Increasing Silver Content Research Articles

Impact of plasmonic silver on the perovskite Bi9Ti6FeO27: Removal of tetracycline and antimicrobial activity

The synthesis, characterization, photocatalytic, and antibacterial analysis of plasmonic Ag- loaded Bi9Ti6FeO27 at various concentrations of Ag are presented in this study. The synthesis of Ag/Bi9Ti6FeO27 is based on the impregnation of different weight percentages of Ag (20, 50, and 80) on Bi9Ti6FeO27. The XRD and HRTEM result shows that the perovskite Bi9Ti6FeO27 maintained orthorhombic crystallinity having space group Pnm (No.62). Upon addition of Ag, do not disturb the crystallinity of Bi9Ti6FeO27. XPS analysis displays the valence states and surface chemical composition of the as-prepared Ag/Bi9Ti6FeO27. All the composites exhibit good UV–visible absorbance in the range of 200–800 nm, and the band-gap energy gradually decreases from 3.30 eV to 2.73 eV with an increase in silver content. The photocatalytic degradation of 40 ppm tetracycline is examined at 120 min at neutral pH (7). Loading of Ag on Bi9Ti6FeO27 significantly promoted the photocatalytic degradation efficiency of tetracycline (84 %). Furthermore, the antibacterial activity of Ag/Bi9Ti6FeO27 was investigated against “Escherichia coli”, Klebsiella pneumoniae”, and “Acinetobacter baumannii” bacteria. Higher loading of Ag on Bi9Ti6FeO27 exhibited the most potent antibacterial activity by effectively inhibiting the growth of both bacterial strains through reactive oxidative species and the presence of silver nanoparticles. The composite has proved its stability through the five repeated cycles. This work provides an emerging strategy to finely design the nanocomposites and highlight their potential for environmental remediation and healthcare industries.

Biocompatibility and antimicrobial efficacy of silver-doped borosilicate bioactive glass for tissue engineering application

Borate bioactive glasses are an auspicious material for tissue engineering applications due to their enhanced dissolution rate, bioactivity, and capacity to integrate therapeutic ions. In this study, borate-based S49B4 bioactive glass doped with silver at mass fraction of 0.5, 1, and 3 wt% were studied for bioactivity, degradation, antibacterial, and cytocompatibility. Thermogravimetric analysis revealed that the bioactive glasses were thermally stable between 600 and 700 °C. Fourier transform infrared spectroscopy and X-ray diffraction confirmed the successful synthesis of an amorphous phase of the doped borosilicate bioactive glasses and the incorporation of silver ion crystals within the structure, as well as associated contributions from borate and silicate network formers in the borosilicate bioactive glass. Morphological evaluation revealed that the borosilicate bioactive glasses exhibit a uniform and spherical shape across all formulations, with the mean particle size varying from 65 to 76 nm. An in-vitro acellular bioactivity in simulated body fluid medium showed that increasing the silver content increased the degradation rate and pH. Besides, scanning electron microscopy and Energy dispersive X-ray spectroscopy analysis revealed an upsurge in apatite production on the BBGs' surfaces as well as incremental Calcium-Phosphate ratio values of 1.50, 1.65 and 1.70 as the silver content increases. The antibacterial effect was tested against Escherichia coli and Staphylococcus aureus, while cytocompatibility was tested against human gingival epithelial cells. Silver integration at 1 wt percent yielded the most promising outcomes, which were particularly bactericidal at 79.8 % for Escherichia coli and 93.41 % for Staphylococcus aureus. Similarly, its Lactate Dehydrogenase percentage is significantly similar to the negative control employed in the study, indicating its biocompatibility. In contrast, 3 wt% silver exhibited the maximum bactericidal activity while also exhibiting mild cytotoxicity. In summary, our research indicates that elevated silver concentration enhances the bioactivity and antimicrobial characteristics of borosilicate bioactive glasses; nevertheless, a higher silver weight percent in this study also increases the possibility of cytotoxicity. It is therefore essential to carefully regulate the amount of silver doping at lower concentrations in order to maximize antibacterial action and minimize toxicity to human cells. The results presented here contribute to our understanding of the prospective use of silver doped borosilicate bioactive glasses as a possible material for tissue engineering applications.

