Addition Of AgNPs Research Articles

Improving beta phase of spin coated PVDF thin films by doping with silver nanoparticles

This research deals with the effect of process parameters of spin coating such as spinning speed, weight composition of silver nanoparticles (AgNP), and annealing duration on the phase change of polyvinylidene fluoride (PVDF) thin films. FTIR spectroscopy along with XRD confirmed the transformation of α to β-phase in the PVDF thin films. The spin coated films exhibited higher β-fraction than that of the pristine PVDF. The β-fraction in the thin films was mainly influenced by the addition of AgNP. The DSC results showed decrease in crystallinity from 63.74 to 53.21% with increase in spinning speed from 1000 to 3000 rpm due to the over-stretching of crystalline lamellae.

Preparation and thermoelectric properties of InGaSb/Ag-nanoparticles

Silver nanoparticles (Ag-NPs) were added to crystalline In0.5Ga0.5Sb alloy prepared by direct-melting synthesis at 1123 K. XRD, SEM, TEM and HRTEM analysis were used to study the crystal structure and morphology of the synthetized In0.5Ga0.5Sb/Agx samples (x = 0,0 0.05, 0.10, 0.15, 0.20, 0.25 wt%). Perfect crystalline single phase of InSb structure was observed for all samples. Investigations of the electrical conductivity were performed in the temperature range 273 K–473 K by the standard four probe method. A differential method using a laboratory made system was used to measure the Seebeck coefficient, over the temperature range 273 K–473 K. Typical semiconductor behavior of the prepared composites was observed over the whole temperature range. Low electrical conductivities were recorded for all samples with a notable increase with elevating temperature. The highest conductivity value was recorded for the parent In0.5Ga0.5Sb alloy, recorded at 70.85 (Ω m)−1 at 473 K, A maximum absolute value of the Seebeck coefficient |S| was recorded for the most Ag-doped alloy observed at room temperature at 366.6 μVK−1. One of the interesting findings of the current study is that the power factor (PF) of the doped samples is higher than that of the undoped alloys at higher temperatures. The maximum power factor was estimated at 2.3 μWm−1 K−2 for the parent sample at 273 K. Addition of Ag-NPs has improved the thermoelectric power factor due to the corresponding enhancement in the Seebeck coefficient of the studied materials. Such enhancement is attributed to the increment of the grain boundaries and the scattering of the carriers. Low thermal conductivity was revealed for the studied composites.

Silver nanoparticles and arbuscular mycorrhizal fungi influence Trifolium repen root-associated AMF community structure and its co-occurrence pattern

Arbuscular mycorrhizal fungi (AMF) can form symbioses with most plants in terrestrial environments. In this study, we aimed to investigate root-associated AMF community of white clover in response to AMF inoculation and AgNPs addition in the multi-contaminated soil. Results demonstrated that mycorrhizal colonization was significantly increased by AMF inocultion in the 50 mg/kg AgNPs treatment. Compared with non-AMF inocultion group, AMF inoculation group exhibited higher shoot dry mass. In plants without AMF, root dry mass markedly declined when AgNPs addition level exceed 2000 mg/kg. The relative abundance of Glomus was above 70% both in rhizosphere and endosphere. The endosphere Glomus abundance was higher than rhizosphere in all groups. AMF inoculation and AgNPs addition did not influence AMF diversity in rhizosphere and endosphere. Shannon, simpson, chao and ace index in rhizosphere was higher than in endosphere. AMF community structures in endosphere were significantly affected by AMF inoculation and AgNPs additions. Soil Ca, Mg, Mn, P, Al, Mo, As, NH4+-N and pH levels had significant correlations with AMF community in rhizosphere and endosphere. In rhizosphere and endosphere, AgNPs addition (≥100 mg/kg) resulted in more complex networks and AMF inoculation decreased network complexity. We concluded that AgNPs and AMF could influence Trifolium repen root-associated AMF community structure only in endosphere, and co-occurrence networks in rhizosphere and endosphere, but have no effect on alpha diversity.

