Silver Nanopowder Research Articles

Investigation of Ultrasonic Vibration Assisted Powder Mixed Electrical Discharge Machining for Antibacterial Coating on Implant Surfaces

Despite demonstrating a strong antibacterial property, surfaces machined and coated by nano-silver powder mixed electrical discharge machining (PMEDM) are faced with challenges relating to regulation of silver distribution as well as the spattered layer. These are among the main challenges that inhibit PMEDM’s suitability for medical implant applications, if the antibacterial coating is required. This study aims to solve these problems by introducing ultrasonic vibrations while machining Ti-6Al-4V workpiece surfaces using powder mixed electrical discharge machining involving both sinking and milling operations. During machining, the concentration of powder suspended in the dielectric fluid, the vibration amplitude as well as tool electrode size are varied. Results show that ultrasonic vibration has a capability to not only enhance the silver uniformity on the surface, but to also prevent the occurrence of a spattered layer, both of which are significantly affected by the vibration amplitude. Furthermore, for ultrasonic vibration assisted PMEDM, the tool electrode size plays an important role in the re-solidification process of the molten material since it influences the turbulence intensity, the occurrence of cavitation as well as the dielectric fluid’s flow rate in the machining gap.

Novel nontoxic electrochemical method for the detection of cefadroxil in pharmaceutical formulations and biological samples

The current study represented a novel nano-silver amalgam pastes microelectrode (nano-Ag-APME) as a suitable alternative for the assay of cefadroxil contents in pharmaceutical formulations and biological specimen. The proposed electrode prepared in a plastic tip of micropipette tied with the nano-silver amalgam pastes mainly comprise of silver nano-powder and pure mercury (1:9, w/w). The commercial silver nanopowder and nano-silver amalgam paste were characterized using scanning electron microscope–energy dispersive X-ray spectrometer and X-Ray Diffraction (XRD). These analyses depicted that nano-Ag amalgam paste formed Ag-Hg clusters consisting of a crystalline solid. The EDX analysis showed that all the chemical composition of the starting materials (silver nanopowder) consisted of the nano-Ag amalgam paste having Ag and Hg only. The optimization of different characteristics such as voltammetric modes, pH, type of supporting electrolytes, electrolyte volume, stirring rate, accumulation potential, and accumulation time for the determination of cefadroxil by SW-AdSV examined in detailed. The proposed method based on the square-wave stripping voltammetry for the measurement of cefadroxil at pH 4 in Britton–Robinson buffer, manifested a well-defined reduction peak at −0.160 V. The comparative study of SW-AdSV and spectrophotometric methods showed the linear response for CFL at a linear dynamic ranged from 0.033–0.304 and 10–70 µM, respectively. The analytical performance for the quantification of CFL by the SW-AdSV method was significantly good as compared to the spectrophotometric method (p < 0.01). Moreover, it has been indicated that the SW-AdSV is more sensitive and selective for precise routine analysis of CFL than the spectrophotometric method.

Laser Application in Photovoltaics for Surface Texturization of Silicon and Front Electrode Deposition

Abstract The laser technology in the manufacturing of solar cells has become an indispensable element of modern photovoltaic technology. The main reason for taking up such research is because conventional methods used for monocrystalline silicon texturization are ineffective when applied to polycrystalline silicon texturing. This is related to random distribution of grains of different crystalographic orientations on the surface of polycrystalline silicon. Texturing a polycrystalline silicon surface using an Nd:YAG laser makes it possible to increase absorption of the incident solar radiation. The additional technological operation of etching in potassium hydroxide solution introduced into the technology of the photovoltaic cells manufactured from laser-textured wafers allows for improvement in electrical performance compared with cells produced from nontextured wafers. Moreover, this article presents the influence of selective laser sintering of front metallization that was manufactured using paste based on silver nanopowder on contact resistant. The electrodes were formed on monocrystalline silicon solar cells. The microstructures of laser-textured silicon and sintered front metallization were investigated by scanning electron microscope and confocal laser scanning microscope. The reflectance of produced textures was measured by spectrophotometer with an integrating sphere. Current-voltage characteristics of solar cells manufactured from laser-textured polycrystalline silicon wafer were measured under standard AM 1.5 radiation. The contact resistance between the metal and semiconductor was investigated using the transmission line model.

