effect. The linear range of the colorimetry is 0.5-18 μM with a limit of detection (LOD) of 0.41 μM, while the linear range for the fluorometry method is 0.5-14 μM with a LOD of 0.021 μM. This method demonstrates notable advantages including a low detection limit, rapid response time, and straightforward operation in practical samples, showing great potential in biomedical analysis., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

In the current study, silver nanoparticles (AgNPs) incorporated Polyamide 66 (PA66) nanofiber mat as a photocatalyst which was prepared using electrospinning technique for degradation of methyl orange (MO). Considering the lack of reported studies on the influence of the ultrasonication on the size and stability of AgNPs, the purpose of the study was to produce a small size of AgNPs and compare it with the continuous stirring method. It is reasonable to report that the advantage of ultrasonication is to generate relatively smaller AgNPs (u-AgNPs) compared to fabrication by continuous stirring method (s-AgNPs). Helichrysum arenarium (HA) extract was used as a reducing agent as well as a capping agent in green synthesis of AgNPs. AgNPs were characterized by UV-visible spectrophotometry, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and transmission electron microscope (TEM). PA66/u-AgNs nanofibers were then successfully electrospun and characterized by using scanning electron microscope (SEM), FT-IR, thermal gravimetric analysis (TGA), and water contact angle measurement (WCA). Fabricated PA66-based nanofiber mat with smooth surface and uniform diameters (330-340 nm) was used as a catalyst in MO degradation. PA66/u-AgNP nanofibers were also evaluated for antibacterial performance and showed significant inhibition against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa bacteria. According to these findings, it is expected that the fabricated novel PA66/u-AgNP nanofibers can be announced as a promising potent and applied to the wastewater applications., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Gold nanoclusters (AuNCs) are a class of novel luminescent nanomaterials that exhibit unique properties of ultra-small size, featuring strong anti-photo-bleaching ability, substantial Stokes shift, good biocompatibility, and low toxicity. Various biomolecules have been developed as templates or ligands to protect AuNCs with enhanced stability and luminescent properties for biomedical applications. In this review, the synthesis of AuNCs based on biomolecules including amino acids, peptides, proteins and DNA are summarized. Owing to the advantages of biomolecule-protected AuNCs, they have been employed extensively for diverse applications. The biological applications, particularly in bioimaging, biosensing, disease therapy and biocatalysis have been described in detail herein. Finally, current challenges and future potential prospects of bio-templated AuNCs in biological research are briefly discussed., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Systems biology is increasingly being applied in nanosafety research for observing and predicting the biological perturbations inflicted by exposure to nanoparticles (NPs). In the present study, we used a combined transcriptomics and proteomics approach to assess the responses of human monocytic cells to Au-NPs of two different sizes with three different surface functional groups, i.e., alkyl ammonium bromide, alkyl sodium carboxylate, or poly(ethylene glycol) (PEG)-terminated Au-NPs. Cytotoxicity screening using THP-1 cells revealed a pronounced cytotoxicity for the ammonium-terminated Au-NPs, while no cell death was seen after exposure to the carboxylated or PEG-modified Au-NPs. Moreover, Au-NR3+ NPs, but not the Au-COOH NPs, were found to trigger dose-dependent lethality in vivo in the model organism, Caenorhabditis elegans. RNA sequencing combined with mass spectrometry-based proteomics predicted that the ammonium-modified Au-NPs elicited mitochondrial dysfunction. The latter results were validated by using an array of assays to monitor mitochondrial function. Au-NR3+ NPs were localized in mitochondria of THP-1 cells. Moreover, the cationic Au-NPs triggered autophagy in macrophage-like RFP-GFP-LC3 reporter cells, and cell death was aggravated upon inhibition of autophagy. Taken together, these studies have disclosed mitochondria-dependent effects of cationic Au-NPs resulting in the rapid demise of the cells.

With the extensive use of silver nanoparticles (AgNPs) in various consumer products their potential toxicity is of great concern especially for highly sensitive population groups such as pregnant women and even the developing fetus. To understand if AgNPs are taken up and cross the human placenta, we studied their translocation and accumulation in the human ex vivo placenta perfusion model by single particle ICP-MS (spICP-MS). The impact of different surface modifications on placental transfer was assessed by AgNPs with two different modifications: polyethylene glycol (AgPEG NPs) and sodium carboxylate (AgCOONa NPs). AgNPs and ionic Ag were detected in the fetal circulation in low but not negligible amounts. Slightly higher Ag translocation across the placental barrier for perfusion with AgPEG NPs and higher AgNP accumulation in placental tissue for perfusion with AgCOONa NPs were observed. Since these AgNPs are soluble in water, we tried to distinguish between the translocation of dissolved and particulate Ag. Perfusion with AgNO3 revealed the formation of Ag containing NPs in both circulations over time, of which the amount and their size in the fetal circulation were comparable to those from perfusion experiments with both AgNP types. Although we were not able to clarify whether intact AgNPs and/or Ag precipitates from dissolved Ag cross the placental barrier, our study highlights that uptake of Ag ions and/or dissolution of AgNPs in the tissue followed by re-precipitation in the fetal circulation needs to be considered as an important pathway in studies of AgNP translocation across biological barriers.