Fabrication of antimicrobial colorimetric pad for meat packaging based on polyvinyl alcohol aerogel with the incorporation of anthocyanins and silver nanoparticles

AbstractA novel colorimetric pad with porous structure, good antimicrobial activity, and pH‐sensitivity has been developed based on polyvinyl alcohol (PVA), paper fibre, silver nanoparticles (AgNPs) and purple sweet potato anthocyanins (PSPA), aiming for the preservation and freshness indication of fresh meat. The effects of AgNPs content on the structure, physical properties and colour‐changing behaviour in response to pH of the pad were investigated. The results showed that AgNPs physically interacted with polymer matrix and improved the uniformity of the internal pore structure of the pad. The antibacterial capability, DPPH radical scavenging activity and surface hydrophobicity of the pad increased significantly with increasing AgNPs content. However, the pH sensitivity of the pad was maintained with the addition of AgNPs, and the colour change of pad A‐9 with pH was the most distinguishable when AgNPs content was the highest. When pad A‐6 was used in the packaging of minced pork, compared to pad A‐0 without the addition of AgNPs, it showed more significant effects in inhibiting microbial growth, reducing the production of volatile nitrogen compounds, improving the sensory quality of meat (p < 0.05), thereby extending the shelf life from 72 h to 120 h at 4°C. Moreover, A‐6 displayed a visible colour change in response to the spoilage of minced pork in real time. Therefore, the developed pad with dual functions had great potential to be applied as a novel active and intelligent packaging for fresh meat, which would contribute towards reducing food waste and ensuring food safety.

Antibacterial 3D-Printed Silver Nanoparticle/Poly Lactic-Co-Glycolic Acid (PLGA) Scaffolds for Bone Tissue Engineering.

Infectious bone defects present a major challenge in the clinical setting currently. In order to address this issue, it is imperative to explore the development of bone tissue engineering scaffolds that are equipped with both antibacterial and bone regenerative capabilities. In this study, we fabricated antibacterial scaffolds using a silver nanoparticle/poly lactic-co-glycolic acid (AgNP/PLGA) material via a direct ink writing (DIW) 3D printing technique. The scaffolds' microstructure, mechanical properties, and biological attributes were rigorously assessed to determine their fitness for repairing bone defects. The surface pores of the AgNPs/PLGA scaffolds were uniform, and the AgNPs were evenly distributed within the scaffolds, as confirmed via scanning electron microscopy (SEM). Tensile testing confirmed that the addition of AgNPs enhanced the mechanical strength of the scaffolds. The release curves of the silver ions confirmed that the AgNPs/PLGA scaffolds released them continuously after an initial burst. The growth of hydroxyapatite (HAP) was characterized via SEM and X-ray diffraction (XRD). The results showed that HAP was deposited on the scaffolds, and also confirmed that the scaffolds had mixed with the AgNPs. All scaffolds containing AgNPs exhibited antibacterial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). A cytotoxicity assay using mouse embryo osteoblast precursor cells (MC3T3-E1) showed that the scaffolds had excellent biocompatibility and could be used for repairing bone tissue. The study shows that the AgNPs/PLGA scaffolds have exceptional mechanical properties and biocompatibility, effectively inhibiting the growth of S. aureus and E. coli. These results demonstrate the potential application of 3D-printed AgNPs/PLGA scaffolds in bone tissue engineering.

Optimization of 3D Printing Parameters of Polylactic-Co-Glycolic Acid-Based Biodegradable Antibacterial Materials Using Fused Deposition Modeling.

A high incidence of ureteral diseases was needed to find better treatments such as implanting ureteral stents. The existing ureteral stents produced a series of complications such as bacterial infection and biofilm after implantation. The fused deposition modeling (FDM) of 3D printing biodegradable antibacterial ureteral stents had gradually become the trend of clinical treatment. But it was necessary to optimize the FDM 3D printing parameters of biodegradable bacteriostatic materials to improve the precision and performance of manufacturing. In this study, polylactic-co-glycolic acid (PLGA), polycaprolactone (PCL), and nanosilver (AgNP) were mixed by the physical blending method, and the 3D printing parameters and properties were studied. The relationship between printing parameters and printing errors was obtained by single-factor variable method and linear fitting. The performance of 3D printing samples was obtained through infrared spectrum detection, molecular weight detection, and mechanical testing. The printing temperature and the printing pressure were proportional to the printing error, and the printing speed was inversely proportional to the printing error. The 3D printing has little effect on the functional groups and molecular weights of biodegradable antibacterial materials. The addition of AgNP increases the compressive strength and breaking strength by 8.332% and 37.726%, which provided ideas for regulating the mechanical properties. The parameter range of biodegradable bacteriostatic materials for thermal melting 3D printing was precisely established by optimizing the parameters of printing temperature, printing pressure, and printing speed, which would be further applied to the advanced manufacturing of biodegradable implant interventional medical devices.