Synthesis and Characterization Structure and Physical Properties [ 50-xTiNi – x Ag] Shape Memory Alloy

In this research, a metal alloy was prepared and its structural and physiological properties were studied. The method of powder technology was used in mixing and mixing powders. The ratio of 1: 1 was mixed with 100 micron granular powder and nickel powder with granular size of 78 microns. The mixture was then reinforced with a nanocrystalline powder with a mixing ratio of 0%, 1%, 3%, 5% and 7%), where the powders were mixed in an effective mechanical mixing method at a rate of 350 rpm and 6 hours continuously. Physical tests (density, hardness, yield strength, young modulus) were performed. The electrical tests were carried out using four sensors (probs) such as resistivity and electrical conductivity, as well as structural tests such as X-ray diffraction and scanning electron microscopy. The results showed a significant improvement in the micro hardness values using Vickers hardness, which resulted in improved yield strength and young modulus respectively. The results of the test showed that the electrical conductivity properties showed a clear reduction in the resistivity values of the alloys supported by the nano-silver powder and an increase in the values of the electrical conductivity compared to the base alloy (nickel-titanium).

Influence of parameters of high-voltage electrospark dispersion of materials on granulometric composition of nanopowders

The influence of parameters of high-voltage electric spark dispersion of materials on the granulometric composition of nanopowders of metals and alloys is considered. The most interesting feature of the developed experimental setup is the presence of an air discharge gap (FV1), which creates an overvoltage on the working discharge gap (FV2). The discharge gaps form a voltage divider when the capacitor (C) is discharged. It was assumed that the voltage divider should have a significant impact on the operation of the experimental setup. Studies have shown that when the air gap (FV1) is much larger than the working gap (FV2), their exact ratios do not affect the size of the resulting nanoparticles. At such ratios of discharge gaps, the voltage divider allows to regulate only the performance of the process of obtaining nanopowders. The resulting silver nanopowders had a spherical shape and a rather narrow size distribution. It is necessary to further study the process of high-voltage spark dispersion of materials with a significant overvoltage of the discharge gap.

Thermal conductivity and sorption performance of nano-silver powder/FAPO-34 composite fin

Desiccant coated aluminum fins are an important part of desiccant coated heat exchangers (DCHEs). The overall performance of DCHE-based systems benefits from improved heat and mass transfer characteristics of desiccant coated aluminum fins. In this paper, a new type of nano-silver powder supported FAPO-34 composite fin is proposed. Samples with different mass percentages of nano-silver powder were fabricated and related characteristics including thermal conductivity, cycle water uptake and adsorption/desorption performance were investigated. Our experimental results show greatly improved thermal conductivity of nano-silver powder supported composite sheets. Analysis of the adsorption testing confirmed that the nano-silver powder improved dynamic adsorption performance, and adsorption rate coefficients of composite sheets increasing by 6–103% compared with that of a pure FAPO-34 coated sheet. The composite samples also exhibited better dynamic desorption performance, in that their desorption rate coefficients increased to be 1.3–2.3 times as great as those of the pure FAPO-34 sample.

Powder mixed electrical discharge machining for antibacterial coating on titanium implant surfaces

Infection in medical implantation requires a long and often costly treatment procedure which affects patient's psychology and causes death in many cases. Some methods such as ion implantation, physical vapor deposition and magnetron sputtering have demonstrated their efficiency in antibacterial coating. However, these are purely coating methods and until now, there is no method that has the ability to concurrently machine and coat an antibacterial layer on the surface of medical implants. Powder mixed electrical discharge machining (PMEDM) is therefore proposed and investigated in this study since it's a machining method with precise surface modification potential. This includes the transfer of tool electrode material as well as powder material suspended in the dielectric fluid to the workpiece. Preliminary research findings have shown that varying silver content (from 0.2% to 1.12%), depending on powder concentration suspended in the dielectric fluid, can be transferred to the modified layer. In this study, different silver nano-powder concentrations are added to a hydrocarbon-based dielectric fluid and used to machine titanium workpieces. Surface roughness, material removal rate, tool wear, pulse signals, recast layer, micro crack and resulting silver content on the workpiece are analyzed and discussed. Results show that powder concentration plays a vital role in regulating the amount of silver deposited on the machined surface. Since this directly affects the effectiveness of the coated antibacterial layer, it can therefore be shown that, with careful control, PMEDM is a promising method for concurrent machining and coating an antibacterial layer on the surface.