Pharmaceutical, food packing, cosmetics, agriculture, energy storage devices widely utilize metal and metal oxide nanoparticles prepared via different physical and chemical methods. It resulted in the release of several dangerous compounds and solvents as the nanoparticles were being formed. Currently, Researchers interested in preparing nanoparticles (NPs) via biological approach due to their unique physiochemical properties which took part in reducing the environmental risks. However, a number of microbial species are causing dangerous illnesses and are a threat to the entire planet. The metal and metal oxide nanoparticles played a significant role in the identification and elimination of microbes when prepared using natural extract. Its biological performance is thus also becoming exponentially more apparent than it was using in conventional techniques. Despite the fact that they hurt germs, their small size and well-defined shape encourage surface contact with them. The generation of Reactive Oxygen Species (ROS), weakens the bacterial cell membrane by allowing internal cellular components to seep out. The bacterium dies as a result of this. Numerous studies on different nanoparticles and their antibacterial efficacy against various diseases are still accessible. The main objective of the biogenic research on the synthesis of key metals and metal oxides (such as gold, silver, titanium dioxide, nickel oxide, and zinc oxide) using various plant extracts is reviewed in this study along with the process of nanoparticle formation and the importance of phytochemicals found in the plant extract., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A highly sensitive colorimetric method (glycan-based nano(e)zyme) was developed for sensitive and rapid detection of the SARS-CoV-2 virus based on N-acetyl neuraminic acid (sialic acid)-functionalized gold nanoparticles (SA-Au NZs). A number of techniques were used to characterize the prepared nanomaterials including XRD, FT-IR, UV-vis, DLS, and TEM. DLS analysis indicates an average hydrodynamic size of 34 nm, whereas TEM analysis indicates an average particle size of 15.78 nm. This observation confirms that water interacts with nanoparticle surfaces, resulting in a large hydrodynamic diameter. The peroxidase-like activity of SA-Au NZs was examined with SARS-CoV-2 and influenza viruses (influenza A (H1N1), influenza A (H3N2), and influenza B). UV-visible spectroscopy was used to monitor and record the results, as well as naked eye detection (photographs). SA-Au NZs exhibit a change in color from light red to purple when SARS-CoV-2 is present, and they exhibit a redshift in their spectrum. N-acetyl neuraminic acid interacts with SARS-CoV-2 spike glycoprotein, confirming its ability to bind glycans. As a result, SA-Au NZs can detect COVID-19 with sensitivity and specificity of over 95% and 98%, respectively. This method was approved by testing saliva samples from 533 suspected individuals at Ghaem Hospital of Mashhad, Mashhad, Iran. Sensitivity and specificity were calculated by comparing the results with the definitive results. The positive results were accompanied by a color change from bright red to purple within five minutes. Statistical analysis was performed based on variables such as age, gender, smoking, diabetes, hypertension, and lung involvement. In clinical trials, it was demonstrated that this method can be used to diagnose SARS-CoV-2 in a variety of places, such as medical centers, hospitals, airports, universities, and schools., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Aim: Nanoparticle-based drug carriers hold great promise for the development of targeted therapies in pregnancy with reduced off-target effects. Here, we performed a mechanistic in vitro study on placental localization and penetration of gold nanoparticles (AuNPs) in dependence of particle size and surface modification., Materials & Methods: AuNP uptake and penetration in human placental coculture microtissues was assessed by inductively coupled plasma-mass spectrometry, transmission electron microscopy and laser ablation-inductively coupled plasma-mass spectrometry., Results: Higher uptake and deeper penetration was observed for smaller (3-4 nm) or sodium carboxylate-modified AuNPs than for larger (13-14 nm) or PEGylate AuNPs, which barely passed the trophoblast barrier layer., Conclusion: It is possible to steer placental uptake and penetration of AuNPs by tailoring their properties, which is a prerequisite for the development of targeted therapies in pregnancy.

Thorough characterization of toxic effects of nanoparticles (NP) is desirable due to the increasing risk of potential environmental contamination by NP. In the current study, we combined three recently developed proteomics approaches to assess the effects of Au, CuO, and CdTe NP on the innate immune system. The human monocyte cell line THP-1 was employed as a model. The anticancer drugs camptothecin and doxorubicin were used as positive controls for cell death, and lipopolysaccharide was chosen as a positive control for proinflammatory activation. Despite equivalent overall toxicity effect (50 ± 10% dead cells), the three NP induced distinctly different proteomics signatures, with the strongest effect being induced by CdTe NP, followed by CuO and gold NP. The CdTe toxicity mechanism involves down-regulation of topoisomerases. The effect of CuO NP is most reminiscent of oxidative stress and involves up-regulation of proteins involved in heat response. The gold NP induced up-regulation of the inflammatory mediator, NF-κB, and its inhibitor TIPE2 was identified as a direct target of gold NP. Furthermore, gold NP triggered activation of NF-κB as evidenced by phosphorylation of the p65 subunit. Overall, the combined proteomics approach described here can be used to characterize the effects of NP on immune cells.

Fabrication and development of nanoscale materials with tunable structural and functional properties require a dynamic arrangement of nanoparticles on architectural templates. The function of nanoparticles not only depends on the property of the nanoparticles but also on their spatial orientations. Proteins with self-assembling properties which can be genetically engineered to varying architectural designs for scaffolds can be used to develop different orientations of nanoparticles in three dimensions. Here, we report the use of naturally self-assembling bacterial micro-compartment shell protein (PduA) assemblies in 2D and its single-point mutant variant (PduA[K26A]) in 3D architectures for the reduction and fabrication of gold nanoparticles. Interestingly, the different spatial organization of gold nanoparticles resulted in a smaller size in the 3D architect scaffold. Here, we observed a two-fold increase in catalytic activity and six-fold higher affinity toward TMB (3,3',5,5'-tetramethylbenzidine) substrate as a measure of higher peroxidase activity (nanozymatic) in the case of PduA[K26A] 3D scaffold. This approach demonstrates that the hierarchical organization of scaffold enables the fine-tuning of nanoparticle properties, thus paving the way toward the design of new nanoscale materials., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Single-molecule detection represents the ultimate sensitivity in measurement science with the characteristics of simplicity, rapidity, low sample consumption, and high signal-to-noise ratio and has attracted considerable attentions in biosensor development. In recent years, a variety of functional nanomaterials with unique chemical, optical, mechanical, and electronic features have been synthesized. The integration of single-molecule detection with functional nanomaterials enables the construction of novel single-molecule fluorescent nanosensors with excellent performance. Herein, we review the advance in single-molecule fluorescent nanosensors constructed by novel nanomaterials including quantum dots, gold nanoparticles, upconversion nanoparticles, fluorescent conjugated polymer nanoparticles, nanosheets, and magnetic nanoparticles in the past decade (2011-2020), and discuss the strategies, features, and applications of single-molecule fluorescent nanosensors in the detection of microRNAs, DNAs, enzymes, proteins, viruses, and live cells. Moreover, we highlight the future direction and challenges in this area. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > In Vitro Nanoparticle-Based Sensing Diagnostic Tools > Diagnostic Nanodevices., (© 2021 Wiley Periodicals LLC.)