Effect of silver nanoparticles on structural, thermal, electrical, and mechanical properties of poly(vinyl alcohol) polymer nanocomposites

AbstractThis paper presents the in‐situ chemical synthesis of silver nanoparticles (AgNPs) with glycerol embedded in poly(vinyl alcohol) (PVA) to synthesize (PVA/AgNPs) polymer nanocomposites with different volume percentages of AgNPs (2, 4, and 6) %v/v. X‐ray diffractometer shows the (200) plane of AgNPs, which appeared at 44.82° in PVA/(2, 4, and 6) %v/v AgNPs films. However, the (111), (220), and (311) planes at 2θ (37.55°, 65.08°, and 77.45°) respectively appeared in PVA with 6%v/v AgNPs only. Fourier transform infrared spectroscopy spectrum of AgNPs shows a COC peak at 1273 cm−1 which is attributed to the stronger affinity of AgNPs on the COC bonds in the PVA matrix. The scanning electron microscope confirmed that all nanoparticles are open‐spherical or near‐spherical in shape. Differential scanning calorimetry shows the decrease in glass transition and melting temperature of pure PVA from 64.62° and 185.54° to 53.09° and 182.35° after the incorporation of AgNPs. Thermogravimetric analysis shows the reduction of thermal stability of PVA/AgNPs films when compared to pure PVA. The electrical conductivity of PVA/AgNPs films increased with the addition of AgNPs. From Mechanical studies, the values of Young's modulus, yield strength, and ultimate tensile strength decreased with increasing AgNPs volume percentage.

α-NiO/Ni(OH)2/AgNP/F-Graphene Composite for Energy Storage Application.

The α-NiO/Ni(OH)2/AgNP/F-graphene composite, which is silver nanoparticles preanchored on the surface of fluorinated graphene (AgNP/FG) and then added to α-NiO/Ni(OH)2, is investigated as a potential battery material. The addition of AgNP/FG endows the electrochemical redox reaction of α-NiO/Ni(OH)2 with a synergistic effect, resulting in enhanced Faradaic efficiency with the redox reactions of silver accompanied by the OER and the ORR. It resulted in enhanced specific capacitance (F g-1) and capacity (mA h g-1). The specific capacitance of α-NiO/Ni(OH)2 increased from 148 to 356 F g-1 with the addition of AgNP(20)/FG, while it increased to 226 F g-1 with the addition of AgNPs alone without F-graphene. The specific capacitance of α-NiO/Ni(OH)2/AgNP(20)/FG further increased up to 1153 F g-1 with a change in the voltage scan rate from 20 to 5 mV/s and the Nafion-free α-NiO/Ni(OH)2/AgNP(20)/FG composite. In a similar trend, the specific capacity of α-NiO/Ni(OH)2 increased from 266 to 545 mA h g-1 by the addition of AgNP(20)/FG. The performance of hybrid Zn-Ni/Ag/air electrochemical reactions by α-NiO/Ni(OH)2/AgNP(200)/FG and Zn-coupled electrodes indicates a potential for a secondary battery. It results in a specific capacity of 1200 mA h g-1 and a specific energy of 660 W h kg-1, which is divided into Zn-Ni reactions of ∼95 W h kg-1 and Zn-Ag/air reactions of ∼420 W h kg-1, while undergoing a Zn-air reaction of ∼145 W h kg-1.

Investigating the Effect of Silver Nanoparticles on the Fluorescence Intensity of Bambuterol and its Active Metabolite Terbutaline Using FRET

Silver nanoparticles (AgNPs) were found to significantly quench the fluorescence of bambuterol hydrochloride (BAM) and its active metabolite terbutaline sulfate (TER). The intrinsic fluorescence intensity of each of BAM (at 264/292 nm) and TER (at 276/306 nm) decreased by the gradual addition of AgNPs. Quenching of the steady state fluorescence of BAM and TER probably resulted from the energy transfer to the photo-excited state of AgNPs. The estimated Stern–Volmer quenching constant at several temperature settings proved that the quenching mechanism of the two drugs was dynamic quenching in case of BAM while it was static quenching in case of TER. The number of binding sites, binding constants, and corresponding thermodynamic parameters depending on the interaction system were estimated at 293, 313, and 333 °K and the results obtained were interpreted.

