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Treating hazardous landfill leachate poses significant environmental challenges due to its complex nature. In this study, we propose a novel approach for enhancing the anaerobic digestion of landfill leachate using silver nanoparticles (Ag NPs) conjugated with eco-friendly green silica nanoparticles (Si NPs). The synthesized Si NPs and Ag@Si NPs were characterized using various analytical techniques, including transmission electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. The anaerobic digestion performance of Si NPs and Ag@Si NPs was tested by treating landfill leachate samples with 50 mg/L of each NP. The results demonstrated an enhancement in the biogas production rate compared to the control phase without the nanocomposite, as the biogas production increased by 14% and 37% using Si NPs and Ag@Si NPs. Ag@Si NPs effectively promoted the degradation of organic pollutants in the leachate, regarding chemical oxygen demand (COD) and volatile solids (VS) by 58% and 65%. Furthermore, microbial analysis revealed that Ag@Si NPs enhanced the activity of microbial species responsible for the methanogenic process. Overall, incorporating AgNPs conjugated with eco-friendly green Si NPs represents a sustainable and efficient approach for enhancing the anaerobic digestion of landfill leachate., 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 © 2024 Elsevier Ltd. All rights reserved.)

Water-soluble silver nanoclusters (AgNCs) as a new type of fluorescent material have attracted much attention for their remarkable optical properties and excellent cytocompatibility. However, it is still challenging to synthesize water-soluble AgNCs with good cytocompatibility and excellent fluorescence. Herein, the dialdehyde nanofibrillated cellulose (DANFC)- reduced water-soluble AgNCs capped by glutathione (GSH) with tunable fluorescence emissions were first reported. The DANFC provides a mild reduction environment and crystal growth system for the coordination between silver ions and GSH compared to conventional methods using strong reducing agents. The AgNCs with intense red fluorescence (R-AgNCs@GSH, size ∼2.24 nm) and green fluorescence (G-AgNCs@GSH, size ∼1.93 nm) were produced by varying the ratios of silver sources and ligands, and could maintain stable fluorescence intensity over 6 months. Moreover, the CCK-8 study demonstrated that the R-AgNCs@GSH and G-AgNCs@GSH reduced by DANFC of excellent cytocompatibility (cell viability >90 %) and enable precise multicolor intracellular imaging of Hela cells in 1 h. This work proposes a novel method to synthesize water-soluble AgNCs with tunable fluorescence emission at room temperature based on the classical silver- mirror reaction (SMR) using DANFC as reducing agent, and the synthesized fluorescent AgNCs have great potential as novel luminescent nanomaterials in biological research., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Metabolic acidosis-induced kidney injury (MAKI) is asymptomatic and lack of clinical biomarkers in early stage, but rapidly progresses to severe renal fibrosis and ultimately results in end-stage kidney failure. Therefore, developing rapid and noninvasive strategies direct responsive to renal tubular acidic microenvironment rather than delayed biomarkers are essential for timely renoprotective interventions. Herein, we develop pH-responsive luminescent gold nanoparticles (p-AuNPs) in the second near-infrared emission co-coated with 2,3-dimethylaleic anhydride conjugated β-mercaptoethylamine and cationic 2-diethylaminoethanethiol hydrochloride, which showed sensitive pH-induced charge reversal and intrarenal self-assembly for highly sensitive and long-time (~24 h) imaging of different stages of MAKI. By integrating advantages of pH-induced intrarenal self-assembly and enhanced interactions between pH-triggered positively charged p-AuNPs and renal tubular cells, the early- and late-stage MAKI could be differentiated rapidly within 10 min post-injection (p.i.) with contrast index (CI) of 3.5 and 4.3, respectively. The corresponding maximum CI could reach 5.1 and 9.2 at 12 h p.i., respectively. Furthermore, p-AuNPs were demonstrated to effectively real-time monitor progressive recovery of kidney injury in MAKI mice after therapy, and also exhibit outstanding capabilities for drug screening. This pH-responsive strategy showed great promise for feedback on kidney dysfunction progression, opening new possibilities for early-stage diagnosis of pH-related diseases., (© 2024 Wiley-VCH GmbH.)

Despite the widespread utilization of nano silver composites in the domain of catalytic hydrogenation of aromatic pollutants in wastewater, certain challenges persist, including the excessive consumption of chemical reagents during the preparation process and the difficulty in recycling. In this study, silver ions were reduced in-situ by taking advantage of the adsorptive and reducing capacities of hydroxyls and amino groups on lignin porous microspheres (LPMs) under mild ultrasonic conditions, and lignin porous microspheres loaded with silver nanoparticles (Ag@LPMs) were conveniently prepared. Ag@LPMs had excellent catalytic and cycling performances for p-nitrophenol (4-NP), methylene blue (MB) and methyl orange (MO). The 4-NP could be completely reduced to 4-AP within 155 s under the catalysis of Ag@LPMs, with a pseudo-first-order kinetic constant of 1.28 min -1 . Furthermore, Ag@LPMs could still complete the catalytic reduction of 4-NP within 10 min after five cycles. Ag@LPMs with the particle size ranging from 100 to 200 μm conferred ease of recycling, and the porous structure effectively resolved the issue of sluggish mass transfer encountered during the catalytic process. At the same time, the binding force of nano silver and LPMs obtained by ultrasonic was stronger than that of heating, so the materials prepared by ultrasonic had better cycling performance. Silver ions concentration and pH value in the preparation process affected the catalytic performance of Ag@LPMs, 50 mmol/L Ag + and pH value of 7 turned out to be the optimization conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

This study aimed to investigate a novel method for the green synthesis of iron nanoparticles (FeNPs) using marigold extract (Calendula officinalis L), kraft pulping black liquor, and nanocellulose. Then, the efficacy of FeNPs as a direct nanofertilizer on the growth parameters of marigold was investigated. Characterization techniques including FESEM, EDX, VSM, and FTIR were used to confirm the successful synthesis of FeNPs. The characterization results confirmed the formation and presence of FeNPs in the 20-100 nm range. FeNPs synthesized with nanocellulose notably enhanced marigold growth parameters compared to other materials. However, all nanoparticle variants, including those from marigold extract and black liquor, improved germination, plant height, root length, and plant dry weight compared to the control. Moreover, treatments exhibited higher available iron and total plant iron levels than the control. Thus, employing 10 mg FeNPs (prepared with 5.0 % nanocellulose) appears optimal for enhancing marigold growth and yield., 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 © 2024 Elsevier B.V. All rights reserved.)

Solar desalination is an effective solution to address the global water scarcity issue. However, biofouling poses a significant challenge for solar evaporators due to the presence of bacteria in seawater. In this study, an anti-biofouling evaporator was constructed using the synergistic antibacterial effect of lignin and silver nanoparticles (AgNPs). The AgNPs were easily synthesized using lignin as reductant under mild reaction conditions. Subsequently, the Lignin-AgNPs solution was integrated into polyacrylamide hydrogel (PAAm) without any purification steps, resulting in the formation of Lignin/AgNPs-PAAm (LAg-PAAm). Under the combined action of AgNPs and the hydroquinone groups present in oxidized lignin, LAg-PAAm achieved over 99 % disinfection efficiency within 1 h, effectively preventing biofilm formation in pore channels of solar evaporators. The anti-biofouling solar evaporator demonstrated an evaporation rate of 1.85 kg m -2  h -1 under 1 sun irradiation, and maintained stable performance for >30 days due to its high efficient bactericidal effect. Furthermore, it also exhibited exceptional salt-rejection capability attributed to its superior hydrophilicity., 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 © 2024 Elsevier B.V. All rights reserved.)