The design of redox-robust polymers is called for in view of interactions with nanoparticles and surfaces toward applications in nanonetwork design, sensing, and catalysis. Redox-robust triazolylbiferrocenyl (trzBiFc) polymers have been synthesized with the organometallic group in the side chain by ring-opening metathesis polymerization using Grubbs-III catalyst or radical polymerization and with the organometallic group in the main chain by Cu(I) azide alkyne cycloaddition (CuAAC) catalyzed by [Cu(I)(hexabenzyltren)]Br. Oxidation of the trzBiFc polymers with ferricenium hexafluorophosphate yields the stable 35-electron class-II mixed-valent biferrocenium polymer. Oxidation of these polymers with Au(III) or Ag(I) gives nanosnake-shaped networks (observed by transmission electron microscopy and atomic force microscopy) of this mixed-valent Fe(II)Fe(III) polymer with encapsulated metal nanoparticles (NPs) when the organoiron group is located on the side chain. The factors that are suggested to be synergistically responsible for the NP stabilization and network formation are the polymer bulk, the trz coordination, the nearby cationic charge of trzBiFc, and the inter-BiFc distance. For instance, reduction of such an oxidized trzBiFc-AuNP polymer to the neutral trzBiFc-AuNP polymer with NaBH4 destroys the network, and the product flocculates. The polymers easily provide modified electrodes that sense, via the oxidized Fe(II)Fe(III) and Fe(III)Fe(III) polymer states, respectively, ATP(2-) via the outer ferrocenyl units of the polymer and Pd(II) via the inner Fc units; this recognition works well in dichloromethane, but also to a lesser extent in water with NaCl as the electrolyte.

Microbial synthesis of gold nanoparticles (AuNPs), which are used in various forms with different properties in medicine, as a renewable bioresource has become increasingly important in recent years. In this study, statistical optimization of stable and monodispersed AuNPs synthesis was performed using a cell-free fermentation broth of Streptomyces sp. M137-2 and AuNPs were characterized, and their cytotoxicity was determined. The three factors determined as pH, gold salt (HAuCl 4 ) concentration, and incubation time, which are effective in the extracellular synthesis of biogenic AuNPs, were optimized by Central Composite Design (CCD) and then UV-Vis Spectroscopy, Dynamic Light Scattering (DLS), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Scanning Transmission Electron Microscope (STEM), size distribution, Fourier-Transform Infrared (FT-IR) Spectroscopy, X-Ray Photoelectron Spectrophotometer (XPS) and stability analyzes of AuNPs were carried out. Optimum values of the factors were determined as pH 8, 10 - 3  M HAuCl 4 , and 72 h incubation using Response Surface Methodology (RSM). Almost spherical AuNPs with 20-25 nm protein corona on the surface, 40-50 nm in size, monodisperse, and highly stable form were synthesized. Biogenic AuNPs were confirmed from characteristic diffraction peaks in the XRD pattern, UV-vis peak centred at 541 nm. The FT-IR results confirmed the role of Streptomyces sp. M137-2 metabolites in the reduction and stabilization of AuNPs. The cytotoxicity results also showed that AuNPs obtained using Streptomyces sp. can be used safely in medicine. This is the first report to perform statistical optimization of size-dependent biogenic AuNPs synthesis using a microorganism., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Long-term stable 3 nm gold nanoparticles are prepared by a simple reaction between HAuCl4 and sodium borohydride in water under ambient conditions which very efficiently catalyze 4-nitrophenol reduction to 4-nitroaniline.

Monofunctional triazoles linked to ferrocene, ferricenium, or coumarin (Cou), easily synthesized by copper-catalyzed azide alkyne (CuAAC) "click" reactions between the corresponding functional azides and (trimethylsilyl)acetylene followed by silyl group deprotection, provide a variety of convenient neutral ligands for the stabilization of functional gold nanoparticles (AuNPs) in polar organic solvents. These triazole (trz)-AuNPs are very useful toward a variety of applications to synthesis, sensing, and catalysis. Both ferrocenyl (Fc) and isostructural ferricenium linked triazoles give rise to AuNP stabilization, although by different synthetic routes. Indeed, the first direct synthesis and stabilization of AuNPs by ferricenium are obtained by the reduction of HAuCl4 upon reaction with a ferrocene derivative, AuNP stabilization resulting from a synergy between electrostatic and coordination effects. The ferricenium/ferrocene trz-AuNP redox couple is fully reversible, as shown by cyclic voltammograms that were recorded with both redox forms. These trz-AuNPs are stable for weeks in various polar solvents, but at the same time, the advantage of trz-AuNPs is the easy substitution of neutral trz ligands by thiols and other ligands, giving rise to applications. Indeed, this ligand substitution of trz at the AuNP surface yields a stable Fc-terminated nanogold-cored dendrimer upon reaction with a Fc-terminated thiol dendron, substitution of Cou-linked trz with cysteine, homocysteine, and glutathione provides remarkably efficient biothiol sensing, and a ferricenium-linked trz-AuNP catalyst is effective for NaBH4 reduction of 4-nitrophenol to 4-aminophenol. In this catalytic example, the additional electrostatic AuNP stabilization modulates the reaction rate and induction time.

Catalysis by palladium derivatives is now one of the most important tools in organic synthesis. Whether researchers design palladium nanoparticles (NPs) or nanoparticles occur as palladium complexes decompose, these structures can serve as central precatalysts in common carbon-carbon bond formation. Palladium NPs are also valuable alternatives to molecular catalysts because they do not require costly and toxic ligands. In this Account, we review the role of "homeopathic" palladium catalysts in carbon-carbon coupling reactions. Seminal studies from the groups of Beletskaya, Reetz, and de Vries showed that palladium NPs can catalyze Heck and Suzuki-Miyaura reactions with aryl iodides and, in some cases, aryl bromides at part per million levels. As a result, researchers coined the term "homeopathic" palladium catalysis. Industry has developed large-scale applications of these transformations. In addition, chemists have used Crooks' concept of dendrimer encapsulation to set up efficient nanofilters for Suzuki-Miyaura and selective Heck catalysis, although these transformations required high PdNP loading. With arene-centered, ferrocenyl-terminated dendrimers containing triazolyl ligands in the tethers, we designed several generations of dendrimers to compare their catalytic efficiencies, varied the numbers of Pd atoms in the PdNPs, and examined encapsulation vs stabilization. The catalytic efficiencies achieved "homeopathic" (TON = 540 000) behavior no matter the PdNP size and stabilization type. The TON increased with decreasing the Pd/substrate ratio, which suggested a leaching mechanism. Recently, we showed that water-soluble arene-centered dendrimers with tri(ethylene glycol) (TEG) tethers stabilized PdNPs involving supramolecular dendritic assemblies because of the interpenetration of the TEG branches. Such PdNPs are stable and retain their "homeopathic" catalytic activities for Suzuki-Miyaura reactions for months. (TONs can reach 2.7 × 10(6) at 80 °C for aryl bromides and similar values for aryl iodides at 28 °C.) Sonogashira reactions catalyzed by these PdNPs are quantitative with only 0.01% Pd/mol substrate. Kato's group has reported remarkable catalytic efficiencies for mesoporous catalysts formed by polyamidoamine (PAMAM) dendrimer polymerizations. These and other mesoporous structures could allow for catalyst recycling, with efficiencies approaching the "homeopathic" behavior. In recent examples of Suzuki-Miyaura reactions of aryl chlorides, chemists achieved truly "homeopathic" catalysis when a surfactant such as a tetra-n-butylammonium halide or an imidazolium salt was used in stoichiometric quantities with substrate. These results suggest that the reactive halide anion of the salt attacks the neutral Pd species to form a palladate. In the case of aryl chlorides, the reaction may occur through the difficult, rate-limiting oxidative-addition step.