Physicochemical characteristics of Pangasius sp. skin-gelatin-based-edible film enriched with silver nanoparticles

Background: Edible films intended for food packaging have been produced from hydrocolloids, lipids, resins, and composites, including gelatin. Gelatin is known to have a good filming ability and has been suggested as an alternative to non-biodegradable plastics. Naturally active compounds incorporated into film packaging may not only protect the food product from oxidation and microbial contamination, but they may also alter the physicochemical properties of the film. Silver nanoparticles have been used in food packaging as active agents due to their antibacterial and antifungal properties. The addition may affect the characteristics of the packaging. Therefore, this study aims to determine the effect of the addition of silver nanoparticles on the physicochemical characteristics of edible film from Pangasius sp. skin gelatin Methods: Mangrove extract of Bruguiera gymnorrhiza was used to synthesize silver into nanoparticle size. In this study, silver nanoparticles (AgNPs) with different concentrations (0, 2, 4 and 8%) were added into gelatin-based edible film. The edible films produced were observed for their physicochemical characteristics, including thickness, tensile strength, elongation, water vapour transmission, moisture content, pH, and colour. Results: AgNPs affected the colour of the fish-gelatin-based edible film, as an increased concentration of AgNPs resulted in a darker film. Nevertheless, the addition of AgNPs showed no significant effect on the thickness (145–216 µm), tensile strength (14.58–19.72 MPa), elongation (21.86–54.19%), water vapour transmission (30. 91–42.55 g/m2/day), moisture content (9.57–11.16%) or pH (5.92–6.01) of the fish-gelatin-based edible film. Conclusions: The addition of AgNPs has no significant effect on gelatin-based edible film physicochemical properties except colour. Therefore, the incorporated edible film has the potential to be developed further.

In-Depth Insight into the Ag/CNQDs/g-C3N4 Photocatalytic Degradation of Typical Antibiotics: Influence Factor, Mechanism and Toxicity Evaluation of Intermediates.

In this paper, the photocatalytic degradation efficiency of typical antibiotics (norfloxacin (NOR), sulfamethoxazole (SMX) and tetracycline hydrochloride (TCH)) by Ag/CNQDs/g-C3N4 under visible light irradiation was studied. Various strategies were applied to characterize the morphology, structure and photochemical properties of the Ag/CNQDs/g-C3N4 composites. The superior photocatalytic activity of Ag/CNQDs/g-C3N4 was attributed to the wide light response range and the enhancement of interfacial charge transfer. At the same time, the effect of the influence factors (pH, Humic acid (HA) and coexisting ions) on the antibiotics degradation were also investigated. Furthermore, the electron spin resonance (ESR) technology, free radical quenching experiments, LC/MS and DFT theoretical calculations were applied to predict and identify the active groups and intermediates during the photocatalytic degradation process. In addition, Ag/CNQDs/g-C3N4 exhibited the obvious antibacterial effect to Escherichia coli due to the addition of Ag NPs. This study develops a new way for the removal of emerging antibiotic pollution from wastewaters.

Preparation, Structure, and Properties of PVA-AgNPs Nanocomposites.

The aim of the work was to prepare a polymer matrix composite doped by silver nanoparticles and analyze the influence of silver nanoparticles (AgNPs) on polymers' optical and toxic properties. Two different colloids of AgNPs were prepared by chemical reduction. The first colloid, a blue one, contains stable triangular nanoparticles (the mean size of the nanoparticles was ~75 nm). UV-vis spectrophotometry showed that the second colloid, a yellow colloid, was very unstable. Originally formed spherical particles (~11 nm in diameter) after 25 days changed into a mix of differently shaped nanoparticles (irregular, triangular, rod-like, spherical, decahedrons, etc.), and the dichroic effect was observed. Pre-prepared AgNPs were added into the PVA (poly(vinyl alcohol)) polymer matrix and PVA-AgNPs composites (poly(vinyl alcohol) doped by Ag nanoparticles) were prepared. PVA-AgNPs thin layers (by a spin-coating technique) and fibers (by electrospinning and dip-coating techniques) were prepared. TEM and SEM techniques were used to analyze the prepared composites. It was found that the addition of AgNPs caused a change in the optical and antibiofilm properties of the non-toxic and colorless polymer. The PVA-AgNPs composites not only showed a change in color but a dichroic effect was also observed on the thin layer, and a good antibiofilm effect was also observed.