Given the widespread prevalence of viruses, there is an escalating demand for antimicrobial composites. Although the composite of dialdehyde cellulose and silver nanoparticles (DAC@Ag1) exhibits excellent antibacterial properties, its weak mechanical characteristics hinder its practical applicability. To address this limitation, cellulose nanofibers (CNFs) were initially ammoniated to yield N-CNF, which was subsequently incorporated into DAC@Ag1 as an enhancer, forming DAC@Ag1/N-CNF. We systematically investigated the optimal amount of N-CNF and characterized the DAC@Ag1/N-CNF using FT-IR, XPS, and XRD analyses to evaluate its additional properties. Notably, the optimal mass ratio of N-CNF to DAC@Ag1 was found to be 5:5, resulting in a substantial enhancement in mechanical properties, with a 139.8% increase in tensile elongation and a 33.1% increase in strength, reaching 10% and 125.24 MPa, respectively, compared to DAC@Ag1 alone. Furthermore, the inhibition zones against Escherichia coli and Staphylococcus aureus were significantly expanded to 7.9 mm and 15.9 mm, respectively, surpassing those of DAC@Ag1 alone by 154.8% and 467.9%, indicating remarkable improvements in antimicrobial efficacy. Mechanism analysis highlighted synergistic effects from chemical covalent bonding and hydrogen bonding in the DAC@Ag1/N-CNF, enhancing the mechanical and antimicrobial properties significantly. The addition of N-CNF markedly augmented the properties of the composite film, thereby facilitating its broader application in the antimicrobial field.

The current study aimed to evaluate the effects of biogenic silver nanoparticles (AgNPs) on growth behavior and leaf anatomy of in vitro growing shoots of 'Picual' and 'Dolce' olive cultivars. Biosynthesis of AgNPs was carried out using the cell-free filtrate of Fusarium oxysporum. The dimension and shape of the synthesized AgNPs have been analyzed using spectroscopy and topography analysis tools, confirming that the biosynthesis of AgNPs is a crystalline nanostructure with an average particle size of 37 nm. The shoots of the selected olive cultivars were cultured on Rugini olive medium-supplemented AgNPs at 0, 10, 20, and 30mg L - 1 . The effect of genotypes on shoot multiplication was significant, 'Picual' recorded higher values of shoot growth parameters compared with 'Dolce' cultivar. Adding AgNPs to the culture medium significantly affected the growth of in vitro olive shoots. AgNPs at 20 and 30mg L - 1 produced higher values of the number of shoots, shoot length, and leaf number of Picual cv. compared with the control treatments, but the higher AgNPs concentration harmed the growth parameters of Dolce cv. and recorded lower growth values compared with the lower concentration (10mg L - 1 ). AgNPs had a significant effect on leaf morphology and their anatomical structure. The current results showed that the stimulatory effect of AgNPs on shoot growth of in vitro olive shoots is highly dependent on plant genotype and nanoparticle concentration., (© 2024. The Author(s).)

Constructing a high-performance ultraviolet shielding film is an effective way for addressing the growing problem of ultraviolet radiation. However, it is still a great challenge to achieve a combination of multifunctional, excellent mechanical properties and low cost. Here, inspired by the multiscale structure of biomaterials and features of lignin, a multifunctional composite film (CNF/CMF/Lig-Ag) is constructed via a facile vacuum-filtration method by introducing micron-sized cellulose fibers (CMF) and lignin-silver nanoparticles (Lig-Ag NPs) into the cellulose nanofibers (CNF) film network. In this composite film, the microfibers interweave with nanofibers to form a multiscale three-dimensional network, which ensures satisfactory mechanical properties of the composite film. Meanwhile, the Lig-Ag NPs are employed as a multifunctional filler to enhance the composite film's antioxidant, antibacterial and ultraviolet shielding abilities. As a result, the prepared CNF/CMF/Lig-Ag composite film demonstrates excellent mechanical properties (with tensile strength of 133.8 MPa and fracture strain of 7.4 %), good biocompatibility, high thermal stability, potent antioxidant and antibacterial properties. More importantly, such composite film achieves a high ultraviolet shielding rate of 98.2 % for ultraviolet radiation A (UVA) and 99.4 % for ultraviolet radiation B (UVB), respectively. Therefore, the prepared CNF/CMF/Lig-Ag composite film shows great potential in application of ultraviolet protection., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Nanocomposites have been widely used in many important areas due to their particular physical/chemical properties; however, just though a simple technology, endowing multiple functions into a single nanomaterial for realizing their multifunctional applications is still a challenge. Here, we report a robust method for the facile synthesis of Ag-based multifunctional nanocomposites via using tannin-coated phenol-formaldehyde resin nanospheres (TA-PFRN) as silver nanoparticle (Ag NP) carriers. The thickness of the tannin coating is readily tuned from 50 to 320 nm by regulating the concentration of tannin added. Under the optimal conditions, the TA-PFRN has a 23.8 wt % of Ag NPs loading capacity with only 17.2 nm Ag NP layers. Consequently, the novel TA-PFRN@Ag nanocomposites possess multiple functions and integrated characteristics. As catalysts, the catalytic efficiency of TA-PFRN@Ag is nearly 6 times higher than that of the PFRN@Ag. As highly effective free radical initiators, TA-PFRN@Ag nanocomposites can trigger ultrafast acrylic acid (AA)/acrylamide (AM) polymerization at room temperature (in only a few minutes). As nano-reinforced fillers, the addition of 0.04 wt % nanocomposites can improve the tensile strength of PVA film from 60 to 153.2 MPa. In addition, the nanocomposites can also serve as antibacterial agents, efficiently inhibiting the growth of Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ); as antiultraviolet agents, the presence of TA-PFRN@Ag nanocomposites endows the film/hydrogel materials excellent ultraviolet (UV) shielding. This work provides a novel strategy for the green synthesis of Ag-based multifunctional nanocomposites that show promising applications in catalysis, nanomaterials, and biomedicine.

In this study, novel crosslinked hydrogels based on chitosan (CS) and carrageenan (CRG) loaded with silver and/or copper nanoparticles (Ag/CuNPs) were prepared through a freeze-drying (thawing) process to be applied in biological applications comprising wound dressing. These hydrogels showed porous interconnected structures. The influence of the used nanoparticles (NPs) on the antibacterial properties of the CS/CRG hydrogels was explored. Antimicrobial results revealed that both CS/CRG/CuNPs, CS/CRG/AgNPs, and CS/CRG/Ag-CuNPs exhibited promising antibacterial and antifungal activity against Escherichia coli, Pseudomonas aeruginosa, Streptococcus mutans, Staphylococcus aureus, Bacillus subtilis, and Candida albicans. Moreover, CS/CRG/AgNPs, CS/CRG/CuNPs, and CS/CRG/Ag-CuNPs hydrogels showed potential antioxidant activity to be 57%, 78%, and 89%, respectively. Furthermore, cytotoxicity results against Vero normal cell line confirmed that all designed hydrogels are safe upon usage. The bimetallic CS/CRG hydrogels showed notably enhanced antibacterial properties among the as-prepared hydrogels allowing them to be a successful material upon being employed in wound dressing applications., (© 2023 Wiley-VCH GmbH.)

Microcystins with leucine arginine (MC-LR) is a virulent hepatotoxin, which is commonly present in polluted water with its demethylated derivatives [Dha 7 ] MC-LR. This study reported a low-cost molecularly imprinted polymer network-based electrochemical sensor for detecting MC-LR. The sensor was based on a three-dimensional conductive network composed of multi-walled carbon nanotubes (MWCNTs), graphene quantum dots (GQDs), and gold nanoparticles (AuNPs). The molecularly imprinted polymer was engineered by quantum chemical computation utilizing p-aminothiophenol (p-ATP) and methacrylic acid (MAA) as dual functional monomers and L-arginine as a segment template. The electrochemical reaction mechanism of MC-LR on the sensor was studied for the first time, which is an irreversible electrochemical oxidation reaction involving an electron and two protons, and is controlled by a mixed adsorption-diffusion mechanism. The sensor exhibited a great detection response to MC-LR in the linear range of 0.08-2 μg/L, and the limit of detection (LOD) is 0.0027 μg/L (S/N = 3). In addition, the recoveries of the total amount of MC-LR and [Dha 7 ] MC-LR in the actual sample by the obtained sensor were in the range from 91.4 to 116.7%, which indicated its great potential for environmental detection.