In the present research work, a highly recyclable catalyst of Ag-based agarose (HRC-Ag/Agar) hydrogel was successfully fabricated through a simple and efficient in situ reduction method without the aid of additional surface active agent. The interaction between the rich hydroxyl functional (-OH) groups in agarose and Ag can effectively control the growth and dispersion of Ag nanoparticles (NPs) in the HRC-Ag/Agar hydrogel and keep Ag NPs free from chemical contamination, which also guarantees the reusability of HRC-Ag/Agar hydrogel as catalysts. HRC-Ag/Agar hydrogel without freeze drying and calcination was investigated for their potential applications as highly active/recyclable catalysts in reducing aromatic organic pollutants (p-nitrophenol (4-NP), methylene blue (MB) and rhodamine B (RhB)) by KBH 4 . The optimal HRC-Ag/Agar-1.9 hydrogel can complete the catalytic reduction of 4-NP within 11 min. Moreover, HRC-Ag/Agar-1.9 hydrogel achieves the high conversion rate (> 99%) through ten catalytic runs. Similarly, HRC-Ag/Agar-1.9 hydrogel was able to achieve a reduction efficiency of RhB at 98% within 17 min and that of MB at 95% within 40 min. The advantages of simple synthetic procedure, no secondary pollution, strong stability and easily separated make the HRC-Ag/Agar hydrogel have great potential prospect for environmental applications., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The aim of these studies was to synthesize, characterize and evaluate the efficacy of pegylated gold nanoparticles (AuNPs) that differed in their PEG molecular weight, using PEG 550 and PEG 2000. The synthesis of the gold nanoparticles was carried out by modified Brust method with a diameter of 4-15 nm. The targeting agent folic acid was introduced by the covalent linkage. Finally, the anti-cancer drug docetaxel was encapsulated by the AuNPs by non covalent adsorption. The nanoparticles were characterized by transmission electron microscopy and used for in vitro studies against a hormone-responsive prostate cancer cell line, LnCaP. The loaded nanoparticles reduced the cell viability in more than 50% at concentrations of 6 nM and above after 144 h of treatment. Moreover, observation of prostate cancer cells by optical microscopy showed damage to the cells after exposure to drug-loaded AuNPs while unloaded AuNPs had much less effect., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Palladium nanoparticles (PdNPs) with a size of 1.4 nm are stabilized by dendritic nanoreactors containing 1,2,3-triazole ligands with hydrophilic triethylene glycol (TEG) termini. These PdNPs are stable for months under air and are extremely active for the Suzuki-Miyaura reactions of aryl bromides down to sub-ppm levels.

"Click" chemistry now offers access to a great variety of triazoles, and the first example of a strategy to stabilize gold nanoparticles (AuNPs) with a new 1,2,3-triazole-mPEG ligand is developed here together with preliminary examples of possible applications.

This critical review focuses on the anti-cancer fight using gold nanoparticles (AuNPs) functionalized with chemotherapeutic drugs in so-called "complexes" (supramolecular assemblies) and "conjugates" (covalent assemblies) as vectors. There is a considerable body of recent literature on various tumor-imaging techniques using the surface plasmon band (SPB) and the "passive" and "active" vectorization of anti-cancer drugs. This article reviews the main concepts and the most recent literature data with emphasis on AuNP preparation, cytotoxicities and use in selective targeting of cancer cells with over-expressed receptors for diagnosis and therapy (108 references)., (This journal is © The Royal Society of Chemistry 2012)

Encapsulation of docetaxel and its solubilization in water was carried out in PEGylated gold nanoparticles (AuNPs) as shown by 1H NMR (600 MHz) and UV/Vis spectroscopy and dynamic light scattering. Vectorization of PEGylated AuNP-encapsulated docetaxel was probed in vitro toward human colon carcinoma (HCT15) and human breast cancer (MCF7) cells. AuNPs alone presented no cytotoxicity toward either MCF7 or HCT15 adenocarcinoma cells. AuNP-docetaxel was found to be 2.5-fold more efficient than docetaxel alone against MCF7 cells, and the IC50 value of AuNP-docetaxel against HCT15 cells was lower than that of free docetaxel; the increased efficiency brought about by AuNP drug encapsulation was ∼1.5-fold., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Functionalized colloidal gold is widely used for qualitative and quantitative detection of specific analytes. We report here a novel modification of gold nanoparticles by digitonin, a glycoside used for precipitating membrane cholesterol. The specific molecular recognition of cholesterol by digitonin gold nanoparticles (DGNP), make it an attractive alternative to the existing enzymatic methods for cholesterol sensing. To enable cholesterol binding, we modified mercapto modified GNPs with digitonin, by a simple esterification reaction. The blue shift in the plasmon absorption spectra of DGNP with different cholesterol concentrations accompanied by a decrease in the absorbance is the principle applied here for the estimation. The observed size reduction followed by cholesterol binding is reasoned due to the enhanced hydophobicity of the surface which in turn expels the water layers associated with the particles prior to cholesterol binding. The method exhibited linearity between concentration of cholesterol and the corresponding absorbance of the plasmon peak, in the range of 160-600 ng/mL with a detection limit of 100±9 ng/mL. Other steroids did not show any binding affinity towards DGNP. The method depicted here has potential for development as an enzyme free sensor for cholesterol although many factors need to be addressed to transform it for assaying samples like blood., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Fe 3 O 4 /Au/porous Au nanohybrids being bi-functional nanoparticles with magnetic properties and high porosity, were synthesized and used for drug delivery. To achieve this purpose, after Fe 3 O 4 nanoparticles synthesis, a gold layer coats them to increase their stability. Then, to improve the loading capacity of Fe 3 O 4 /Au nanoparticles, a shell of porous gold was synthesized on the Fe 3 O 4 /Au surface by creating an Ag-Au nanohybrid layer on Fe 3 O 4 /Au and dissolving the metallic silver atoms in HNO 3 (0.01 M). The DLS results show that the synthesized nanohybrid has an average size of 68.0 ± 7.7 nm and a zeta potential of - 28.1 ± 0.2 mV. Finally, doxorubicin (DOX), as a pharmaceutical agent, was loaded onto the Fe 3 O 4 /Au/porous Au nanohybrids. The prepared nano-drug enhanced the therapeutic efficacy of DOX on MCF-7 cancer cells compared to the free DOX. These results confirmed a 1.5 times improvement in the antitumor activity of DOX-loaded Fe 3 O 4 /Au/porous Au nanohybrids., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Recently, nanozymes based on polymer-stabilized gold nanoparticles (AuNPs) have attracted more and more attention on account of their polymer-ligands' multiple functionalization sites. However, the contribution of polymer hydrogen bonding to the catalytic activity of AuNPs has received little attention. This study designed and fabricated poly(N-2-hydroxypropylmethacrylamide)-capped AuNPs (PHPAM@AuNPs) using a hydroxyl-rich polymer as the ligand. The PHPAM@AuNPs exhibited good peroxidase-mimicking activity capable of efficiently oxidizing 3,3'5,5'-tetramethylbenzidine (TMB) with H 2 O 2 . The effect of PHPAM hydrogen bonding on the catalytic activity of PHPAM@AuNPs was investigated. Under peroxidase-mimicking catalysis, homocysteine introduced a notable reduction in oxidation, allowing the creation of a colorimetric method for homocysteine detection with high selectivity and sensitivity. The ultraviolet-visible absorption intensity of oxidized TMB showed a strong linear relationship with homocysteine concentration in the range of 3.0-20.0 μM (R 2  = 0.998), with a limit of detection of 0.4 μM. The proposed colorimetric protocol was used to monitor homocysteine in rat serum following intraperitoneal injection. This work provides a new way to refine AuNP-based nanozymes by relying on polymer-ligand hydrogen bonding. It has strong application potential in the analysis of endogenous molecules in real samples., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)