Healable supramolecular micelle/nano-encapsulated metal composite phase change material for thermal energy storage.

Phase change materials (PCMs) have emerged as promising materials for latent heat storage due to their characteristic solid-liquid phase transition behavior during the melting and cooling process. Among them, organic phase change materials are commonly used in latent heat storage. Herein, new phase change self-assembled micelles (PCSM) demonstrated thermal-based phase transition properties. Silver nanoparticles were employed as an additive to improve the thermal properties of the shape-stabilized composite PCSM. The surface morphology and microstructure, general thermal properties and heat adsorption and release behaviors of the samples were characterized with the aid of TEM, SEM, OM, DSC, TGA and DLS techniques. The DSC curve showed that the latent heat adsorption and temperature, heat capacity and thermal reliability of the composite PCSM improved upon the addition of Ag NPs. The TGA curves demonstrated that the presence of Ag NPs increased the onset decomposition temperature and the peak weight loss temperature. PCSM demonstrated low thermal conductivity, whereas the composite PCSM showed better thermal conductivity. This study provides new insight into the promising preparation of healable composite PCMs and their application in thermal energy storage.

The fabrication and evaluation of silver nanoparticle-based keratin scaffolds.

The biotoxicity caused by focus releasing of Ag, which associated with the Ag loading mode, is a problematic issue that need to be solved for practical utilization of the keratin based wound dressing. In this study, keratin/AgNPs blend scaffolds (Ker/Ag) and keratin scaffolds with AgNPs attached on the scaffold's wall surface (Ag@Ker) were prepared. Structure and physical properties of the scaffolds were tested and investigated. In comparison to the Ag@Ker scaffolds, the Ker/Ag scaffolds with uniform dispersion of AgNPs have larger tensile strength and slower degradation rate. Both kind of scaffolds present excellent antibacterial property with 10μg mL-1 AgNPs addition, while the Ker/Ag displayed a linear Ag releasing ratio in the first 5-7days, which is beneficial for obtaining a continuous antibacterial property and avoiding the biotoxicity caused by focus release of Ag. Correspondingly, cytotoxicity assay further reveals that the continuously slow release of Ag of the Ker/Ag scaffolds accelerated the proliferation of cell. Infectious animal models and histological studies showed that the Ker/Ag scaffolds can effectively inhibit the inflammatory response and accelerate epithelialization. Thus, it can be concluded that the Ker/Ag scaffolds with uniform dispersion of AgNPs are more attractive as wound repair materials.

PVA/Chitosan Thin Films Containing Silver Nanoparticles and Ibuprofen for the Treatment of Periodontal Disease.

Local delivery of drugs or antimicrobial agents is a suitable approach in the management of periodontitis when the infection is localized deep in the pockets and does not adequately respond to mechanical debridement and/or systemic antibiotic treatment. In this context, the objective of this study was to prepare new biocomposite films with antimicrobial, anti-inflammatory, and good mechanical properties to be applied in periodontal pockets. The composite film is eco-friendly synthesized from poly(vinyl alcohol) (PVA) cross-linked with oxidized chitosan (OxCS). Silver nanoparticles (AgNps) were inserted during film synthesis by adding freshly chitosan-capped AgNps colloidal solution to the polymer mixture; the addition of AgNps up to 1.44 wt.% improves the physico-chemical properties of the film. The characterization of the films was performed by FT-IR, atomic mass spectrometry, X-ray spectroscopy, and SEM. The films displayed a high swelling ratio (162%), suitable strength (1.46 MPa), and excellent mucoadhesive properties (0.6 N). Then, ibuprofen (IBF) was incorporated within the best film formulation, and the IBF-loaded PVA/OxCS-Ag films could deliver the drug in a sustained manner up to 72 h. The biocomposite films have good antimicrobial properties against representative pathogens for oral cavities. Moreover, the films are biocompatible, as demonstrated by in vitro tests on HDFa cell lines.