Investigation of the substitution of mercury by silver in Ag2S-HgS-GeS2 glasses: Macroscopic, electrical and vibrational properties

The evolution of structure and physical properties was investigated in the (Ag2S)x(HgS)50-x(GeS2)50 system. It was found that the density increases with increasing silver sulfide. The DSC data show a non-monotonic change of the glass transition temperature, Tg, from 243 °C (x = 0) to 301 °C (x = 50) with the minimum at 231 °C for x = 10 sample. The dual structure of HgS, which consists of the presence of dimorphic tetrahedral and chain forms of HgS, is found to be responsible for the non-monotonic change of the Tg. An increase in silver content leads to a significant enhancement of ionic conductivity from ∼10−14 S.cm−1 (x = 0) to ∼10−3 S.cm−1 (x = 50). The gradual structural evaluation is evidenced by the disappearance of the main Raman feature at ≈300 cm−1 related to the Hg-S stretching and the emergence of two contributions for silver-rich glasses at ≈370 cm−1 and at ≈400 cm−1.

Beneficial role of Coronatine on the morphological and physiological responses of Cress Plants (Lepidium sativum) exposed to Silver Nanoparticle

BackgroundSilver nanoparticles are widely used in various fields such as industry, medicine, biotechnology, and agriculture. However, the inevitable release of these nanoparticles into the environment poses potential risks to ecosystems and may affect plant productivity. Coronatine is one of the newly identified compounds known for its beneficial influence on enhancing plant resilience against various stress factors. To evaluate the effectiveness of coronatine pretreatment in mitigating the stress induced by silver nanoparticles on cress plants, the present study was carried out.ResultsOur findings indicated a decrease in multiple growth parameters, proline content, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids in cress plants exposed to silver nanoparticle treatment. This decline could be attributed to the oxidative stress induced by the presence of silver nanoparticles in the plants. Conversely, when coronatine treatment was applied, it effectively mitigated the reduction in growth parameters and pigments induced by the silver nanoparticles. Furthermore, we observed an increase in silver content in both the roots and shoot portions, along with elevated levels of malondialdehyde (MDA) content, hydrogen peroxide (H2O2), anthocyanins, glutathione (GSH), and antioxidant enzyme activities in plants exposed to silver nanoparticles. Concurrently, there was a decrease in total phenolic compounds, ascorbate, anthocyanins, and proline content. Pre-treatment of cress seeds with coronatine resulted in increased levels of GSH, total phenolic compounds, and proline content while reducing the silver content in both the root and shoot parts of the plant.ConclusionsCoronatine pre-treatment appeared to enhance both enzymatic and non-enzymatic antioxidant activities, thereby alleviating oxidative stress and improving the response to stress induced by silver nanoparticles.

Comparative study of photocatalysis with bulk and nanosheet graphitic carbon nitrides enhanced with silver

The main goal of this research is to investigate the effectiveness of graphitic carbon nitride (g-C3N4, g-CN) in both bulk and nanosheet forms, which have been surface-modified with silver nanoparticles (Ag NPs), as photocatalysts for the degradation of acid orange 7 (AO7), a model dye. The photodegradation of AO7 dye molecules in water was used to test the potential photocatalytic properties of these powder materials under two different lamps with wavelengths of 368 nm (UV light) and 420 nm (VIS light). To produce Ag NPs (Ag content 0.5, 1.5, and 3 wt%) on the g-CN materials, a new synthesis route based on a wet and low-temperature method was proposed, eliminating the need for reducing agents. The photodegradation activity of the samples increased with increasing silver content, with the best photocatalytic performances achieved for bulk g-CN samples and nanosheet silver-modified samples (with the highest content of 3 wt% Ag) under UV light, i.e., more than 75% and 78%, respectively. The VIS-induced photocatalytic activity of both examined series was higher than that of UV. The highest activities of 92% and 98% were achieved for the 1.5% Ag-modified g-CN bulk and nanosheet materials. This research presents an innovative, affordable, and environmentally friendly chemical approach to synthesizing photocatalysts that can be used for degrading organic pollutants in wastewater treatment.