Sensitive determination of ofloxacin (OFL) is very essential for human health and environmental protection. Here, a novel composite of gold nanoparticles(nAu)@MXene(Ti 3 C 2 T x )/poly-p-aminobenzene sulfonic acid (PABSA) was fabricated on the surface of glassy carbon electrode (GCE) and used to sensitively determine OFL. The results of experiments showed that the obtained nAu@Ti 3 C 2 T x /PABSA/GCE electrode could be used as an electrochemical sensor to directly detect ofloxacin (OFL) by differential pulse voltammetry (DPV). Under the optimal conditions, the proposed electrode displayed a broader linear range and a lower detection limit (LOD) for OFL determination when it was compared to those similar sensors. The linear range was from 5.0 × 10 -8 to 5.0 × 10 -4  mol/L and the LOD was 3.7 × 10 -8  mol/L (S/N = 3). The nAu@Ti 3 C 2 T x /PABSA/GCE electrode also showed good selectivity, repeatability, and reproducibility. Finally, the proposed electrode was used to detect OFL in commercial samples by the standard addition method. The obtained recovery was from 97.3% and 105.7% showing its potential applications in actual sample analysis., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)

Advances in nanotechnology and medical science have spurred the development of engineered nanomaterials and nanoparticles with particular focus on their applications in biomedicine. In particular, gold nanoparticles (AuNPs) have been the focus of great interest, due to their exquisite intrinsic properties, such as ease of synthesis and surface functionalization, tunable size and shape, lack of acute toxicity and favorable optical, electronic, and physicochemical features, which possess great value for application in biodetection and diagnostics purposes, including molecular sensing, photoimaging, and application under the form of portable and simple biosensors (e.g., lateral flow immunoassays that have been extensively exploited during the current COVID-19 pandemic). We shall discuss the main properties of AuNPs, their synthesis and conjugation to biorecognition moieties, and the current trends in sensing and detection in biomedicine and diagnostics. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > In Vitro Nanoparticle-Based Sensing Diagnostic Tools > In Vivo Nanodiagnostics and Imaging., (© 2022 Wiley Periodicals LLC.)

Nanotechnology is an emerging and expanding technology worldwide. The manipulation of materials on a nanometric scale generates new products with unique properties called nanomaterials. Due to its significant expansion, nanotechnology has been applied in several fields of study, including developing materials for biomedical applications, i.e., nanomedicine. The use of nanomaterials, including nanoparticles, in nanomedicine, is promising and has been associated with pharmacokinetics, bioavailability, and therapeutic advantages. In this regard, it is worth mentioning the Gold Nanoparticles (AuNPs). AuNPs' biomedical application is extensively investigated due to their high biocompatibility, simple preparation, catalytic, and redox properties. Experimental studies have pointed out critical therapeutic actions related to AuNPs in different pathophysiological contexts, mainly due to their anti-inflammatory and antioxidant effects. Thus, in this review, we will discuss the main experimental findings related to the therapeutic properties of AuNPs in metabolic, neurodegenerative diseases, and ultimately brain dysfunctions related to metabolic diseases., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer with enhanced metastasis and poor survival. Though chemotherapy, radiotherapy, photothermal therapy (PTT), photodynamic therapy (PDT), and gene delivery are used to treat TNBC, various side effects limit these therapeutics against TNBC. In this review article, we have focused on the mechanism of action of gold nanoparticles (AuNPs) to enhance the efficacy of therapeutics with targeted delivery on TNBC cells., Methods: Research data were accumulated from PubMed, Scopus, Web of Science, and Google Scholar using searching criteria "gold nanoparticles and triple-negative breast cancer" and "gold nanoparticles and cancer". Though we reviewed many old papers, the most cited papers were from the last ten years., Results: Various studies indicate that AuNPs can enhance bioavailability, site-specific drug delivery, and efficacy of chemotherapy, radiotherapy, PTT, and PDT as well as modulate gene expression. The role of AuNPs in the modulation of TNBC therapeutics through the inhibition of cell proliferation, progression, and metastasis has been proved in vitro and in vivo studies. As these mechanistic actions of AuNPs are most desirable to develop drugs with enhanced therapeutic efficacy against TNBC, it might be a promising approach to apply AuNPs for TNBC therapeutics., Conclusion: This article reviewed the mechanism of action of AuNPs and their application in the enhancement of therapeutics against TNBC. Much more attention is required for studying the role of AuNPs in developing them either as a single or synergistic anticancer agent against TNBC., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Due to being low cost and eco-friendly, biological nanomaterial synthesis and development have made broad spectral progress. This study aimed to optimize the phytomediated synthesis of catalytically active, antibacterial palladium nanoparticles (PdNPs) for adsorption-based removal of ethidium bromide (EtBr) from an aqueous solution. Optimization of synthesis demonstrated that a precursor to extract ratio of 4:1, pH 3, and incubation at 80 °C for 60 min were the optimum conditions that led to the synthesis of negatively charged, highly stable, polycrystalline, spherical, and monodispersed PdNPs of 5-10 nm. When tested as catalysts, PdNPs successfully catalyzed Suzuki-Miyaura cross-coupling between aryl halides and arylboronic acids resulting in the synthesis of 4-acetylbiphenyl. Furthermore, the antibacterial activity test demonstrated that biogenic PdNPs were most effective and potent against Staphylococcus aureus and Proteus vulgaris followed by Escherichia coli, Bacillus subtilis, and Bacillus cereus. In addition, PdNPs were found as an excellent adsorbent for adsorption of EtBr from water as the adsorption reaction obeyed pseudo-second-order kinetics with a linear regression coefficient (R 2  > 0.995). The adsorption reaction fitted well with the Freundlich and Temkin isotherm models, indicating multi-layer adsorption. Estimating thermodynamic parameters resulted in a positive value of ΔH 0 and ΔG 0 , demonstrating adsorption was non-spontaneous and endothermic., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Metal nanoparticles (NPs) exhibit several unique physicochemical properties, including redox activity, surface plasmon resonance, ability to quench fluorescence, biocompatibility, or a high surface-to-volume ratio. They are being increasingly used in analysis and preconcentration of thiol containing compounds, because they are able to spontaneously form a stable Au/Ag/Cu-S dative bond. They thus find wide application in environmental and particularly in medical science, especially in the analysis of biological thiols, the endogenous compounds that play a significant role in many biological systems. In this review article, we provide an overview of various types of NPs that have been applied in analysis and preconcentration of biological thiols, mainly in human biological fluids. We first discuss shortly the types of NPs and their synthesis, properties, and their ability to interact with thiol compounds. Then we outline the sample preconcentration and analysis methods that were used for this purpose with special emphasis on optical, electrochemical, and separation techniques., (© 2022 Wiley-VCH GmbH.)