Functionalized Carbon Black Supported Silver (Ag/C) Catalysts in Cathode Electrode for Alkaline Anion Exchange Membrane Fuel Cells

Two kinds of non-platinum metal catalysts, 40 wt% Ag/C (Ag/C) prepared using the impregnation method and commercial nano-silver powder (commercial Ag) were used as the cathode catalysts in alkaline anion exchange membrane fuel cells (AEMFC). In the surface measurement and elemental composition analysis of the prepared Ag/C catalyst, XRD revealed that the silver nanoparticles were successfully produced and attached onto the carbon black supporter. In addition, SEM and TEM analyses showed the silver nanoparticle size catalyst was less than 20 nm in the synthesized Ag/C. EDX and TGA analyses confirmed that the actual Ag loading in the Ag/C catalyst was near the calculated value in the synthesis procedure. For AEMFC performance tests, the results showed that the maximum power densities using Ag/C, commercial Ag, and Pt/C as the cathode catalysts were 200 mW cm−2 at 0.4 V, 105 mW cm−2 at 0.3 V, and 207 mW cm−2 at 0.5 V which were consistent with the CVs and LSV characterizations. These results indicated that the performance of tested AEMFC with Ag/C and commercial Ag catalysts was 3.5% and 49.3% less than that of AEMFC with Pt/C, respectively. This study successfully implemented non-Pt catalyst for the cathode electrode in AEMFC applications.

Flame-synthesized nickel-silver nanoparticle inks provide high conductivity without sintering

A new concept for the synthesis of conductive metal nanoparticle inks (nano-inks) is introduced using a one-step continuous flame-based process. Bimetallic nickel (Ni)-silver (Ag) nanopowders are simultaneously produced and functionalized in a High Temperature Reducing Jet (HTRJ) reactor. The HTRJ process allows rapid aerosol (gas phase) formation of multicomponent metal nanoparticles with relatively high production rates from low-cost metal precursors. Octylamine, a volatile aliphatic amine, is sprayed into the reactor effluent after the particle formation zone to cap nanoparticles as they form. Ni-Ag Functionalized Nano Powders (FNPs) were characterized and compared with Bare Nano Powders (BNPs) to verify that in situ ligand attachment was successful. Nano-inks were prepared by dispersing FNPs in an organic solvent. Conductive films were fabricated using different nano-ink compositions starting from pure Ni to 50 wt% Ni. With the use of a small capping agent, films containing 50 wt% (65 at%) Ni provide an electrical conductivity of 5.14 × 104 S m−1 without any post-processing. Conductivity increased to 4.22 × 105 S m−1 after thermal annealing in an inert environment. These sintering-free bimetallic conductive nanoparticles can be used as a lower cost replacement for current silver inks for single-step printing of conductive traces without post-processing.

Obtaining of silver nanopowders by the thermal decomposition of fatty silver salts with various chain length

In the present study authors describe results of research on silver structures obtained by the thermal decomposition process of organic precursors. Silver nanoparticles obtained during process had different size and structure morphology. Length of precursors carbon chain impact on silver nanopowders quality have been proved. Obtaining particles authors paid attention on silver phase forming mechanism during silver grains aggregations, and also on structural deformation process. Temperatures of precursor decompositions were define precisely with consider of carbon atoms quantity in their carboxylate chains. Activation energy of the test specimens was analyzed with use of thermogravimetric method. The correctness of whole process—from precursors synthesis to their thermal decomposition, were investigated by NMR spectra. Examples of correct silver structures and structural deformations were characterized by SEM imaging. Classification of obtained structures allowed to determine optimal conditions for thermal decomposition process for silver nanopowders production.

The effect of silver nanoparticles incorporation in the self-etch adhesive system on its antibacterial activity and degree of conversion: an in-vitro study

Introduction: Despite of the recent advances in the adhesive dentistry, high possibility of microbial biofilm development at the resin restoration surfaces may lead to marginal gaps and recurrent caries. Degree of conversion of the dental adhesive represents a relative assessment to its quality, and a direct correlation with its mechanical behavior. This in vitro study was carried out to investigate the minimum inhibitory concentration of antimicrobial silver nanoparticles incorporated in two forms into the self-etch adhesive system and the effect of their incorporation on the degree of conversion of the self-etch adhesive. Methods: Minimum Inhibitory Concentration of the self-etch adhesive system incorporated with nanosilver powder and solution against Streptococcus mutans was tested using an agar diffusion test. The effect of nanosilver incorporation (powder and ethanol-based solution) in the self-etch adhesive system on its degree of conversion was assessed using Attenuated Total Reflectance/ Fourier Transform Infra-Red spectrometer (ATR/ FTIR). Results: The results showed that silver nanoparticles incorporation (powder or ethanol based at 12.5 µg/ml concentration) significantly increased the antibacterial efficacy of the self-etch adhesive against Streptococcus mutans (P&lt; 0.05). Nanosilver powder possessed higher significant antibacterial effect when compared to silver ethanol based solution (P&lt; 0.05). Degree of conversion of self-etch adhesive containing nanosilver powder showed non-significant difference from the control group (p &gt; 0.05). In contrast, self-etch adhesive with nanosilver solution recorded significantly lower values when compared to the control or nanosilver powder group (P&lt; 0.05). Conclusion: The antibacterial efficacy of the adhesive system can be greatly potentiated with the addition of silver nanoparticles (12µg/mL concentration) especially the nanosilver powder. Incorporation of the antibacterial nanosilver powder in the adhesive system didn’t compromise the degree of conversion of the adhesive resin.