Viscose fibers decorated with silver nanoparticles via an in-situ green route: UV protection, antioxidant activities, antimicrobial properties, and sensing response

Multifunctional cellulosic fibers are in high demand for use in a variety of applications. Functional cellulosic fibers obtained through green and sustainable approaches are getting special attention because of the need to limit the environmental impact of hazardous chemicals. Herein, a novel facile, efficient, and eco-friendly approach for multifunctional viscose fibers@Ag NPs (VF-Ag) was designed by a rapid, facile, and one-pot biosynthesis green route using guava leaf extract as a reducing and stabilizing agent. UV–Vis, TEM, SEM, EDX, FTIR, and XPS were used to analyze the formation of silver nanoparticles and their subsequent deposition on the surface of viscose fibers. The silver nanoparticles immobilized on the surface of viscose fibers endowed a yellow/brownish color to the fibers as well as improving the dyeing with reactive dye. The VF-Ag samples have multifunctional properties like protective activities against UV radiation and microorganisms, antioxidant activity, and sensor ability toward Hg2+. The results demonstrated that the UPF values of VF-Ag samples ranged from 280 to 355 compared to 103 for VF. The antioxidant activities of VF-Ag ranged from 79 to 85% compared to 9% for VF. VF-Ag samples exhibited excellent antimicrobial activities against Gram-positive and Gram-negative bacteria, very good activities against yeast, and low activities against fungus.VF and VF-Ag were dyed using reactive dye (CI-reactive blue-19) at two color intensities (2.5, and 5%). The results show that the color of VF turned blue, while the color of VF-Ag turned greenish. The color strength of VF-Ag significantly increased with increasing silver content. Furthermore, VF-Ag showed high sensitivity to naked-eye colorimetric sensing for the detection of Hg2+. In straightforward, this innovative approach provides an easy, quick, and low-cost that will open the door for a range of versatile applications for modified viscose fibers in the fields of medical and analytical applications.

Structural Assessment of Silver Conductive Ink using Nanoindentation

Stretchable conductive inks have emerged as a key enabling technology for the development of flexible and wearable electronic devices. Silver nanoparticles are commonly incorporated into these inks to impart electrical conductivity while maintaining stretchability. However, the amount of silver in the ink formulation can significantly influence the structural integrity and mechanical performance of printed conductive inks. This study investigates the impact of different silver contents on the structural assessment of stretchable conductive ink. Three samples of conductive inks, each with a different silver concentration (40%, 60%, and 80%) were produced by combining a PDMS-OH binder, organic solvent, cross-linking agent, catalyst, viscosity controller, additives, and silver nanoparticles. The ink samples with varying silver concentrations are characterized using nanoindentation and field-emission scanning electron microscopy (FESEM). The electrical conductivity of the silver conductive ink was measured with a digital multimeter. Among the three samples, the optimal silver concentration for conductive ink formulation is 60%, which exhibits a hardness of 2.04 MPa and an elastic modulus of 32.9 MPa to balance mechanical elasticity with an electrical conductivity of 1.389x104 S/m. Increasing silver content reduces the ink's flexibility, making it more brittle and less stretchable, but it also boosts its conductivity. The findings provide valuable insights into optimizing the silver content in stretchable conductive inks for achieving robust structural integrity and reliable performance in flexible and stretchable electronics.

