Carboxymethyl cellulose macromolecules as generator of anisotropic nanogold for catalytic performance

Hydroxyethylcellulose-Directed Synthesis of Gold Microplates with Hydrogen Peroxide in an Aqueous Phase

In this study, we successfully synthesized well-defined polygonal gold microplates for the first time in an aqueous phase using hydroxyethylcellulose (HEC) in the presence of hydrogen peroxide (H2O2). HEC played a pivotal role during the synthesis, acting not only as a biotemplate but also as an in situ reduction site for the nucleation and growth of gold (Au) microplates. H2O2 played a crucial role in accelerating the growth of Au microplates from the Au nucleus. This methodology is ecofriendly and easy to operate and has potential applications in various fields, such as electronics, photonics, and biotechnology.

Delivery of gold nanoparticle-conjugated M2e influenza vaccine in mice using coated microneedles

As a prospective influenza vaccination platform, a microneedle patch offers advantages such as self-administration and reduction of needle-phobia-associated vaccination avoidance. In an effort to design a broadly protective influenza vaccine we have previously developed a vaccine formulation containing the highly conserved ectodomain sequence of the M2 influenza protein (M2e) attached to the surface of gold nanoparticles (AuNPs) with CpG as a soluble adjuvant (AuNP-M2e + sCpG). Our previous studies have used the intranasal route for vaccination and demonstrated broad protection from this vaccine. Here we asked the question whether the same formulation can be effective when administered to mice using microneedles. We demonstrate that the microneedles can be coated with AuNP-M2e + sCpG formulation, and the AuNPs from the coating can be readily resuspended without aggregation. The AuNPs were delivered with high efficiency into murine skin, and the AuNPs cleared the skin within 12 h of microneedle treatment. After vaccination, strong M2e-specific humoral and cellular responses were stimulated, and the vaccinated mice were 100% protected following a lethal challenge with influenza A/PR/8/34 (H1N1).

The Potential Application of Green-Synthesized Metal Nanoparticles in Dentistry: A Comprehensive Review

Orodental problems have long been managed using herbal medicine. The development of nanoparticle formulations with herbal medicine has now become a breakthrough in dentistry because the synthesis of biogenic metal nanoparticles (MNPs) using plant extracts can address the drawbacks of herbal treatments. Green production of MNPs such as Ag, Au, and Fe nanoparticles enhanced by plant extracts has been proven to be beneficial in managing numerous orodental disorders, even outperforming traditional materials. Nanostructures are utilized in dental advances and diagnostics. Oral disease prevention medicines, prostheses, and tooth implantation all employ nanoparticles. Nanomaterials can also deliver oral fluid or pharmaceuticals, treating oral cancers and providing a high level of oral healthcare. These are also found in toothpaste, mouthwash, and other dental care products. However, there is a lack of understanding about the safety of nanomaterials, necessitating additional study. Many problems, including medication resistance, might be addressed using nanoparticles produced by green synthesis. This study reviews the green synthesis of MNPs applied in dentistry in recent studies (2010–2021).

Nanoengineering of eco-friendly silver nanoparticles using five different plant extracts and development of cost-effective phenol nanosensor

The production of environmentally friendly silver nanoparticles (AgNPs) has aroused the interest of the scientific community due to their wide applications mainly in the field of environmental pollution detection and water quality monitoring. Here, for the first time, five plant leaf extracts were used for the synthesis of AgNPs such as Basil, Geranium, Eucalyptus, Melia, and Ruta by a simple and eco-friendly method. Stable AgNPs were obtained by adding a silver nitrate (AgNO₃) solution with the leaves extract as reducers, stabilizers and cappers. Only, within ten minutes of reaction, the yellow mixture changed to brown due to the reduction of Ag⁺ ions to Ag atoms. The optical, structural, and morphology characteristics of synthesized AgNPs were determined using a full technique like UV-visible spectroscopy, FTIR spectrum, XRD, EDX spectroscopy, and the SEM. Thus, Melia azedarach was found to exhibit smaller nanoparticles (AgNPs-M), which would be interesting for electrochemical application. So, a highly sensitive electrochemical sensor based on AgNPs-M modified GCE for phenol determination in water samples was developed, indicating that the AgNPs-M displayed good electrocatalytic activity. The developed sensor showed good sensing performances: a high sensitivity, a low LOD of 0.42 µM and good stability with a lifetime of about one month, as well as a good selectivity towards BPA and CC (with a deviation less than 10%) especially for nanoplastics analysis in the water contained in plastics bottles. The obtained results are repeatable and reproducible with RSDs of 5.49% and 3.18% respectively. Besides, our developed sensor was successfully applied for the determination of phenol in tap and mineral water samples. The proposed new approach is highly recommended to develop a simple, cost effective, ecofriendly, and highly sensitive sensor for the electrochemical detection of phenol which can further broaden the applications of green silver NPs.