The presence of humic acid compounds in water resources, as one of the precursors of Trihalomethanes and Holoacetic acids, causes health problems for many communities. The aim of this research study was to investigate the photocatalytic degradation efficiency of humic acid using MnFe 2 O 4 @TiO 2 nanoparticles which produced by green synthesis method. The synthesis of metal nanoparticles using plant extracts and the study of their catalytic performance is a relatively new topic. Many chemical techniques have been proposed for the synthesis of MnFe 2 O 4 @TiO 2 nanoparticles, but green synthesis has received much attention due to its availability, simplicity, and non-toxicity. The properties of synthesized nanoparticles were determined by SEM, FT-IR, XRD, EDS, and DLS analysis. The results of the study showed that under optimal experimental conditions (pH = 3, nanocomposite dose = 0.03 g/L, humic acid initial concentration = 2 mg/L, and contact time = 20 min), it is possible to achieve maximum degradation of humic acid. Therefore; MnFe 2 O 4 @TiO 2 nanoparticles have high efficiency for removing of humic acid from aqueous solutions under UV light., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This critical review provides an overall survey of the basic concepts and up-to-date literature results concerning the very promising use of gold nanoparticles (AuNPs) for medicinal applications. It includes AuNP synthesis, assembly and conjugation with biological and biocompatible ligands, plasmon-based labeling and imaging, optical and electrochemical sensing, diagnostics, therapy (drug vectorization and DNA/gene delivery) for various diseases, in particular cancer (also Alzheimer, HIV, hepatitis, tuberculosis, arthritis, diabetes) and the essential in vitro and in vivo toxicity. It will interest the medicine, chemistry, spectroscopy, biochemistry, biophysics and nanoscience communities (211 references).

Difficulties previously encountered in the very useful "click" functionalization of gold nanoparticles (AuNPs) resulting in low yields are now overcome by using specific conditions: 1:1 water-THF medium, stoichiometric CuSO(4) and sodium ascorbate, inert atmosphere at 20 degrees C that provide quantitative "click" reactions between azidoalkylthiolate-AuNPs with various hydrophilic (PEG-containing) and hydrophobic (organic and organometallic) alkynes.

Gold nanoparticles (AuNPs) are synthesized and stabilized by new "clicked" dendrimers of generations zero to two (G(0)-G(2)) containing tri- and tetra-ethyleneglycol tethers; they are either encapsulated by G(1) (81 tethers) and G(2) (243 tethers) or stabilized without encapsulation by G(0) (27 tethers).

"Click" dendrimers containing 1,2,3-triazolyl ligands that coordinate to PdII(OAc)2 have been synthesized in view of catalytic applications. Five of these dendrimers contain ferrocenyl termini directly attached to the triazole ligand in order to monitor the number of PdII that are introduced into the dendrimers by cyclic voltammetry. Reduction of the PdII-triazole dendrimers by using NaBH4 or methanol yields Pd nanoparticles (PdNPs) that are stabilized either by several dendrimers (G0, DSN) or by encapsulation inside a dendrimer (G1 and G2: DEN), as confirmed by TEM. Relative to PAMAM-DENs (PAMAM=poly(amidoamine)), the "click" DSNs and DENs show a remarkable efficiency and stability for olefin hydrogenation under ambient conditions of various substrates. The influence of the reductant of PdII bound to the dendrimers is dramatic, reduction with methanol leading to much higher catalytic activity than reduction with NaBH4. The most active NPs are shown to be those derived from dendrimer G1, and variation of its termini groups (ferrocenyl, alkyl, phenyl) allowed us to clearly delineate, optimize, and rationalize the role of the dendrimer frameworks on the catalytic efficiencies. Finally, hydrogenation of various substrates catalyzed by these PdNPs shows remarkable selectivity features.

Covalent assembly between gold-thiolate nanoparticles (AuNPs) and the cluster [Fe(eta(5)-C(5)H(5))(mu(3)-CO)](4), 1, can be achieved either by direct Brust-Schriffin-type synthesis using a mixture of undecanethiol and a thiol functionalized with , or by substitution of undecanethiolate ligands in AuNPs by thiolate ligands functionalized with ; cyclic voltammetry of these AuNPs functionalized with allows us to recognize and titrate the oxo-anions H(2)PO(4)(-) and ATP(2-).