Paper coating plays an important role in the paper properties, printability and application. The nanocoating is a multifunction layer that provides the paper with unique features. In this work, nanocoating formulas were prepared using a green method and component. The nanocoating formulas were based on biopolymers nanostarch NSt and nanochitosan NCh (NCS) decorated with Egyptian kaolinite Ka doped with zinc nanoparticles NCS@xka/ZnONPs (x represents different ratios) support for multifunctional uses. The nanocoating formulas were characterized using a physiochemical analysis as well as a topographical study. FTIR, XRD, SEM and TEM techniques were used. Additionally, the antimicrobial activity of the tested samples was assessed against six microorganisms including Gram-negative and Gram-positive bacteria. The prepared nanocoating formulas affirmed excellent antimicrobial activity as a broad-spectrum antimicrobial active agent with excellent activity against all representative microbial communities. The nanocoating with the highest ratio of Ka/ZnONPs (NCS@40 ka/ZnONPs) showed excellent antimicrobial activity with an inhibition percentage of more than 70% versus all microorganisms presented. The paper was coated with the prepared suspensions and characterized concerning optical, mechanical and physical properties. When Ka/ZnONPs were loaded into NCS in a variety of ratios, the characteristics of coated paper were enhanced compared to blank paper. The sample NCS@40 ka/ZnONPs increased tensile strength by 11%, reduced light scattering by 12%, and improved brightness and whiteness by 1%. Paper coated with NCh suspension had 35.32% less roughness and 188.6% less porosity. When coated with the sample NCS@10 ka/ZnONPs, the coated paper's porosity was reduced by 94% and its roughness was reduced by 10.85%. The greatest reduction in water absorptivity was attained by coating with the same sample, with a reduction percentage of 132%., (© 2023. The Author(s).)

Recently, antimicrobial resistance has increased globally particularly Candida infections. Most of antifungal drugs used for treating candidiasis became resistant to most of Candida species. In the current study, a nanocomposite based on mycosynthesized copper oxide nanoparticles (CuONPs), nanostarch, nanochitosan was prepared. Results illustrated that twenty-four Candida isolates were isolated from clinical samples. Furthermore, three Candida strains were selected as the most resistant among others toward commercial antifungal drugs; these selected strains were identified genetically as C. glabrata MTMA 19, C. glabrata MTMA 21 and C. tropicalis MTMA 24. Characterization of the prepared nanocomposite was carried out using physiochemical analysis included Ultraviolet-visible spectroscopy (Uv-Vis), Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX) and Transmission Electron Microscopy (TEM). Moreover, the nanocomposite exhibited promising anticandidal activity against C. glabrata MTMA 19, C. glabrata MTMA 21 and C. tropicalis MTMA 24, where the inhibition zones were 15.3, 27 and 28 mm, respectively. Ultrastructure changes observed in nanocomposite-treated C. tropicalis demonstrated disruption of the cell wall which led to cell death. In conclusion, our results confirmed that the novel biosynthesized nanocomposite based on mycosynthesized CuONPs, nanostarch and nanochitosan is a promising anticandidal agent to fight multidrug-resistant Candida., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2023. Published by Elsevier B.V.)

The diagnosis and treatment of many neurological and psychiatric problems depend on establishing simple, inexpensive, and comfortable electrochemical sensors for dopamine (DA) detection. Herein, 2,2,6,6 tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOC) were successfully loaded with silver nanoparticles (AgNPs) and/or graphite (Gr) and crosslinked by tannic acid, producing composites. This study describes a suitable casting procedure for the composite synthesis of TOC/AgNPs and/or Gr for the electrochemical detection of dopamine. Electrochemical impedance spectra (EIS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to characterize the TOC/AgNPs/Gr composites. In addition, the direct electrochemistry of electrodes treated with the prepared composites was examined using cyclic voltammetry. The TOC/AgNPs/Gr composite-modified electrode improved electrochemical performance towards detecting dopamine compared to TOC/Gr-modified electrodes. Upon employing amperometric measurement, our electrochemical instrument has a wide linear range (0.005-250 μM), a low limit of detection (0.0005 μM) at S/N = 3, and a high sensitivity (0.963 μA μM -1  cm -2 ). Additionally, it was demonstrated that DA detection seemed to have outstanding anti-interference characteristics. The proposed electrochemical sensors meet the clinical criteria regarding reproducibility, selectivity, stability, and recovery. The straightforward electrochemical method utilized in this paper may provide a potential framework for creating dopamine quantification biosensors., 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 © 2023 Elsevier B.V. All rights reserved.)

The demand for antimicrobial materials is gradually increasing due to the threat of infections and diseases caused by microorganisms. Silver nanoparticles (AgNPs) are widely used because of their broad-spectrum antimicrobial properties, but their synthesis methods are often environmentally harmful and AgNPs difficult to isolate, which limits their application in several fields. In this study, an aqueous solution of dialdehyde cellulose (DAC) was prepared and used as a reducing agent to synthesize AgNPs in an efficient and environmentally friendly process. The synthesized AgNPs can be easily separated from the reducing agent to expand their applications. In addition, the AgNPs were immobilized in situ on dialdehyde cellulose to form antibacterial composite films. The results showed that the prepared silver nanoparticles were mainly spherical and uniformly dispersed, with an average size of about 25 nm under optimal conditions. Moreover, the dialdehyde cellulose-nanosilver (DAC@Ag) composite films had excellent mechanical properties, positive transparency, ultraviolet-blocking properties, and effective antibacterial activity against E. coli and S. aureus . Notably, the composite films exhibited excellent oxygen and water vapor barrier properties, with WVT and ORT of 136.41 g/m 2 ·24 h (30 °C, 75% RH) and <0.02 cm 3 /m 2 ·24 h·0.1 MPa (30 °C, 75% RH), respectively, better than commercial PE films. Hence, this study not only provides an environmentally friendly method for the preparation of silver nanoparticles, but also offers a simple and novel strategy for the in situ synthesis of silver-loaded antibacterial composite films.

Bacterial infection has become one of the major threats to human health all over the world, and the development and application of antibacterial materials has drawn great attention. Based on the Schiff-base structure, ZnONPs@ACFs are obtained by loading zinc oxide nanoparticles (ZnONPs) on amino cellulose fibers (ACFs) in-situ through the coordination of amino groups with metal ions. The results of FT-IR, XRD and UV-vis demonstrate that ZnONPs are successfully loaded and uniformly dispersed on ACF surface, and the ACFs maintain intact morphology observed by SEM. Furthermore, the zero-span tensile strength of ZnONPs@ACFs is 66.48 N/cm (ROL: 24.98 N/cm/s) under the optimum conditions, which indicates that ZnONPs@ACFs have a certain strength and can be used to make antibacterial sheet materials via paper-making wet-forming process. Accordingly, the ZnONPs@ACF composites show inhibition zones of 4.95 mm and 1.10 mm against E. coli and S. aureus, respectively. The new cellulose-based antibacterial materials demonstrate potential applications in the field of food packaging and biological medicine etc., 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. Published by Elsevier B.V.)