Antibacterial activity and biocompatibility of titanium nickelide augments with the addition of silver nanoparticles for bone grafting: an experimental study

BACKGROUND: The relevance of this study was supported by the increasing number of infectious complications of bone augmentation in children and adults. Currently, porous titanium nickelide alloys are among the most preferred materials used in bone plasty. Despite the observable advantages of porous nickelide titanium alloys in terms of biochemical and biomechanical compatibility with the body, research on the antibacterial activity of alloys is ongoing to counter the development of infections at the implant–biological tissue border.
 AIM: To perform an experimental study of the biocompatible antibacterial surface in porous titanium nickelide alloys with the addition of silver nanoparticles.
 MATERIALS AND METHODS: Titanium nickelide alloys with 62% porosity were obtained using the self-propagating high-temperature synthesis method from nickel, titanium, and nanosilver powders at concentrations of 0.2 at.% Ag, 0.5 at.% Ag, and 1.0 at.% Ag, respectively. The experiment was conducted on nine sexually mature female white laboratory rats. They were divided into three groups, with three rats each. All animals were implanted with titanium nickelide along with porous granules of silver additives. The first group was the control, the second received 0.2 at.% silver, and the third received 0.5% silver. The standard method of incubating Staphylococcus epidermidis in liquid broth in the presence of the studied images was used to determine bactericidal activity, followed by seeding on solid media and counting colonies.
 RESULTS: The antibacterial effect of the samples on S. epidermidis gradually increased with increasing silver concentration. The significance of the differences between the experiment and control was confirmed by Student’s criterion p 0.005, whereas the sample without silver nanoparticles and the control do not differ significantly. Thus, these alloys may have bioactive properties because they contain silver nanoparticles. An alloy with a silver concentration of 0.5 at.% Ag showed the best antibacterial activity to S. epidermidis. In the clinical evaluation of the results of the experimental study, purulent inflammatory complications were not observed in all animals at all times. On day 75, the animals underwent computed tomography, which showed good occupancy of the bone defect and absence of a dystrophic effect on the area where the bone and soft tissue are in contact with the material.
 CONCLUSIONS: If the concentration of silver nanoparticles is increased up to 0.5 at%, the antibacterial activity and cytocompatibility of the implant also increase. Clinical experimental evaluation in all groups of animals showed that osteointegration of alloys with 0.5 at.% Ag begins immediately after implantation and is completed 2 weeks earlier than that in the remaining groups.

Substrate Matters: Ionic Silver Alters Lettuce Growth, Nutrient Uptake, and Root Microbiome in a Hydroponics System.

Ionic silver (Ag+) is being investigated as a residual biocide for use in NASA spacecraft potable water systems on future crewed missions. This water will be used to irrigate future spaceflight crop production systems. We have evaluated the impact of three concentrations (31 ppb, 125 ppb, and 500 ppb) of ionic silver biocide solutions on lettuce in an arcillite (calcinated clay particle substrate) and hydroponic (substrate-less) growth setup after 28 days. Lettuce plant growth was reduced in the hydroponic samples treated with 31 ppb silver and severely stunted for samples treated at 125 ppb and 500 ppb silver. No growth defects were observed in arcillite-grown lettuce. Silver was detectable in the hydroponic-grown lettuce leaves at each concentration but was not detected in the arcillite-grown lettuce leaves. Specifically, when 125 ppb silver water was applied to a hydroponics tray, Ag+ was detected at an average amount of 7 μg/g (dry weight) in lettuce leaves. The increase in Ag+ corresponded with a decrease in several essential elements in the lettuce tissue (Ca, K, P, S). In the arcillite growth setup, silver did not impact the plant root zone microbiome in terms of alpha diversity and relative abundance between treatments and control. However, with increasing silver concentration, the alpha diversity increased in lettuce root samples and in the water from the hydroponics tray samples. The genera in the hydroponic root and water samples were similar across the silver concentrations but displayed different relative abundances. This suggests that ionic silver was acting as a selective pressure for the microbes that colonize the hydroponic water. The surviving microbes likely utilized exudates from the stunted plant roots as a carbon source. Analysis of the root-associated microbiomes in response to silver showed enrichment of metagenomic pathways associated with alternate carbon source utilization, fatty-acid synthesis, and the ppGpp (guanosine 3'-diphosphate 5'-diphosphate) stringent response global regulatory system that operates under conditions of environmental stress. Nutrient solutions containing Ag+ in concentrations greater than 31 ppb in hydroponic systems lacking cation-exchange capacity can severely impact crop production due to stunting of plant growth.