Synthesis and Evaluation of a Silver Nanoparticle/Polyurethane Composite That Exhibits Antiviral Activity against SARS-CoV-2.

In this proof-of-concept study, we aim to produce a polyurethane (PU)-based composite that can reduce the amount of viable SARS-CoV-2 virus in contact with the surface of the polymeric film without further interventions such as manual cleaning. Current protocols for maintaining the hygiene of commonly used touchpoints (door handles, light switches, shop counters) typically rely on repeated washing with antimicrobial products. Since the start of the SARS-CoV-2 pandemic, frequent and costly surface sanitization by workers has become standard procedure in many public areas. Therefore, materials that can be retrofitted to touchpoints, yet inhibit pathogen growth for extended time periods are an important target. Herein, we design and synthesise the PU using a one-pot synthetic procedure on a multigram scale from commercial starting materials. The PU forms a robust composite thin film when loaded with 10 wt% silver nanoparticles (AgNPs). The addition of AgNPs increases the ultimate tensile strength, modules of toughness and modulus of elasticity at the cost of a reduced elongation at break when compared to the pristine PU. Comparative biological testing was carried out by the addition of pseudotyped virus (PV) bearing the SARS-CoV-2 beta (B.1.351) VOC spike protein onto the film surfaces of either the pristine PU or the PU nanocomposite. After 24 h without further human intervention the nanocomposite reduced the amount of viable virus by 67% (p = 0.0012) compared to the pristine PU treated under the same conditions. The significance of this reduction in viable virus load caused by our nanocomposite is that PUs form the basis of many commercial paints and coatings. Therefore, we envisage that this work will provide the basis for further progress towards producing a retrofittable surface that can be applied to a wide variety of common touchpoints.

Synthesis of silver nanoparticles from microalgae for potential photocatalytic dye removal

Silver nanoparticles (AgNPs) with excellent optical and electronic properties is gaining significant attention by researchers for wastewater treatment. In recent years, the production of AgNPs has shifted towards green synthesis approach by using bio-reducing agent (e.g. plant extract). In this study, live cells Chlorella vulgaris were used as the bio-reducing agent to produce AgNPs from precursor (silver nitrate (AgNO3) solution). Two process parameters were investigated, namely incubation time and pH. The results affirmed that the optimum synthesis condition of AgNPs was at 24 hr incubation time and pH 8.4 in the mixture of live cells microalgae and 3 mM AgNO3 (3:1 v/v). The synthesized AgNPs showed Localized Surface Plasmon Resonance (LSPR) peak at 412.5 nm with absorption maxima of 0.81 a.u. as indicated using UV-Vis spectrophotometer. The synthesized AgNPs had shown 80.7% of photocatalytic dye degradation in 5 mg/L MB solution and 32.1% in 25 mg/L MB solution within 9 hr of incubation time. The dye removal rate with the addition of AgNPs was 1.2 times faster in 5 mg/L MB solution and was 3.5 times faster in 25 mg/L MB solution as compared to control set.

Silver Nanoparticles (Ag NPs) Boost Mitigation Powers of Chenopodium Quinoa (Q6 Line) Grown under In Vitro Salt-Stressing Conditions