The size of silver nanoparticles (Ag NPs) and loading amount of Ag NPs onto their substrate/carrier are two key factors for their efficient applications. Herein, we present a facile method for in situ synthesizing ultrafine and highly loaded Ag NPs on the surface of tannin-coated catechol-formaldehyde resin (TA-CFR) nanospheres. TA-CFR nanospheres act as green and highly efficient reducing agents for converting silver ions (Ag + ) into Ag NPs, and the size of resultant Ag NPs is only ∼ 7.5 nm, and the Ag NPs loading capacity of TA-CFR is as high as 61.5 wt%, both of which contribute to the very high specific surface area of Ag NPs. Consequently, the as-synthesized TA-CFR@Ag composites show high catalytic performance, and the catalytic rate for the reduction of 4-nitrophenol is almost 10 times higher than that of the control. Meanwhile, TA-CFR@Ag composites also possess high antibacterial activity, efficiently inhibiting the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Furthermore, tannin coating (thickness: ∼ 15 nm) minimizes the aggregation of Ag NPs, and enhances the reusability and stability of resultant Ag NPs, because of their high surface charges (the zeta potential is up to -65.5 ± 1.9 mV) and strong coordination capability with Ag NPs. This work provides a new frontier to develop multifunctional nanomaterials focusing on the green catalyst synthesis and environmental-remedy applications., 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 Inc. All rights reserved.)

This study aimed to determine the efficacy of novel ultrafiltration and mixed matrix membrane (MMM) composed of hydrous manganese oxide (HMO) and silver nanoparticles (Ag-NPs) for the removal of biological oxygen demand (BOD) and chemical oxygen demand (COD). In the polycarbonate (PC) MMM, the weight percent of HMO and Ag-NP has been increased from 5% to 10%. A neural network (ANN) was used in this study to compare PC-HMO and Ag-NP. MMM was evaluated in combination with HMO and Ag-NP loadings in order to assess their effects on pure water flux, mean pore size, porosity, and efficacy in removing BOD and COD. HMO and Ag-NPs can decrease membrane porosity in the casting solution while increasing mean pore size. According to the study's findings, the artificial neural network model appears to be highly appropriate for predicting the removal of BOD and COD. To develop a successful model, a suitable input dataset was selected, which consisted of BOD and COD. An ideal model architecture for MMM was proposed based on an optimal number of hidden layers (2 layers) and neurons (5-8 neurons). Experiments and predicted data show a strong correlation between the developed models. BOD was predicted with an excellent R2 and a low root mean square error (RMSE) of 0.99 and 0.05%, respectively, while COD was predicted with an excellent R2 and a low RMSE of 0.99 and 0.09%, respectively. Based on the results, Ag-NP was found to be an excellent candidate for the preparation of MMMs as well as convenient for the removal of BOD and COD from polluted water sources., 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.)

The development of shape-memory sponge dressings with functions, such as hemostasis, antibacterial activity, and wound healing, is of great significance in clinical applications. Herein, a novel AuNPs@corn stalk/chitin composite sponge (CCAu) was fabricated by crosslinking the chitin matrix with corn stalk-embedded gold nanoparticles (AuNPs). The addition of AuNPs@corn stalk gave the porous chitin sponge shape-recovery ability with improved softness, porosity, and water absorption. Correspondingly, the composite sponge showed better hemostatic effects than commercial PVF sponges. The photothermal effect of AuNPs endowed the composite sponge with excellent antibacterial activity. In addition, the wound treated with composite sponge containing antioxidant AuNPs exhibited a significantly faster wound healing rate (reaching 41.6 % on day 3) than the CH (33.2 %) and control (12.6 %) group through promoting cell migration, angiogenesis and collagen deposition. Therefore, the multifunctional composite sponge with great biocompatibility in this work provides a potential strategy for wound healing., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The promising features of most bacterial celluloses (BC) promote the continuous mining for a cost-effective production approach toward wide and sustainable applications. Herein, cantaloupe peels (CP) were successfully implemented for sustainable BC production. Results indicated that the enzymatically hydrolyzed CP supported the maximum BC production of approximately 3.49 g/L when used as a sole fermentation media. The produced BC was fabricated with polyvinyl alcohol (PVA) and chitosan (Ch), and loaded with green synthesized copper oxide nanoparticles (CuO-NPs) to improve its biological activity. The novel composite showed an antimicrobial activity against several human pathogens such as Staphylococcus aureus, Streptococcus mutans, Salmonella typhimurium, Escherichia coli, and Pseudomonas fluorescens. Furthermore, the new composite revealed a significant in vitro anticancer activity against colon (Caco-2), hepatocellular (HepG-2), and breast (MDA) cancer cells, with low IC 50 of 0.48, 0.27, and 0.33 mg/mL for the three cell lines, respectively. On the other hand, the new composite was remarkably safe for human skin fibroblast (HSF) with IC 50 of 1.08 mg/mL. Interestingly, the composite membranes exhibited lethal effects against all stages of larval instar and pupal stage compared with the control. In this study, we first report the diverse potential applications of BC/PVA/Ch/CuO-NPs composites based on green synthesized CuO-NPs and sustainably produced BC membrane., (© 2022. The Author(s).)

Recently, cellulose nanocrystals (CNs) have attracted wide attention owing to their superior properties compared to their bulk materials. For example, they represent an outstanding model for fabricating green metallic/metal oxide nanoparticles (NPs). In this study, two CNs (carboxylated CNs and sulfated CNs) extracted from agro-wastes of palm sheath fibers were used as templates for the facile and green synthesis of ZnO NPs by employing the sono-co-precipitation method. The obtained nanomaterials were characterized using TEM, EDX, UV-visible, DLS, FT-IR, and XRD analysis. As a result, the size and concentration of synthesized ZnO NPs were inversely proportional to one another and were affected by the CNs utilized and the reaction temperature used. Contagious diseases incited by multifarious toxigenic bacteria present severe threats to human health. The fabricated bio-nanocomposites were evaluated in terms of their antimicrobial efficacy by agar well diffusion method and broth microdilution assay, showing that CN-ZnO bio-nanocomposites were effective against the tested Gram-negative (Escherichia coli and Salmonella) and Gram-positive (Listeria monocytogenes and Staphylococcus aureus) bacteria. The influence of the subinhibitory concentrations of these suspensions on the expression of the most critical virulence toxin genes of the tested strains was effective. Significant downregulation levels were observed through toxigenic operons to both fabricated CN-ZnO bio-nanocomposites with a fold change ranging from 0.004 to 0.510, revealing a decline in the capacity and virulence of microorganisms to pose infections. Therefore, these newly fabricated CNS-ZnO bio-nanocomposites could be employed rationally in food systems as a novel preservative to inhibit microbial growth and repress the synthesis of exotoxins., (© 2022. The Author(s).)

In this work, the effect of using Ag-doped TiO 2 nanopigments on optical, mechanical and antimicrobial properties of coated paper was explored. Furthermore, the long-term antimicrobial activity of the coated paper was examined for up to 25 years. Titanium dioxide (TiO 2 ) nanoparticles have been synthesized and doped with different percentages of Ag nanoparticles (Ag NPs) using a simple wet chemical approach. The Ag@TiO 2 modified nanopigments were in the form of nanorods with an average size of about 20 nm as observed from TEM images. Increasing Ag content from 0.01 to 1.0% showed an increase in the mechanical properties of coated paper in terms of tensile, stretching, tensile energy absorption and burst while preserving the optical properties. Moreover, the antimicrobial inhibition activity increased with increasing the Ag content. The 1% Ag@TiO 2 showed a long-lasting antimicrobial effect against Staphylococcus aureus (S. aureus) Gram-positive bacteria even after 25 years of ageing (93.4% inhibition). Investigation of reactive oxygen species (ROS) generation and reaction mechanism of antimicrobial activity over Ag/TiO 2 under visible light is proposed. These results suggest that Ag/TiO 2 NPs can be potentially used as a disinfection coating for paper and improving its mechanical properties., (© 2022. The Author(s).)