Ag-doped NiS nanocubes: Tailoring properties for optimal antibacterial performance

This study explores the synthesis of silver-doped nickel sulfide nano-cubes (Ni1-xAgxS: x= 0.00, 0.04, and 0.08) through a cost-effective hydrothermal process. X-ray diffraction analysis assured the presence of hexagonal NiS nanoparticles with fine crystallinity, with an estimated crystallite size of Ag-doped NiS ranges from 21.19 to 15.69 nm. A reduction in crystallite size was observed while including Ag ions along with enhancement in lattice constants for ‘a’ and ‘b’ from 3.416 Å to 3.424 Å and ‘c’ from 5.280 to 5.286 Å. The scanning electron microscopic images displayed cubic shaped agglomerated particles, that seemed quite suitable for antibacterial activity. The materials exhibit semiconducting behavior, as evidenced by increased direct current electrical conductivity with the rise in temperature. With increased silver content, the direct current electrical conductivity rises, and activation energy decreases from 0.246 to 0.213 eV. Dielectric characteristics, including dielectric constant, dielectric loss, and AC electrical conductivity, show a positive correlation with temperature, and all the aforementioned values elevates with systematic variation in Ag doping. The Agar well-diffusion method evaluates the antibacterial activity of un-doped and Ag-doped NiS nano-cubes against various pathogens, such as Gram-positive bacteria (M. luteus and S. aureus) and Gram-negative bacteria (E. coli and S. enterica), and significant inhibitory zones against all tested microbes, confirming the potential antibacterial efficacy. The Ag-doped NiS exhibited enhanced antibacterial efficiency. This research highlights Ag-doped NiS nano-cubes attributed with multifaceted functionalities, making them promising candidates for particular usage such as targeted drug delivery systems, antibacterial powder, wastewater treatment and pharmaceutical applications.

Cell migration, DNA fragmentation and antibacterial properties of novel silver doped calcium polyphosphate nanoparticles

To combat infections, silver was used extensively in biomedical field but there was a need for a capping agent to eliminate its cytotoxic effects. In this study, polymeric calcium polyphosphate was doped by silver with three concentrations 1, 3 or 5 mol.% and were characterized by TEM, XRD, FTIR, TGA. Moreover, cytotoxicity, antibacterial, cell migration and DNA fragmentation assays were done to assure its safety. The results showed that the increase in silver percentage caused an increase in particle size. XRD showed the silver peaks, which indicated that it is present in its metallic form. The TGA showed that thermal stability was increased by increasing silver content. The antibacterial tests showed that the prepared nanoparticles have an antibacterial activity against tested pathogens. In addition, the cytotoxicity results showed that the samples exhibited non-cytotoxic behavior even with the highest doping concentration (5% Ag-CaPp). The cell migration assay showed that the increase in the silver concentration enhances cell migration up to 3% Ag-CaPp. The DNA fragmentation test revealed that all the prepared nanoparticles caused no fragmentation. From the results we can deduce that 3% Ag-CaPp was the optimum silver doped calcium polyphosphate concentration that could be used safely for medical applications.