Melt intercalation technique for synthesis of hetero-metallic@chitin bio-composite as recyclable catalyst for prothiofos hydrolysis

The compatibility of homo-metallic and hetero-metallic bio-composite was promisingly investigated as recyclable catalyst for prothiofos hydrolysis. Chitin as water insoluble biopolymer was functionalized as a template for generation of homo-metallic (Ag@chitin, Au@chitin and Pd@chitin) and hetero-metallic (Au@Ag@chitin, Pd@Ag@chitin and Pd@Au@Ag@chitin) composites, by using melt intercalation technique. Investigation of the compatibility of the synthesized homo-metallic and hetero-metallic bio-composites in hydrolysis of prothiofos was performed and affirmed via HPLC results. Immobilization of Pd in the composites showed perfection in the catalytic performance for prothiofos hydrolysis. Pd@Au@Ag@chitin exhibited the highest hydrolysis result of 99% for prothiofos was hydrolyzed within 150 min with rate constant (k₁) of 24.48 min^-1. After five recycles for Pd@Au@Ag@chitin, the hydrolysis of prothiofos was lowered from 346 mg/g to 269 mg/g with reduction percentage of 22%. The synthesized bio-composite was highly effective as recyclable catalyst and can be easily served in the remediation of pesticides.

Fabrication and characterization of multi stimuli-responsive fibers via wet-spinning process

Luminescent fibers have attracted much attention due to their application in smart textiles for anti-counterfeiting, camouflage, fashion designs and so on. However, fibers with single function of luminescent is fail to meet the growing demand of smart textiles. Herein, we develop a multifunctional fiber with quick-responsive reversible photochromic and light-emitting with long afterglow. Doping with rare earth material SrAl₂O₄:Eu²⁺, Dy³⁺ phosphors and photochromic pigments into polyacrylonitrile (PAN) fibers enable by facile wet-spinning process, the properties of photochromic luminescent fibers were experimentally investigated in details. The results make clear that resulting fibers exhibit quick-responsive reversible photochromic properties and can be excited by a wide range of ray from 300 to 450 nm, displaying a wide band with a maximum peak at 525 nm. The photochromic pigments and SrAl₂O₄:Eu²⁺, Dy³⁺ phosphors distributed in fibers evenly and the fibers are stable below 258.76 °C. Persistent luminescent properties of fibers are excellent and the afterglow can last for more than 1 h. The ultimate strength of fibers are more than 1.39 MPa. Comparing with a lot of investigated luminescent fibers, our work to photochromic luminescent fibers show huge potential in anti-counterfeiting, aesthetics fashion designs and so on for smart textiles.

Studies of simultaneous electrochemical sensing of Hg2+ and Cd2+ ions and catalytic reduction properties of 4-nitrophenol by CuO, Au, and CuO@Au composite nanoparticles synthesised using a graft copolymer as a bio-template

Simultaneous electrochemical detection of Hg2+ and Cd2+ ions and catalytic reduction of 4NP to 4AP using a novel synthesized graft copolymer/CuO@Au NPs composite.

Decorated Au NPs on agar modified Fe3O4 NPs: Investigation of its catalytic performance in the degradation of methylene orange, and anti-human breast carcinoma properties

This work describes an eco-friendly approach for in situ immobilization of Au nanoparticles on the surface of Fe₃O₄ nanoparticles, with help of Agar and ultrasound irradiations, without using any toxic reducing and capping agents. The structure, morphology, and physicochemical properties were characterized by various analytical techniques such as Fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), inductively coupled plasma (ICP) and vibrating sample magnetometer (VSM). The desired catalyst showed great efficiency in the reductive degradation of methylene orange (MO) dye over NaBH₄ at room temperature. The MO was fully reduced in only 70 s and achieved rate constant of 9.6 × 10^-2 s^-1. The catalyst was reused for 10 runs without significant loss in catalytic activity. Cell viability of Fe₃O₄/agar/Au NPs was very low against breast adenocarcinoma (MCF7), breast carcinoma (Hs 578Bst), infiltrating ductal cell carcinoma (Hs 319.T), and metastatic carcinoma (MDA-MB-453) cell lines without any cytotoxicity on the normal cell line. According to the above findings, the Fe₃O₄/agar/Au NPs may be administrated for the treatment of several types of human breast carcinoma in humans.