The ever increasing concentration of toxic and carcinogenic hexavalent chromium (Cr (VI)) in various environmental mediums including water-bodies due to anthropogenic activities with rapid civilization and industrialization have become the major issue throughout the globe during last few decades. Therefore, developing new strategies for the treatment of Cr(VI) contaminated wastewaters are in great demand and have become a topical issue in academia and industry. To date, various techniques have been used for the remediation of Cr(VI) contaminated wastewaters including solvent extraction, adsorption, catalytic reduction, membrane filtration, biological treatment, coagulation, ion exchange and photo-catalytic reduction. Among these methods, the transformation of highly toxic Cr(VI) to benign Cr(III) catalyzed by metallic nanoparticles (M-NPs) with reductant has gained increasing attention in the past few years, and is considered to be an effective approach due to the superior catalytic performance of M-NPs. Thus, it is a timely topic to review this emerging technique for Cr(VI) reduction. Herein, recent development in synthesis of M-NPs based non-supported, supported, mono-, bi- and ternary M-NPs catalysts, their characterization and performance for the reduction of Cr(VI) to Cr(III) are reviewed. The role of supporting host to stabilize the M-NPs and leading to enhance the reduction of Cr(VI) are discussed. The Cr(VI) reduction mechanism, kinetics, and factors affecting the kinetics are overviewed to collect the wealthy kinetics data. Finally, the challenges and perspective in Cr(VI) reduction catalyzed by M-NPs are proposed. We believe that this review will assist the researchers who are working to develop novel M-NPs catalysts for the reduction of Cr(VI)., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Pyrolysis is one of the most widely utilized protocols for the preparation of nanoconfined metal species for heterogeneous catalysis, but it still suffers from the uncontrollable composition evolution process with undesired metal sintering and porous structure collapse. Herein, a novel and versatile molten salt-assisted pyrolysis strategy was demonstrated for the preparation of ultrasmall transition-metal nanoparticles embedded in hollow hierarchical carbon skeletons. The preparation only involved the fabrication of metal-organic framework templates and subsequent pyrolysis with the addition of KCl-KBr molten salt, which played a crucial role in pore size extending and metal sintering inhibiting. Benefitting from the encapsulation effect, the as-synthesized Cu@HHC materials exhibited remarkable catalytic performance and recycling stability in the selective oxidation of biomass-derived 5-hydroxymethylfurfural into 2,5-diformylfuran under mild reaction conditions., (© 2022 Wiley-VCH GmbH.)

This study shows the effective use of MXene-based nanomaterials to improve the performance of biocomposite sponges in wound healing. In this way, diverse chitin/MXene composite sponges are fabricated by incorporating MXene-based nanomaterials with various morphology (accordion-shaped, intercalated, single-layer, gold nanoparticles (AuNPs)-loaded single-layer) into the network of chitin sponge (CH), which can prevent massive blood losses and promote the healing process of bacterial-infected wounds. With the addition of MXene-based nanomaterials, the hemostatic efficacy of CH is enhanced due to the improved hemophilicity and accelerated blood coagulation kinetics. Furthermore, the composite sponges show a predominant antibacterial activity through the synergy between the capture and the photothermal effects. Importantly, the addition of AuNPs to composite sponges further improves hemostatic performance and promotes normal skin cell migration to heal the infected wound, achieving wound closure rates of 84% on day 9. These initial studies expand the applications of MXene-based nanomaterials in biomedical fields., (© 2022 Wiley-VCH GmbH.)

For the high-valued utilization of hemicelluloses and for realizing the controllable synthesis of NPs, this paper's aim is to combine xylan, chitosan and nanometal materials at the same time. In this research study, firstly, propargyl xylan was synthesized via nucleophilic substitution reaction between xylan and propargyl bromide in NaOH solution. On the other hand, a tosyl group was introduced onto the 6th position of synthesized quaternized chitosan (QCS), and the azide group replaced the tosyl group to obtain 6-amido-QCS (QCS-N 3 ). The synthesis conditions of the above reactions were optimized. Subsequently, the novel xylan-click-QCS polymer was obtained via click reaction between terminal alkyne groups on the xylan chains and azide groups on QCS. Then, AgNPs and AuNPs were synthesized by adopting the xylan-click-QCS polymer as the reducing and stabilizing agent, and the reaction conditions were optimized to obtain well-dispersed and highly stable nanoparticles. There were two kinds of Ag nanomaterials, with diameters of 10~20 nm and 2~5 nm, respectively, indicating the formation of Ag nanoclusters, except for Ag nanoparticles, in this reaction. The diameter of the synthesized AuNPs was 20~30 nm, which possessed a more uniform size distribution. The Ag nanoclusters with a smaller size (2~5 nm) could inhibit MCF-7 cell proliferation effectively, indicating their application potential in cancer therapy. The study gives a new approach to the high-value utilization of biopolymers.

Surface-enhanced Raman spectroscopy (SERS) has been identified as a fundamental surface-sensitive technique that boosts Raman scattering by adsorbing target molecules on specific surfaces. The application of SERS highly relies on the development of smart SERS substrates, and thus the fabrication of SERS substrates has been constantly improved. Herein, we investigate the impacts of different substrates on SERS technology including plasmonic metal nanoparticles, semiconductors, and hybrid systems in quantitative food safety and quality analysis. We first discuss the fundamentals, substrate designs, and applications of SERS. We then provide a critical review of the recent progress of SERS in its usage for screening and detecting chemical and biological contaminants including fungicides, herbicides, insecticides, hazardous colorants, and biohazards in food samples to assess the analytical capabilities of this technology. Finally, we investigate the future trends and provide practical techniques that could be used to fulfill the requirements for rapid analysis of food at a low cost.

In recent years, polysaccharides-based nanocomposites have been used for biomedical applications. In the current study, a nanocomposite based on myco-synthesized copper nanoparticles (CuNPs) and starch was prepared. The prepared nanocomposite was fully characterized using UV-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), mapping, transmission electron microscope (TEM), and dynamic light scattering (DLS). Results revealed that this nanocomposite is characterized by nano spherical shape ranged around 200 nm as well as doped with CuNPs with size about 9 nm. Antimicrobial, antioxidant, and anticancer activities of the prepared nanocomposite were evaluated. Results revealed that CuNPs-based nanocomposite exhibited outstanding antibacterial and antifungal activity toward Escherichia coli ATCC25922, Bacillus subtilis ATCC605, Candida albicans ATCC90028, Cryptococcus neoformance ATCC 14,116, Aspergillus niger RCMB 02,724, A. terreus RCMB 02,574, and A. fumigatus RCMB 02,568. Moreover, CuNPs-based nanocomposite has a strong antioxidant activity as compared to ascorbic acid, where IC 50 was 18 µg/mL. Cytotoxicity test of CuNPs-based nanocomposite revealed that this nanocomposite is safe in use, where IC 50 was 185.1 µg/mL. Furthermore, CuNPs-based nanocomposite exhibited potential anticancer activity against MCF7 cancerous cell line where IC 50 was 62.8 µg/mL which was better than CuNPs alone. In conclusion, the prepared CuNPs with starch-based nanocomposite is promising for different biomedical applications as antimicrobial, antioxidant, and anticancer activities., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Semiconductor metal-oxide/metal heterostructures with synergetic properties have potential applications in photocatalysis and optical sensors. Here, Cu 2 O sub-micro cubes were synthesized under environmentally benign conditions using 2, 2, 6, 6-tetramethylpyperdine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils as a reducing and stabilizing agent. Then the surface of the Cu 2 O cubes was decorated with silver nanoparticles (AgNPs) by a substitution reaction. The Cu 2 O/Ag heterostructures within the cellulose nanofibrils (CNFs) network were employed as a promising surface-enhanced Raman scattering (SERS) assay for efficient sensing of methylene blue (MB), reaching a maximum enhancement factor (EF) of 4.0 × 10 4 . Their SERS intensities depended on the coverage density of AgNPs and the wavelength of the excitation laser. The excellent SERS performance may result from the charge transfer between Ag and Cu 2 O molecules and the strong electromagnetic field at the interface. The CNF-Cu 2 O/Ag substrates were capable of detecting MB dye down to 10 -8  M level with a relative standard deviation of 10-15%, demonstrating great sensitivity and reproducibility., (Copyright © 2022. Published by Elsevier B.V.)