Electromagnetic and microwave absorption properties of flexible fabric coatings containing Ag decorated spherical graphene powders with FSS incorporation

Flexible textile microwave absorbing materials own the advantages of flexibility, foldability and cuttability, have become a research hotspot in electromagnetic stealth technology. In this study, a microwave absorbing coating was prepared on a fabric substrate using Ag decorated spherical graphene (SG) as the absorbent. XRD results demonstrated the metallic Ag ion was successfully reduced. TEM photographs showed the silver nanoparticles were stuck to the spherical graphene. The complex permittivity was enhanced after compositing with Ag particles. Along with the increase of silver content from 0 to 20 wt%, the complex permittivity rises from 3.29–0.42j to 6.93–2.22j owing to its higher electric conductivity and stronger relaxation effect. Meanwhile, the flexible coating containing Ag decorated spherical graphene (Ag@SG) also exhibited better microwave absorption performance. The minimum reflection loss (RLmin) for the coating with a thickness of 3.0 mm was −15 dB. And the effectively absorbing broadband (EAB) is located at 9.08–11.52 GHz. In addition, the microwave absorbing performance was greatly enhanced after being combined with periodic frequency selective surface (FSS). The EAB was obtained over the entire X-band frequency range, and the RLmin value achieved −41.72 dB at 10.25 GHz. What's more, the coating owned an EAB in a wide range incident angle of 60°–90°. This work was help to developing high performance flexible fabric coating containing Ag decorated spherical graphene with FSS incorporation.

Chitosan coating silver nanoparticles as a promising feed additive in broilers chicken

The present study aimed to evaluate the potential of chitosan coating silver nanoparticles to enhance the growth performance and immune status of broilers without inducing oxidative stress-related pathological lesions in any organs or leaving residues of silver in the edible parts. Five clusters of Cobb one-day-old chicks (n = 10/group in each replication) were given oral therapy, once a week for 36 days as follows: (1) distilled water, (2, 3) 0.5- and 5 ppm silver nanoparticles (AgNPs), respectively, (4, 5) 0.5- and 5 ppm chitosan/silver nanoconjugates (CS/Ag-NCs), respectively. The results demonstrated a marked elevation in the body weight gain with a decline in the food conversion ratio and marked improvement in feeding and drinking behavior of all nanoparticles treated groups, but higher in CS/Ag-NCs groups than AgNPs groups and control group. In contrast to the 0.5 ppm AgNPs receiving group, the group receiving 5 ppm AgNPs noticed remarkable histological changes in some organs, including the liver, kidneys, spleen, and heart. Moreover, the administration of CS/Ag-NCs at two dosage levels didn’t influence any histological changes. The AgNPs groups’ antibody titers against the ND and AI viruses were almost identical to those of the control group. Otherwise, CS/Ag-NCs groups recorded the highest antibody titers. Additionally, there was a significant increase in silver content in most edible organs of AgNPs groups at a dosage level of 5 ppm. Otherwise, the coating of AgNPs by CSNPs could decrease the aggregation of silver in the biological organs. Thus, we recommend utilizing 0.5 ppm CS/Ag-NCs in broiler farms to promote their growth performance and strengthen their immune defense.

Green synthesis of Ag-Poly (styrene sulfonate) nanoparticles and their application in cotton fabric

This paper presents a method for the controlled reduction of silver chloride (AgCl) by D-(+)-Maltose in the presence of poly(sodium 4-styrenesulfonate) (PSS). PSS, acting as a polyelectrolyte, plays a crucial role in the process by accommodating silver ions (Ag+) through electrostatic interactions during synthesis and stabilizing the resulting silver nanoparticles (AgNPs). UV-Vis spectra revealed distinct absorption bands characteristic of AgNPs, with the Ag-PSS ratio affecting the size and distribution of nanoparticles. Dynamic light scattering (DLS) and zeta potential measurements confirmed the relationship between silver concentration and nanoparticle uniformity. Layer-by-Layer (LbL) deposition of Ag-PSS nanohybrids on cotton fabric surfaces, offering a unique approach for fabric modification. Energy-Dispersive X-ray Spectroscopy (EDS) analysis demonstrated a consistent increase in silver content with an increase in bilayers. Scanning Electron Microscopy (SEM) revealed enhanced fiber roughness, indicating effective nanohybrid deposition. Elemental mapping showcased uniform elemental distribution across the fiber surface, underscoring the precision of the LbL technique. In conclusion, this study presents an effective method for achieving uniform surface modification of cotton fibers through LbL deposition of Ag-PSS nanohybrids.