Wild-type microorganisms have become tolerant to higher antibiotic and antimicrobial agent concentrations due to the global increase in antibiotic consumption. Green-synthesized nanoparticles (NPs) have been proposed as potential antimicrobial agents to overcome the problem. This research prepared cadmium nanoparticles (Cd NPs) using Artemisia persica extract. To clarify the biological behavior of Cd NPs and Cd (NO 3 ) 2 , cytotoxicity, antibacterial, anti-biofilm, and biocompatible experiments were performed. Since Cd toxicity is associated with liver, kidney damage, and other deficits, HepG2 and HUVEC cell lines were employed as the in vitro cytotoxicity models. Cd NPs had a lower cytotoxic effect than Cd (NO 3 ) 2 against both HepG2 and HUVEC cells. The Cd NPs exhibited no hemolysis activity. The antibacterial and anti-biofilm studies were conducted using gram-positive Staphylococcus aureus and gram-negative Proteus mirabilis and Pseudomonas aeruginosa with the ability to form severe adherent biofilms. The antibacterial activity of Cd NPs against clinically isolated S. aureus, P. mirabilis, and P. aeruginosa was above 2560 µg mL - 1 . The Cd NPs (640 µg mL - 1 ) decreased the biofilm formation of S. aureus, P. mirabilis, and P. aeruginosa by 24.6%, 31.6%, and 26.4%, respectively.Moreover, adding Cd NPs (100 µg/disc) to antibiotic discs increased the antibacterial activity of vancomycin, gentamicin, tetracycline, streptomycin, meropenem, and kanamycin against Methicillin-resistant S. aureus, significantly. Due to the emergence of resistant microorganisms, Cd NPs can be used as an exciting material to counterattack global health problems. Further research is needed to clarify the molecular mechanisms underlying Cd NPs' pharmacological and toxicological effects., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Long-term and continuous monitoring of the microRNA (miRNA) expression in living cells is essential in biomedical research, but it is currently limited by fast consumption and easy digestion of probes in the intracellular environment. Herein, we report polydopamine-modified gold nanoparticles (AuNPs@PDA) as protective and efficient nanocarriers for DNA hairpin probes (hpDNA), achieving long-term monitoring (48 h) of the miRNA (let-7a) levels in living cells after drug treatments. This method enabled excellent sensitivity and high selectivity toward let-7a with a limit of detection of 0.51 nM (n = 3) and a linear range from 1 to 100 nM. More importantly, AuNPs@PDA can not only efficiently improve the loading of hpDNA on each nanoparticle, but also effectively protect hpDNA from hydrolysis in the cell microenvironment, finally realizing the continuous monitoring of let-7a in living cells for 48 h. This simple method would be of great significance for drug screening and precision medicine., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)

Nanoparticles plays a key role in the development of novel antibacterial substances against various pathogenic microorganisms. These nanoparticles due to their smaller size could be very effective as they can improve the antibacterial activity through lysis of bacterial cell wall. In the present research work, ZnO, MgO, NiO, AlO nanoparticles, and MgNiO, and AlZnO composite oxides were synthesized by green method from Ocimum basilicum leaves extract. The nanoparticles formed were evaluated using FTIR, XRD, EDX, and SEM to confirm the formation of NPs and to determine the morphology, elemental composition, shape and size, composition, and nature of bonds present in the NPs. Further, the NPs were tested for their antibacterial activity. In particular, ZnO NPs showed a good inhibitory effect against Pseudomonas aeruginosa with 20 mm zone of inhibition. Hence, the process reported herein could be optimized for large-scale preparation of NPs. RESEARCH HIGHLIGHTS: Green synthesis of ZnO, MgO, NiO, AlO nanoparticles, and MgNiO, and AlZnO composite oxides using Ocimum basilicum leaves extract NPs were characterized by various established characterization techniques like FTIR, XRD, EDX, and SEM. NPs showed antibacterial activity which was investigated by agar well diffusion method against Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. The method proved to be very simple, cost-efficient, and convenient., (© 2022 Wiley Periodicals LLC.)

In this research, a novel synthesis of CaO nanoparticles via a green, environmentally, and economical method is developed. Crataegus pontica C.Koch leaves extract was used as a green reducing and stabilizing agent to synthesize the calcium oxide nanoplates ranging from 40 to 65 nm. The synthesized CaO NPs are characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) spectroscopy. The CaO NPs were evaluated successfully for photocatalytic degradation of methylene blue (MB) dye with 98.99% degradation efficiency under sunlight by a simple technique. The recoverability and reusability of the CaO photocatalyst were considered under the optimized reaction conditions, which are showed high chemical stability after at least five runs., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In this experimental study, we aimed to evaluate the antibacterial and anti-biofilm effects of photodynamic therapy with a photosensitizer in conjunction with Gold nanoparticles against Streptococcus mutans as an important cariogenic bacterial agent. This experimental in vitro study evaluated the antibacterial and anti-biofilm effect of five groups as followed against S. mutans: methylene blue (MB), Gold nanoparticles (AuNPs), methylene blue conjugated with Gold nanoparticles (MB-AuNPs), MB mediated photodynamic therapy (MB mediated PDT) and methylene blue conjugated with Gold nanoparticles mediated photodynamic therapy (MB-AuNPs mediated PDT). InGaAlP laser (Azor-2 K) with 25 mW total output, 660 nm wavelength and laser probe cross-section of 0.78 cm 2 was used for methylene blue activation. Total dose of 19.23 J/cm 2 for 10 min was irradiated to each group. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and colony forming unit (CFU) were determined. Bacterial biofilm formation inhibition was assessed by crystal violet staining (The microtiter plate biofilm assay). The viability of S. mutans cells was assessed by MTT assay. MB mediated PDT and MB-AuNP mediated PDT were the most effective method for S. mutans biofilm inhibition (P < 0.05). MB alone, MB-AuNP alone and MB mediated PDT and MB-AuNP mediated PDT had the same effect against the planktonic phase of S. mutans (P > 0.05). Also they had similar pattern for bacterial growth inhibition and bactericidal effect (P > 0.05). Gold nano particle mediated photodynamic therapy represented antibacterial and antibiofilm activity against S. mutans; but this modality was not more effective than routine PDT., (© 2021. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