As a natural antitumor drug, curcumin (CUR) has received increasing attention from researchers and patients due to its various medicinal properties. However, currently CUR is still restricted due to its low and stand-alone therapeutic effects that seriously limit its clinical application. Here, by using cellulose nanocrystals (CNCs) as a nanocarrier to load CUR and AuNPs simultaneously, we developed a hybrid nanoparticle as a codrug delivery system to enhance the low and stand-alone therapeutic effects of CUR. Aided with the encapsulation of β-cyclodextrin (βCD), both the solubility and the stability of CUR are greatly enhanced (solubility increased from 0.89 to 131.7 μg/mL). Owing to the unique rod-like morphology of CNCs, the system exhibits an outstanding loading capacity of 31.4 μg/mg. Under the heat effects of coloaded AuNPs, the system demonstrates a high release rate of 77.63%. Finally, with CNC as a bridge nanocarrier, all aforementioned functions were integrated into one hybrid nanoparticle. The all-in-one integration ensures CUR to have enhanced therapeutic effects and enables the delivery system to exhibit combined chemo-photothermal therapy outcomes. This work presents a significant step toward CUR's clinical application and provides a new strategy for effective and integrative treatment of tumor disease.

Recently, versatile hydrogels with multifunctionality have been widely developed with emerging applications as wearable and implantable devices. In this work, we reported novel versatile hydrogels by self-catalyzing the gelation of an interpenetrating polymer network consisting of acrylic acid (AA) monomers and GA-modified collagen (GCOL) in situ decorated silver nanoparticles (AgNPs). The resultant hydrogel, namely AgNP@GCOL/PAA, has many desirable features, including good mechanical properties (such as 123 kPa, 916%, and 1961 J m -2 for the fracture stress, strain and tearing energy) that match with those of animal skin, excellent self-healing performance, favorable conductivity and strain sensitivity as a flexible biosensor, and excellent antibacterial and anti-UV properties, as well as the strong adhesiveness on skin. Moreover, AgNP@GCOL/PAA showed excellent biocompatibility via in vitro cell culture. Remarkably, AgNP@GCOL/PAA displayed superior hemostatic properties with sharply decreasing blood loss for a mouse liver incision, closely related to its strong self-adhesion which produced anchoring strength to the bleeding site and thus formed a network barrier with liver tissue. This study provides new opportunities for the facile preparation of widely used multifunctional collagen-based hydrogels based on a simple pyrogallol-Ag system.

The use of functional biodegradable wastes to treat environmental problems would create minimal extra burden to our environment. In this paper, we propose a sustainable and practical strategy to turn spent coffee ground (SCG) into a multifunctional palladium-loaded catalyst for water treatment instead of going into landfill as solid waste. Bleached delignified coffee ground (D-SCG) has a porous structure and a good capability to reduce Pd (II) to Pd (0). A large amount of nanocellulose is formed on the surface of SCG after bleaching by H 2 O 2 , which anchors and disperses the palladium nanoparticles (Pd NPs). The D-SCG loaded with Pd NPs (Pd-D-SCG) is superhydrophilic, which facilitates water transport and thus promotes efficient removal of organic pollutants dissolved in water. Pd-D-SCG exhibits excellent room temperature catalytic activity for the removal of 4-nitrophenol (4-NP) and methylene blue (MB) in water and shows good chemical stability and recyclability in water, with no obvious decrease even after five repeated cycles., 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 © 2021 Elsevier Inc. All rights reserved.)

A highly sensitive electrochemical sensor was developed through a one-pot green synthesis method for nitrite detection based on the electrochemical technique. Xylan-based carbon quantum dots (CQDs) were used as green in situ reducing agent to prepare CQDs capped gold nanoparticles (Au@CQDs). MXene of good electrical conductivity was used as the immobilized matrix to fabricate Au@CQDs-MXene nanocomposites with the advantages of good electrical conductivity and electrocatalysis. An electrochemical sensor for nitrite monitor was obtained by loading the Au@CQDs-MXene on a glassy carbon electrode. The sensor presents high sensitivity, good stability, wide linear range, and excellent selectivity due to the high catalytic activity of AuNPs and CQDs, the large specific surface area of MXene, and exceptional electrical conductivity of AuNPs and MXene. Under the optimal condition, the linear detection range of the sensor was from 1 μM to 3200 μM with a detection limit of 0.078 μM (S/N = 3), which was superior to most reported sensors using differential pulse voltammetry (DPV) method. Furthermore, this sensor was successfully applied to detect nitrite in tap water and salted vegetables with satisfactory recoveries. This modified electrocatalytic sensor shows a new pathway to fabricate nitrite detection sensor with feasibility for practical application., 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 © 2021 Elsevier Inc. All rights reserved.)

In this study, we report the development of physically cross-linked hydroxyethyl cellulose grafted polyacrylic acid-co-polyacrylamide/silver nanocomposite [Ag@HEC-g-P(AA-co-AM)-Fe 3+ ] possesses excellent antimicrobial and enhanced MB adsorption. A green in-situ reduction process was used to prepare silver nanoparticles. UV-Vis spectroscopy, TEM, ATR-IR, XRD, SEM-EDS were used to analyze the green produced silver nanoparticles and Ag@HEC-g-P(AA-co-AM)-Fe 3+ . The swelling ratio of Ag@HEC-g-P(AA-co-AM)-Fe 3+ is dependent on AgNPs content and pH. The swelling kinetics fitted with Pseudo-second order. The cumulative release#% of AgNPs was 29.63 ± 1.7%, respectively up to 10 h and its kinetics obey Korsmeyer-Peppas model. The grafting to HEC and incorporation of AgNPs into HEC-g-P(AA-co-AM)-Fe 3+ enhances the thermal stabilities and increases total activation energies from 19,122.2 to 66,287.1 KJ mol. Ag@HEC-g-P(AA-co-AM)-Fe 3+ has powerful antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Micrococcus leutus, Staphyllococus aureus. The maximum adsorption capacity of MB was 133.38 ± 1.25 mg/g at nanocomposite concentration (300 mg/L), pH (9.0), and MB concentration (5 mg/L). To anticipate the adsorption mechanism, Pseudo-first and second-order models, as well as three isotherm models (Langmuir, Freundlich, and Temkin) were used to model adsorption kinetics. The nonlinear Langmuir models and second-order kinetics were the most appropriate., (Copyright © 2021. Published by Elsevier B.V.)

Bacterial infectious diseases are serious health problem which extends to economic and social complications. Moreover, bacterial antibiotic resistance, lack of suitable vaccine or emergence of new mutations is forcing the development of novel antimicrobial agents. The objective of this study is to synthesize and characterize star-like zinc oxide nanoparticles for the application of antibacterial activities in cellulose based hygiene products. ZnO NPs were in situ synthesized via precipitation method on the surface of cellulose fibers. Since bactericidal activity of nanoparticles in part depends on the concentration in the growth medium, various amount of ZnO was incorporated into cellulose matrix ranging from 1 to 3 wt%. Microscopic (TEM, SEM) and spectroscopic (FT-IR, XRD) methods were utilized to investigate the final products. The infrared absorption spectra analysis supported by theoretical finding that during the reaction, ZnO nanoparticles could be bonded with cellulose fibers via hydrogen bonding. The yield of functionalization was determined through thermogravimetric analysis. Collected data proved the successful functionalization of the cellulose fibers with nanoparticles. Static contact angle measurements were carried out showing absorptive character of as prepared fabrics. All the samples were tested for the antibacterial properties and the results were compared to the samples prepared from the pristine cellulose fibers. Moreover, mechanical tests were performed revealing that the addition of only 2 wt% of the nanofiller boosted tensile, tearing and bursting strength by a factor of 1.6, 1.4 and 2.2 in comparison to unfunctionalized paper sample, respectively. Fabricated fabric presenting high hydrophilicity and antibacterial properties have gained increased applications in fabric industry, including hygiene product industry and hence the result of this study would be a welcomed option., (© 2022. The Author(s).)