Metal-dependent nano-catalysis in reduction of aromatic pollutants

Nanostructures have great potential in catalysis and their compositions may cause some interferences in the reactivity. Therefore, the present study focuses on comparison between three metallic nanoparticle-based Ag, Au, and Pd as nano-catalyst in reduction of aromatic pollutants. To neglect any interpenetration in their catalytic reactivity, the metallic nanoparticles were prepared via a consistent and reproducible one-step method with alkali-activated dextran. Interestingly, small sized/spherical AgNPs, AuNPs, and PdNPs were successively prepared with particle size of 3.4, 8.3, and 17.1 nm, respectively. The catalytic performance of the synthesized NPs was estimated for the reduction of p-nitroaniline and methyl red dye as different aromatic pollutants. Regardless of the particle size, there was a strong relation between catalytic action and the type of metal which followed the order of PdNP > AuNPs > AgNPs. Graphical Abstract.

Environmentally exploitable biocide/fluorescent metal marker carbon quantum dots

Carbon quantum dots are currently investigated to act as safe/potent alternatives for metal-based nanostructures to play the role of probes for environmental applications owing to their low toxicity, low cost, chemical inertness, biocompatibility and outstanding optical properties. The synthesis of biocide/fluorescent metal marker carbon quantum dots with hydrophilic character was performed via a quite simple and green technique. The natural biopolymer that was used in this study for the synthesis of carbon quantum dots is fragmented under strong alkaline conditions. Afterwards, under hydrothermal conditions, re-polymerization, aromatization and subsequent oxidation, the carbonic nanostructures were grown and clustered. Dialysis of the so-produced carbonic nanostructures was carried out to obtain highly purified/mono-dispersed carbon quantum dots with a size distribution of 1.5–6.5 nm. The fluorescence intensity of the synthesized carbon quantum dots under hydrothermal conditions for 3 h was affected by dialysis, however, the fluorescence intensity was significantly increased ca. 20 times. The synthesized carbon quantum dots were exploited as fluorescent markers in the detection of Zn²⁺ and Hg²⁺. The prepared carbon quantum dots also exhibited excellent antimicrobial potency against Bacillus cereus, Escherichia coli and Candida albicans. The detected minimal inhibitory concentration for the dialyzed CQDs towards the tested pathogens was 350–450 μL mL⁻¹. The presented approach is a simple and green technique for the scaled-up synthesis of biocide/fluorescent marker carbon quantum dots instead of metal-based nanostructures for environmental applications, without using toxic chemicals or organic solvents.

Synthesis of biocide/fluorescent metal marker carbon quantum dots with hydrophilic character for the detection of Zn²⁺ and Hg²⁺.

Carboxymethyl Chitosan Modified Carbon Nanoparticle for Controlled Emamectin Benzoate Delivery: Improved Solubility, pH-Responsive Release, and Sustainable Pest Control

Environmentally friendly pesticide delivery systems have drawn extensive attention in recent years, and they show great promise in sustainable development of agriculture. We herein report a multifunctional nanoplatform, carboxymethyl chitosan modified carbon nanoparticles (CMC@CNP), as the carrier for emamectin benzoate (EB, a widely used insecticide), and investigate its sustainable antipest activity. EB was loaded on CMC@CNP nanocarrier via simple physisorption process, with a high loading ratio of 55.56%. The EB@CMC@CNP nanoformulation showed improved solubility and dispersion stability in aqueous solution, which is of vital importance to its practical application. Different from free EB, EB@CMC@CNP exhibited pH-responsive controlled release performance, leading to sustained and steady EB release and prolonged persistence time. In addition, the significantly enhanced anti-UV property of EB@CMC@CNP further ensured its antipest activity. Therefore, EB@CMC@CNP exhibited superior pest control performance than free EB. In consideration of its low cost, easy preparation, free of organic solution, and enhanced bioactivity, we expect, CMC@CNP will have a brilliant future in pest control and green agriculture.