Quinoa (Chenopodium quinoa) is of great economic importance and constitutes one of the model plants for salinity and drought tolerance in the Mediterranean climate. This study aimed to study the physiological responses of Q6 (a quinoa line developed by International Center for Bio-saline Agriculture (ICBA) in cooperation with the National Center for Agricultural Research (NARC), Jordan) grown under in vitro salt-stressing conditions (MS Media plus either 0, 25, 50, 75, 100, 150, or 200 mM of NaCl) and to determine the highest salt level that Q6 plantlets can tolerate. After this, different levels of chemically synthesized silver nanoparticles (Ag NPs) (25, 50, and 75 mg/L) were added to the growth MS media to examine if they can boost the mitigation powers of Q6 plantlets against the highest salt level that the Q6 plantlets could tolerate. Data showed that all tested growth parameters were negatively affected by adding NaCl to the media at all levels. Shoot length, proliferation, and fresh and dry weights declined to reach minimum values at 200 mM NaCl when compared to the other NaCl levels. Similarly, chlorophyll, protein, and ion content were negatively affected when exposed to NaCl at all levels, while proline increased significantly with increasing NaCl in the growth media. The addition of Ag NPs resulted in improving the mitigation powers of Q6 plantlets, especially when 75 mg/L Ag NPs were added, as this resulted in a significant improvement in microshoot growth under 200 mM NaCl when compared to the control. Adding 75 mg/L of Ag NPs to 200 mM NaCl improved shoot growth (3.56 cm) when compared to (1.04 cm) obtained plantlets that were grown in 200 mM NaCl alone. Further, other growth parameters were almost doubled by adding 75 mg/L of Ag NPs to 200 mM NaCl when compared to 200 mM NaCl alone. Additionally, adding Ag NPs (especially at the 75 mg/L level) to the media improved total chlorophyll, protein, and ion content while also reducing proline when compared to the control, which indicated an improvement in microshoot tolerance to salt-stressing conditions. These results indicate that adding specific concentrations of Ag NPs improves the growth performance and stress tolerance of Q6 grown under salt-stressing conditions.

How to Get More Silver? Culture Media Adjustment Targeting Surge of Silver Nanoparticle Penetration in Apricot Tissue during in Vitro Micropropagation

The use of silver nanoparticles (AgNPs) is increasing nowadays due to their applications against phytopathogens. Temporary Immersion Systems (TIS) allow the micropropagation of plants in liquid media. This work aims to develop an effective protocol for apricot micropropagation in TIS and to study the necessary conditions to introduce AgNPs in apricot plants, as well as the effect of its application on proliferation-related parameters. AgNPs were introduced in different media at a concentration of 100 mg L−1 to test the incorporation of silver to plant tissues. Silver content analysis was made by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The effect of initial shoot density and the addition of AgNPs on micropropagation were evaluated after four weeks in culture on TIS. Productivity, proliferation, shoot-length and leave surface were measured. The better micropropagation rate was obtained with 40 initial shoots, 2 min of immersion every 6 h and 3 min of aeration every 3 h. To introduce AgNPs in apricot plants it is necessary to culture them in liquid media without chloride in its composition. These results will contribute to the development of an in vitro protocol for virus inhibition by AgNPs application. This depends on the introduction of Ag nanoparticles within the plant tissues, and this is not possible if AgNPs after interaction with Cl- ions precipitate as silver chloride salts.

Effects of ecotoxicity of penoxsulam single and co-exposure with AgNPs on Eisenia fetida

Penoxsulam (PNX) and silver nanoparticles (AgNPs) are likely to coexist in soils due to continuous use. However, the ecotoxicity of PNX in earthworms and the effect of AgNPs on PNX toxicity are unknown. Therefore, the toxicity of PNX (0.05, 0.5, and 2.5 mg/kg) single and co-exposure with AgNPs (10 mg/kg) after 28 and 56 days on Eisenia fetida (E. fetida) was investigated from biochemical, genetic, histopathological, and transcriptomic aspects. The results showed that the low concentration of PNX (0.05PNX) had almost no effect on the biochemical level of E. fetida. However, the addition of AgNPs resulted in 0.05PNX causing E. fetida to produce excessive reactive oxygen species, and the activity of antioxidant and detoxification enzymes were interfered, resulting in lipid peroxidation and DNA damage. From the genetic level, even the lowest concentration of PNX can significantly interfere with the expression of functional genes, thus inducing oxidative stress and apoptosis and inhibited reproductive behavior in E. fetida. The integrated biomarker response results at the biochemical and genetic levels showed that the comprehensive toxicity of PNX and PNX + AgNPs on E. fetida was PNX dose-dependent. And the toxicity of all co-exposure groups was greater than that of the PNX only exposure groups. Furthermore, the addition of AgNPs significantly increased the damage of PNX on E. fetida intestinal tissue. Meanwhile, transcriptomic analysis showed that PNX + AgNPs had a greater effect on E. fetida than PNX single, and multiple pathways related to oxidative stress, inflammation, and cellular process regulation were disturbed. These results provide a basis for comprehensive evaluation of the ecotoxicity of PNX and confirm that the AgNPs does increase the ecotoxicity of PNX in soil environment.