In the present work, sustainable and green method was used to prepare silver nanoparticles (Ag-NPs), followed with incorporation into tertiary nanocomposite consisted of starch, oxidized cellulose and ethyl cellulose. The prepared tertiary silver-nanocomposite (Ag-NC) was fully characterized via instrumental analysis (UV-vis, FT-IR, XRD, SEM, EDX and TEM) and evaluated for antibacterial, antifungal, and antiviral activities. Ag-NC significantly suppressed growth of tested bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis)  as compared with controls. Antifungal activity revealed that the prepared tertiary Ag-NC has a promising antifungal activity towards unicellular (Candida albicans) and multicellular fungi  ( Aspergillus niger, A. terreus, A. flavus and A. fumigatus). In same line, both Ag-NC and free Ag-NPs have shown a dose-dependent reduction in Vero cell line with maximum non-toxic dose at 6.25 and 12.5 μg/mL, respectively. Both Ag-NPs and Ag-NC exhibited antiviral effects against Herpes simplex virus, Adenovirus and Coxsackie B virus in a dose-dependent manner. Combined treatment of Ag-NPs incorporated into tertiary nanocomposite based on starch, oxidized cellulose and ethyl cellulose opens new possibilities to be more efficient nanomaterials for preventing microbial growth. In conclusion, the prepared tertiary Ag-NC has a promising antibacterial, antifungal as well as antiviral activities., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

The cumulative toxicity of AgNPs has limited their application in food packaging. As such, the quest for AgNPs should focus on controlling their release to reduce the cumulative toxicity. Here, two kinds of green hydrothermal carbonized methods were used to treat sulfhydryl-modified chitosan to obtain two kinds of carbon spheres/AgNPs (Glutinous rice sesameballs-like AgNPs-SMCS and dragon fruit-like SMCS-Ag), which exhibited good stability and high immobilization efficiency for AgNPs, and the release of total Ag from AgNPs-SMCS and SMCS-Ag were only about 5.63% and 3.59% after 14 days, respectively. Subsequently, they were added into chitosan separately to prepare chitosan-based films. Two carbon spheres/AgNPs regulated the microstructure of chitosan-based films because of the electrostatic interaction and the micro-nanometer filling behavior, thus further immobilized the AgNPs. Importantly, the films presented good antibacterial activity and excellent safety. These results will provide a theoretical basis for the green and safe design of AgNPs antibacterial agent., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Cellulose has received great attention owing to its distinctive structural features, exciting physico-chemical properties, and varied applications. The combination of cellulose and silver nanoparticles currently allows to fabricate different promising functional nanocomposites with unique properties. The current work offers a wide and accurate overview of the preparation methods of cellulose-silver nanocomposite materials, also providing a punctual discussion of their potential applications in different fields (i.e., wound dressing, high-performance textiles, electronics, catalysis, sensing, antimicrobial filtering, and packaging). In particular, different preparation methods of cellulose/silver nanocomposites based on in situ thermal reduction, blending and dip-coating, or additive manufacturing techniques were thoroughly described. Hence, the correlations among the structure and physico-chemical properties in cellulose/silver nanocomposites were investigated in order to better control the final properties of the nanocomposites and analyze the key points and limitations of the current manufacturing approaches.

Developing a sustainable, efficient and recyclable heterogeneous Fenton-like catalyst is important to wastewater treatment. Herein, well-dispersed MnO 2 and Fe 3 O 4 nanoparticles inlaid in chitosan beads (MnO 2 -Fe 3 O 4 /CH) was firstly fabricated and employed in the degradation of methylene blue (MB). The bead was prepared via a facile one-step method by dropwise addition of chitosan-metal salt solution into alkaline solution. Comparing with monometallic chitosan beads (MnO 2 /CH, Fe 3 O 4 /CH) and naked MnO 2 -Fe 3 O 4 , MnO 2 -Fe 3 O 4 /CH displayed significantly higher activity for MB degradation with the assistance of hydrogen peroxide (H 2 O 2 ), finally removing 96.8% MB under the optimal conditions (50 mg L -1  MB, 4.0 g L -1 catalyst, 30 g L -1 H 2 O 2 , pH = 7, 60 min). Based on a series of characterizations, the large surface area (60.1 m 2  g -1 ), well-developed porosity (0.3 cm 3  g -1 ), and intensified electron transport of MnO 2 -Fe 3 O 4 /CH consequently enhanced the catalytic performance via a synergistic effect. Because the specific porous structure of MnO 2 -Fe 3 O 4 /CH facilitated the adsorption/diffusion of reactants and exposure of active sites. Meanwhile, the electron transfer from Mn 3+ to Fe 3+ accelerated the Fe 3+ /Fe 2+ cycle, which favored the production of dominant reactive species hydroxyl radical for MB degradation. Besides, the magnetic beads could be easily collected from the solution and reused for five times with a negligible leaching., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Packaging is as important as the product itself because it is a crucial marketing and communication tool for business. Oxidized nanocellulose (ONC), extracted from agriculture residues of bagasse raw material using ecofriendly ammonium persulfate hydrolysis method, is used as support/reducing agent for the generation of silver nanoparticles (AgNPs) via photochemical procedure and reinforcing element in paper functionalization. The natural polymer, sodium alginate (SA) is exploited to enhance the binding of the ONC-AgNPs over cellulose fibers. The SA/ONC-AgNPs bio-nanocomposite is incorporated on paper matrix, which represents a more suitable choice respect to other substrates for its renewable, biocompatible, biodegradable, and cost-effective properties. Structural and antimicrobial evaluations show that the papers embedded with the SA/ONC-AgNPs possess good mechanical, thermal, barrier and antibacterial properties., Competing Interests: Declaration of competing interest There is no conflict of interest in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The laccase/TEMPO system was employed to oxidise the C6 primary hydroxyl group on the chitosan (CS) to form a carboxyl group to obtain oxidised chitosan (C-COS). The silver-oxidised chitosan complex(C-COS-Ag) was prepared by reacting C-COS with silver nitrate, then C-COS-Ag and cotton fibres were subjected to a reaction to prepare bacteriostatic fibres. FT-IR and XPS analysis showed that: Ag + and C-COS were combined in these forms: Ag, [Ag(NH 3 ) 2 ] OH, -COOAg, and Ag 2 O. C-COS-Ag was combined with cotton fibres by way of ester bonds. The inhibition zone of bacteriostatic fibres was all greater than 11 mm. After 50 washing tests, the bacteriostatic effect of bacteriostatic fibres remained at above 99 %. The amount of silver ions that had migrated from the bacteriostatic fibre was 3.336 mg/kg., (Copyright © 2021. Published by Elsevier Ltd.)

Cushioning and antibacterial packaging are the requirements of the storage and transportation of fruits and vegetables, which are essential for reducing the irreversible quality loss during the process. Herein, the composite of carboxymethyl nanocellulose, glycerin, and acrylamide derivatives acted as the shell and chitosan/AgNPs were immobilized in the core by using coaxial 3D-printing technology. Thus, the 3D-printed cushioning-antibacterial dual-function packaging aerogel with a shell-core structure (CNGA/C-AgNPs) was obtained. The CNGA/C-AgNPs packaging aerogel had good cushioning and resilience performance, and the average compression resilience rate was more than 90%. Although AgNPs was slowly released, CNGA/C-AgNPs packaging aerogel had an obvious antibacterial effect on E. coli and S. aureus . Moreover, the CNGA/C-AgNPs packaging aerogel was biodegradable. Due to the customization capabilities of 3D-printing technology, the prepared packaging aerogel can be adapted to more application scenarios by accurately designing and regulating the microstructure of aerogels, which provides a new idea for the development of food intelligent packaging.