All wet preparation of Ag-As33S67 thin films by silver ions photodiffusion from silver nitrate solution

Amorphous As33S67 thin films were prepared by spin-coating method from n-butylamine based glass solution as well as by thermal evaporation. Thin films were doped by silver ions from a solution of silver nitrate in dimethylsulfoxide. The influence of illumination on the photodoping kinetics was studied in dependence on the deposition technique and thermal pre-history of solution processed As33S67 thin films. Doped thin films maintained good optical quality, decreased optical bandgap and increased refractive index were observed with increasing silver content. Highly doped thin films remained amorphous. A hypothesis explaining observed significant differences in doping mechanisms between solution processed and thermally evaporated samples was proposed based on structural differences and organic residua content. Described procedure simplifies the silver doping technique and our findings proved, that it is suitable for all wet processes, thus excluding the necessity for vacuum deposition of solid silver film.

Silver substituted cobalt zinc ferrites as magnetic antimicrobials

Silver-substituted cobalt zinc ferrite series, CoxAg0.5-xZn0.5Fe2O4 (x = 0.4, 0.3, 0.2, 0.1), is synthesized using the citrate gel method, wherein ferrite formation is achieved at 600 °C. The low-temperature crystallization results in agglomerated and porous ferrites. In this sample preparation methodology, as the silver content in the series increases, metallic silver deposits at the grain boundaries, and vacancies are created at the octahedral sites. With a further increase in silver content, the magnitude of magnetic properties decreases. Antimicrobial activity increases and further decreases with an increase in silver content. The composition Co0.4Ag0.1Zn0.5Fe2O4 exhibits both magnetic and antimicrobial behaviour. These materials can potentially be beneficial in the manufacture of removable antimicrobial agents for water purification and drug delivery systems.

On-Demand Release of Anti-Infective Silver from a Novel Implant Coating Using High-Energy Focused Shock Waves.

Implant-related infections are a significant concern in orthopedic surgery. A novel anti-infective implant coating made of bioresorbable polymer with silver nitrate was developed. A controlled release of silver ions into the vicinity of the prosthesis can be triggered on-demand by extracorporeal shock waves to effectively combat all clinically relevant microorganisms. Microscopy techniques were used to examine the effects of shock wave application on coated titanium discs. Cytotoxicity was measured using a fibroblast proliferation assay. The anti-infective effect was assessed by monitoring the growth curves of three bacterial strains and by conventional culture. Microscopic analysis confirmed surface disruption of the coatings, with a complete release of silver in the focus area after shock wave application. Spectrometry detected an increase in silver concentration in the surrounding of the discs that surpassed the minimum inhibitory concentration (MIC) for both S. epidermidis RP62A and E. coli ATCC 25922. The released silver demonstrated an anti-infective effect, significantly inhibiting bacterial growth, especially at 6% and 8% silver concentrations. Cytotoxicity testing showed decreasing fibroblast viability with increasing silver concentration in the coating, with 6% silver maintaining viability above 25%. Compared to a commonly used electroplated silver coating on the market, the new coating demonstrated superior antimicrobial efficacy and lower cytotoxicity.