Photo-reduction of Ag nanoparticles by using cellulose-based micelles as soft templates: Catalytic and antimicrobial activities

Amphiphilic cellulose derivatives were synthesized from allyl cellulose (AC) and cystein (Cys)/n-dodecyl mercaptan (NDM) via the thiol-ene click reactions. The derivatives were self-assembled into micelles in distilled water, and the micelles sizes increased with an increase of the DS_NDM. The amphiphilic cellulose micelles were served as the soft templates for the controllable synthesis of Ag nanoparticles (NPs) through the photo-reduction. Ag NPs were embedded and stabilized by the amphiphilic cellulose micelles, and their sizes increased from 3.1 to 14.4 nm with an increase of the original template sizes. The catalytic properties of the Ag-loaded micelles were evaluated by the reduction of p-nitropheonl to p-aminophenol. The results demonstrated that the Ag-loaded micelles exhibited excellent catalytic activity. The reduction followed the first-order rate law, and the reaction constant decreased with increasing size of Ag NPs. Moreover, the Ag-loaded micelles displayed good antimicrobial activities to both S. aureus and E. coli. Therefore, the Ag-loaded cellulose-based micelles have potential applications in various fields.

Gold nanoparticle-carboxymethyl cellulose nanocolloids for detection of human immunodeficiency virus type-1 (HIV-1) using laser light scattering immunoassay

It is estimated that over 100 million people have been infected with human immunodeficiency virus (HIV-1) resulting in approximately 30 million deaths globally. Herein, we designed and developed novel nano-immunoconjugates using gold nanoparticles (AuNPs) and carboxymethylcellulose (CMC) biopolymer, which performed simultaneously as an eco-friendly in situ reducing agent and surface stabilizing ligand for the aqueous colloidal process. These AuNPs-CMC nanocolloids were biofunctionalized with the gp41 glycoprotein receptor (AuNPs-CMC-gp41) or HIV monoclonal antibodies (AuNPs-CMC_PolyArg-abHIV) for detection using the laser light scattering immunoassay (LIA). These AuNPs-CMC bioengineered nanoconjugates were extensively characterized by morphological and physicochemical methods, which demonstrated the formation of spherical nanocrystalline colloidal AuNPs with the average size from 12 to 20 nm and surface plasmon resonance peak at 520 nm. Thus, stable nanocolloids were formed with core-shell nanostructures composed of AuNPs and biomacromolecules of CMC-gp41, which were cytocompatible based on in vitro cell viability results. The AuNPs-CMC-gp41 nanoconjugates were tested against HIV monoclonal antibodies conjugates (AuNPs-CMC_PolyArg-abHIV) using the light scattering immunoassay (LIA) where they behaved as active nanoprobes for the detection at nM level of HIV-1 antigenic proteins. This strategy offers a novel nanoplatform for creating bioprobes using green nanotechnology for the detection of HIV-1 and other virus-related diseases.

Green synthesis of Ag@Au bimetallic regenerated cellulose nanofibers for catalytic applications

Highly active and reusable bimetallic Ag@Au/CNC nanocomposite was successfully obtainedviaa simple green synthesis for the reduction of nitrophenol and aza-Michael reaction.

One-step green approach for functional printing and finishing of textiles using silver and gold NPs

In this study, we present a successful simple method for printing and finishing of polyester and cotton fabrics using gold and silver nanoparticles (Au-NPs and Ag-NPs, respectively) as stable, fast colorants and functional components. The surface plasmon resonance (SPR) bands of the colloidal gold and silver NPs were observed at λ_max 520 nm and 450 nm, respectively, indicating the presence of spherical Au-NPs and Ag-NPs, which was further confirmed by TEM analysis. The printed samples were subjected to SEM, XRD and EDX analyses. The SEM images and EDX spectra unequivocally confirmed the existence of embedded NPs on the fabric surfaces. Both the cotton and polyester samples possessed excellent color fastness, as indicated from the color fastness test. The functional properties of the printed fabrics indicated that the incorporation of Au-NPs and Ag-NPs into the fabrics simultaneously imparted multifunctional properties such as stable brilliant colors, highly durable antimicrobial activity and very good UV-protection properties.

In this study, we present a successful simple method for printing and finishing of polyester and cotton fabrics using gold and silver nanoparticles (Au-NPs and Ag-NPs, respectively) as stable, fast colorants and functional components.