Bacterial breeding is the main cause of food perishability, which is harmful to human health. Silver nanoparticles (AgNPs) are one of the most widely used antimicrobial agents, but they are easy to release and cause cumulative toxicity. In this work, with corn stalk as green reductant and GO as template, a simple electrostatic self-assembled sandwich-like chitosan (CS) wrapped rGO@AgNPs nanocomposite film (CS/rGO@AgNPs) was synthesized to achieve stabilizing and controlled-release of AgNPs. The results showed that the the CS/rGO@AgNPs film continued releasing AgNPs for up to 14 days, and the final release amount of silver nanoparticles was only about 1.9 %. More importantly, the nanocomposite film showed durable antibacterial effect and good antibacterial activity against E. coli and S. aureus, and they showed no toxicity to cells. Hence, the nanocomposite film has potential application as an effective and safe packaging material to prolong the shelf life of food products., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Hydrogel-based piezoresistive sensors have high practical value in many revolutionary applications, such as intelligent and electronic devices. However, with existing hydrogels, it is very difficult to achieve a combination of good mechanical properties, stable conductivity, and simple/green fabrication method. In this study, hybrid organic-inorganic nanoparticles (lignin-silver hybrid nanoparticles, Lig-Ag NPs) were synthesized by using alkaline lignin as the organic component and silver nanoparticle (Ag NPs) as the inorganic component. Interaction between the lignin and Ag NPs leads to the composite of hybrid nanoparticles that not only decreased the release of Ag NPs but also generated dynamically stable semi-quinone radicals in lignin. After compositing with polyvinyl alcohol (PVA) matrix, Lig-Ag NPs provided strong sacrificial hydrogen bonds and facilitated the delivery of electronic. Benefiting from these structural features and the pore-forming effect of ammonia (from Lig-Ag NPs solution), the PVA/Lig-Ag NPs hydrogel exhibits outstanding compressibility, pressure sensitivity, and stability of signal response. This study provides a green and simple design strategy for piezoresistive pressure sensors based on nanocomposite hydrogel., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Microbial infections are considered common and dangerous for humans among other infections; therefore the synthesis of high efficacy antimicrobial and anti-biofilm composites is continuous to fight microbial resistance. In our study, a new and novel tertiary composite (TC) was synthesized, it composed of TEMPO cellulose (TOC), chitosan, starch, and myco-synthesized Se-NPs. Myco-synthesized Se-NPs and TC were fully characterized using UV, FT-IR, XRD, SEM with EDX, particle distribution, and mapping. The antimicrobial and anti-biofilm properties of selenium nanoparticles (Se-NPs) were effectively established for Pseudomonas aeruginosa and Staphylococcus aureus biofilms. The possible impact of myco-synthesized novel cellulose-based selenium nanoparticles tertiary composite on the biofilm formation of P. aeruginosa, S. aureus, and Candida albicans was evaluated in this study. TC exhibited constant biofilm inhibition against P. aeruginosa, S. aureus, and C. albicans, while the results obtained from cytotoxicity of Se-NPs and TC showed that, alteration occurred in the normal cell line of lung fibroblast cells (Wi-38) was shown as loss of their typical cell shape, granulation, loss of monolayer, shrinking or rounding of Wi-38 cell with an IC 50 value of where 461 and 550 ppm respectively., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Lignin has been considered as a green carrier with excellent biocompatibility for the biomedical applications in drug release, tissue engineering, etc. In this study, silver nanoparticles (AgNPs) incorporated quaternized lignin (QAL) composites (Ag@QAL) were synthesized in-situ with the assistance of the microwave radiation. The positive charged QAL, not only serves as reductive and stabilizing carriers, but also endows with electrostatic effect toward negatively charged Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), resulting in greatly enhanced antibacterial activity. It is worth mentioning that Ag@QAL exhibits the highest antibacterial activity, which causes 3.72 log 10 (>99.9%) and 5.29 log 10 (>99.999%) CFU/ml reduction against E. coli and S. aureus respectively after contacting for only 5 min. Furthermore, due to the strong interaction between Ag@QAL and Ag + /AgNPs, bacteria can be captured and co-precipitated by Ag@QAL fastly in 30 min with almost none silver ions detected in the supernatant, which prevents Ag + leaking with extremely low toxicity to the biological environment. This concept of electrostatic capture effect induced antibacterial activity enhancement and environmentally benign features may provide new insights into the design of highly effective antibacterial agents in a sustainable manner., 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 © 2020 Elsevier Inc. All rights reserved.)

Mimicking the locomotive abilities of living organisms on the microscale, where the downsizing of rigid parts and circuitry presents inherent problems, is a complex feat. In nature, many soft-bodied organisms (inchworm, leech) have evolved simple, yet efficient locomotion strategies in which reciprocal actuation cycles synchronize with spatiotemporal modulation of friction between their bodies and environment. We developed microscopic (∼100 μm) hydrogel crawlers that move in aqueous environment through spatiotemporal modulation of the friction between their bodies and the substrate. Thermo-responsive poly-n-isopropyl acrylamide hydrogels loaded with gold nanoparticles shrink locally and reversibly when heated photothermally with laser light. The out-of-equilibrium collapse and reswelling of the hydrogel is responsible for asymmetric changes in the friction between the actuating section of the crawler and the substrate. This friction hysteresis, together with off-centered irradiation, results in directional motion of the crawler. We developed a model that predicts the order of magnitude of the crawler motion (within 50%) and agrees with the observed experimental trends. Crawler trajectories can be controlled enabling applications of the crawler as micromanipulator that can push small cargo along a surface.

The current work focuses on a cheap and simple preparation of highly conducting chitosan/hydroxyl ethylcellulose/polyaniline loaded with graphene oxide doped by silver nanoparticles (CS/HEC/PAni/GO@Ag) bionanocomposite as a biodegradable and biocompatible hydrogel for energy storage technology. Scanning electron microscopy (SEM) displays the compatibility of chitosan, hydroxyl ethyl cellulose, and polyaniline and a good distribution of GO@Ag-NPs in bionanocomposite hydrogels. X-ray diffraction (XRD) displayed the structure and existence of GO@Ag-NPs in the matrix. The swelling percentage and the antibacterial activities slightly increased with raising the content of GO@Ag-NPs. Also, the presence of both chitosan and cellulose improves the biodegradation of the fabricated bionanocomposites, which is increased by adding GO. Moreover, the incorporation of 5% GO@Ag-NPs in hydrogels enhances dc-conductivity by about 25 times from 3.37 × 10 -3 to 8.53 × 10 -2 S/cm. The fabricated hydrogels are inexpensive, eco-friendly, and have high capacitance and permittivity, and so they can store electrical energy., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest to be disclosed in this work., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In this work, sodium lignosulfonate (SL) was introduced in the hydrothermal preparation of phenol-formaldehyde (PF) resin sphere that was subsequently used as a green reducer and support for synthesis of Ag nanoparticles (Ag NPs). The results showed that the addition amount of SL had a remarkable effect on the size of the SL incorporated PF (SLPF) spheres and the smallest particle size was obtained when 20% of SL (based on phenol mass) was added. The addition of SL increased the surface area and negative charge of SLPF spheres, which enhanced the Ag NPs loading amount accordingly. Moreover, SL also prevented Ag NPs from aggregating effectively, resulting in the high-density loading of small size Ag NPs on the SLPF spheres. Therefore, the as-prepared Ag@SLPF composites exhibited significantly enhanced catalytic activities in the 4-nitrophenol reduction than that of SL-free Ag@PF. Besides, the Ag@SLPF catalyst demonstrated superior recyclability owing to strong anchoring between the Ag NPs and the support. Consequently, the work demonstrates the incorporation of SL enables the green formation of high-density and tunable Ag NPs on the SLPF support and then endows the composite catalyst with enhanced catalytic performance, which presents a promising value-added application of lignosulfonate for functional catalyst preparation., (Copyright © 2020 Elsevier B.V. All rights reserved.)