Photocatalytic and bactericidal behaviors of Ag/TiO2 doped biochar through Ball–milling approach

Biochar materials derived from various biomass feedstocks have attracted considerable interest as high-performance sorbents for a wide range of contaminants in wastewater. However, the diligence and preoccupation in developing multifunctional materials with interesting properties has prompted researchers worldwide to consider the functionalization of pure biochar for more beneficial applications. In this study, for the first time, a novel ternary photocatalyst was successfully prepared from date palm rachis biochar (BDPR) and silver-doped titanium dioxide (Ag/TiO2) nanoparticles with different Ag/Ti weight ratios using a simple and environmentally friendly ball milling technique. The structural and physicochemical properties of the resulting photocatalysts were investigated by various characterization methods, namely X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA) and UV-diffuse reflectance spectroscopy (UV-DRS). The photocatalytic property of the photocatalysts was evaluated through the degradation of organic dyes, namely, methylene blue (MB) and Congo red (CR). The results show that the photocatalytic activity was greatly enhanced with increasing silver content compared to the neat and TiO2-doped biochars. Complete removal of methylene blue was achieved after 90 and 75 min for 5 %Ag/TiO2-BDPR and 10 %Ag/TiO2-BDPR, respectively, while it took 150 min for 100% photodegradation of Congo red. This was due to the synergistic effect of biochar, silver and TiO2 in trapping electrons and reducing the recombination of e-/h+ pairs. In addition, the photocatalysts could be regenerated and reused for up to 5 cycles without significant degradation of their properties. Furthermore, both 5% and 10% Ag/TiO2 BDPR photocatalysts exhibited high antibacterial activity against E. coli and S. aureus bacteria due to the combined effect of biochar as a sorbent, reactive oxygen species (ROS) and silver.

A promising hydroxyapatite whisker with long-term and high-efficiency antibacterial performance and its potential application in implant

• The synergistic effect of nano-zinc oxide and silver ions can realize broad-spectrum antibacterial. • The silver ions in the hydroxyapatite whiskers will gradually dissolve as the whiskers degrade, realizing long-term antibacterial effects. Osteomyelitis remains one of the most challenging diseases for orthopedic doctors despite the advancement of therapeutic techniques. Biomaterials with antibacterial activities are beneficial to prevent infection post implantation. The aim of this study was to evaluate the antibacterial effects of three biomaterials including pure- hydroxyapatite (HA), Ag-HA and Ag-HA/ZnO. The prepared materials were analyzed by X-ray diffractometer (XRD), scanning electron microscope (SEM), cell adhesion and long-service antibacterial ability. The results showed that with the increase of silver content, the growth of whiskers was inhibited and the aspect ratio became smaller. Nano-zinc oxide is evenly attached on the surface of the whiskers. Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus) were used for antibacterial tests. The results showed that Ag-HA and Ag-HA/ZnO had good antibacterial ability against E. coli and S. aureus . Thus, the low amount of Ag-HA has a potential of minimizing the risk of bacterial contamination, without compromising the bioactivity, and is expected to display greater biological efficacy in terms of osseointegration. Ag + and ZnO particles have a synergistic effect and can effectively kill most bacteria. At the same time, with the degradation of hydroxyapatite, Ag + is slowly released, which can play a long-term antibacterial effect.

Influence of Ag on microstructure, mechanical properties and tribological properties of as-cast Al-33Zn-2Cu high-zinc aluminum alloy

The effect of Ag on the microstructure, mechanical properties, and tribological properties of Al-33Zn-2Cu alloys was investigated. The results show that the mechanical properties of the high-zinc aluminum alloy increase linearly with increasing silver content. The yield strength, tensile strength and elongation of the Al-33Zn-2Cu-0.6Ag alloy are 370 MPa, 433 MPa and 8.2% respectively. Wear resistance was also significantly improved. As the silver content in the Al-33Zn-2Cu alloy increases, the density of the η' phase in the α matrix increases. The addition of Ag aggravates the discontinuous precipitation of the α + η phase, resulting in the inhibition of the continuous large α + η phase in the alloy and the transformation into small discontinuous precipitation phases. Besides, as the Ag content increases, the lamellar α + η phases formed at the grain boundaries become finer and denser. This study may provide innovative ideas for alloy design of high-zinc aluminum alloys.