Gold nanoparticles (GNPs) are well-documented for their size and surface chemistry-dependent electronic and optical properties that are extensively utilized to develop highly sensitive immunoassays. GNP-based immuno-polymerase chain reaction (immuno-PCR) is especially interesting due to the facile loading of biomolecules on the surface of GNP probes and has been utilized to develop analyte-specific assays. In this study, the role of size and surface chemistry of GNPs is explored in detail to develop a highly sensitive and reproducible immuno-PCR assay for specific detection of biotinylated analytes. Our results indicate that smaller-sized gold nanoparticles outperform the larger ones in terms of their sensitivity in immuno-PCR assay and show superior loading of proteins and oligonucleotides on the surface of nanoparticles. Furthermore, the role of different macromolecular stabilizers (such as polyethylene glycol (PEG), bovine serum albumin (BSA), and PEGylated BSA) was compared to optimize the loading of biomolecules and to improve the signal-to-noise ratio of GNP probes. mPEG-BSA-functionalized GNP probes of 15 nm were found to be highly sensitive at low concentrations of analytes and significantly (~ 30 fold) improve the limit of detection of analytes in comparison with ELISA assay., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)

In this paper, novel synergetic PtNP@Co 3 O 4 hollow nanopolyhedrals with peroxidase-like activities are designed and prepared, which can be used as electrochemical and colorimetric signal labels for the enzyme-free dual-channel homogeneous sensing of prostate-specific antigen. When prostate-specific antigens are present, the aptamer-modified PtNP@Co 3 O 4 hollow nanopolyhedrals and magnetic beads form sandwich structures, which have excellent peroxidase-like activities, because of the synergetic effect of PtNP@Co 3 O 4 hollow nanopolyhedrals. The sandwich structures can be separated from the mixture by the magnetic effect of the magnetic beads and catalyze the redox reactions between H 2 O 2 and TMB, generating quantitative electrochemical and colorimetric responses in homogeneous solution simultaneously. Under the optimized conditions, the linear range of both electrochemical (0.01 to 10 ng/ml) and colorimetric (0.01-15 ng/ml) channels can satisfy the demand of prostate-specific antigen detection in clinic (4 ng/ml), and the electrochemical and colorimetric channels have a low detection limit of 0.0079 ng/ml and 0.01 ng/ml respectively without using natural enzymes. The strategy by using synergetic PtNP@Co 3 O 4 hollow nanopolyhedrals as signal probes provides a promising scheme for developing simple, rapid, reliable, and ultrasensitive dual-channel homogeneous biosensors, which has a great potential as a powerful tool in prostate cancer diagnosis., (© 2021. Springer-Verlag GmbH Germany, part of Springer Nature.)

Immunotherapy of tumors has become a research hotspot. Tumor-associated macrophages (TAMs) are the most abundant interstitial cells in a tumor's microenvironment. As the concentration of the prepared nanoparticles increased, so their cytotoxicity of intensified. Under photothermal conditions, mAb-CD163/Au inhibited tumor invasion by killing M2 macrophages in vitro. After exposure to near-infrared (NIR) laser, mAb-CD163/Au inhibited tumor growth in vivo. The gold nanoparticles were modified to target M2 macrophages. Under NIR laser irradiation, mAb-CD163/Au achieved antitumor effects by killing M2 macrophages in vitro and in vivo., (© 2021. The Author(s), under exclusive licence to Springer-Verlag London Ltd. part of Springer Nature.)

This study presents the development of a sustainable production process of environmentally benign silver nanoparticles (AgNPs) from aqueous root extract of Rhodiola imbricata (RI) and Withania somnifera (WS) for mitigating environmental pollution and investigating their potential applications in agriculture and biomedical industry. RIWS-AgNPs were characterized using several analytical techniques (UV-Vis, DLS, HR-TEM, SAED, EDX and FTIR). The antioxidant and anticancer activity of RIWS-AgNPs were estimated by DPPH and MTT assay, respectively. UV-Vis and DLS analysis indicated that equal ratio of RIWS-extract and silver nitrate (1:1) is optimum for green synthesis of well-dispersed AgNPs (λ max : 430 nm, polydispersity index: 0.179, zeta potential: - 17.9 ± 4.14). HR-TEM and SAED analysis confirmed the formation of spherical and crystalline RIWS-AgNPs (37-42 nm). FTIR analysis demonstrated that the phenolic compounds are probably involved in stabilization of RIWS-AgNPs. RIWS-AgNPs showed effective catalytic degradation of hazardous environmental pollutant (4-nitrophenol). RIWS-AgNPs treatment significantly increased the growth and photosynthetic pigments of Hordeum vulgare in a size- and dose-dependent manner (germination (77%), chlorophyll a (12.62 ± 0.07 μg/ml) and total carotenoids (7.05 ± 0.04 μg/ml)). The DPPH assay demonstrated that RIWS-AgNPs exert concentration-dependent potent antioxidant activity (IC 50 : 12.30 μg/ml, EC 50 : 0.104 mg/ml, ARP: 959.45). Moreover, RIWS-AgNPs also confer strong cytotoxic activity against HepG2 cancer cell line in dose-dependent manner (cell viability: 9.51 ± 1.55%). Overall, the present study for the first time demonstrated a green technology for the synthesis of stable RIWS-AgNPs and their potential applications in biomedical and agriculture industry as phytostimulatory, antioxidant and anticancer agent. Moreover, RIWS-AgNPs could potentially be used as a green alternative for environmental remediation., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

An Au-based nanozyme composite (AuNPs/Cu,I) was constructed by using Cu,I-doped carbon dots (Cu,I-CDs) as the reducing agent as well as the nanozyme. Notably, AuNPs/Cu,I nanozyme not only possessed the intrinsic activity of mimicking enzymes of superoxide dismutase, peroxidase, and catalase at different conditions but was also employed as surface-enhanced Raman spectroscopy (SERS) enhancer. The combination of Cu,I-CDs and AuNPs promoted the electron transferability, leading to increased peroxidase-like activity and superoxide-like activity. Compared to the individual Cu,I-CDs and AuNPs nanozyme, the AuNPs/Cu,I composite demonstrated promising peroxidase-like activity by transferring electrons instead of generating OH. Interestingly, the multienzyme-like activity of AuNPs/Cu,I nanozyme could be finely tuned by changing the composition of Cu 0 /Cu + and Au. The tert-butyl hydroquinone (TBHQ) as the substrate could be catalyzed with AuNPs/Cu,I nanozyme to produce red substances, resulting in a significant Raman enhancement effect at the same time, showing good linear range from 0.11 to 10 mg L -1 . Overall, the current investigation provides a flexible and controllable way to design multifunctional nanozymes along with the Raman enhancement strategy based on the catalysis of nanozyme., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)