Assistive Electro Discharge Machining of AIN Ceramics

Electro discharge machining process experiences limitation due to the non-conductive nature of the workpiece material. However, researchers proposed assistive EDM technique to machine nonconductive materials in the past. These assistive techniques require a minimal thickness of 100 µm conductive coating on the workpiece surface which usually takes longer time to coat the surface using PVD (physical vapor deposition) method. In this paper, a new modified assistive EDM method has been proposed to machine nonconductive Aluminum Nitride ceramics successfully. A three layers coating was used that included silver coating, carbon tape and silver nano-powder on a non-conductive aluminium nitride. This coating aids in conducting EDM operation due to the availability of conductive particles. Apart from the decomposition of dielectric that facilitates carbon particles on top of conductive carbon layer, coating itself also contributes in conductive silver particles. Therefore, carbon as well as silver debris that remains on the ceramics surface aids in continuous spark generation which in turn creates alternative thermal load and thus removes materials.

Preparation and characterization of silver-doped graphene-reinforced silver matrix bulk composite as a novel electrical contact material

The incorporation of graphene into silver nanopowder to prepare their bulk composite with enhanced electrical and mechanical properties is investigated. The silver-doped graphene composite (GNs–Ag) is introduced as a reinforcing phase. Silver nanopowder and GNs–Ag composite are ultrasonically mixed and plasma-sintered to prepare GNs–Ag reinforced silver matrix bulk composite. The phase structure, micromorphology, chemical state of elements of the GNs–Ag nanoparticles was analyzed in detailed. Meanwhile, micromorphology and electrical properties of the sintered bulk composites are also measured. The results showed that graphene oxide (GO) and Ag ions are simultaneously reduced by hydrazine hydrate during the reaction. Ag nanoparticles (AgNP) presents the uniformly distribution on the surface of graphene sheets. The Raman spectrum is significantly enhanced compared with that of GO due to the presence of AgNP in the GNS–Ag nanoparticles. It is observed that C/O mass ratio demonstrates an increasing trend from 1.84 in graphene oxide to 6.29 in the composites materials. Compared to International Annealed Copper Standard, this composite material possesses an electrical conductivity of 92.6%, a density of 9.59 g cm−3, and a hardness of 46.12 HV. This phenomenon can be explained as that grain boundaries will be formed at the grain boundaries of silver due to the addition of graphene. In addition, it is found that the resistance of the GNs–Ag/n-Si (111) Schottky contact is lower than Ag/n-Si (111) Schottky contact.

Electrochemical Synthesis of Ammonium Persulfate (NH4)2S2O8 Using Oxygen-Depolarized Porous Silver Cathodes Produced by Powder Metallurgy Methods

The stage-by-stage mechanism of the reduction process proceeding in an acidic environment in the cathodic depolarization of ammonium sulfate (NH4)2SO4 (including the primary process such as synthesis of hydrogen peroxide H2O2 on a porous silver cathode by equation $$ 2{\mathrm{H}}_2{\mathrm{O}}_2+2{\mathrm{S}\mathrm{O}}_4^{2-}=={\mathrm{S}}_2{\mathrm{O}}_8^{2-}+{\mathrm{O}}_2\uparrow +{\mathrm{H}}_2\mathrm{O} $$ and the main final process such as $$ 2{\mathrm{NH}}_4^{2+}+{\mathrm{S}}_2{\mathrm{O}}_8^{2-}=\left({\mathrm{NH}}_4\right){}_2{\mathrm{S}}_2{\mathrm{O}}_8\Big) $$ along with the anodic reaction, $$ 4{\mathrm{H}\mathrm{O}}_2^{-}=3{O}_2\uparrow +2{\mathrm{H}}_2\mathrm{O}+4\mathrm{e} $$ , on a platinum plate has been established. The silver cathodes were produced by powder metallurgy methods (compaction of silver nanopowder with particles 10–30 nm in diameter at 44.13 MPa followed by sintering of the samples in a purified hydrogen atmosphere at 450°C). The silver nanopowder was obtained as individual acicular nanocrystals that branched out and were held in pairs on the Pt plate in electrolysis in a 2% AgNO3 solution with addition of 1% nitric acid. The nanostate of the silver powder was verified with the BET method (Brunauer, Emmett, Teller) by low-temperature nitrogen adsorption. The ammonium persulfate synthesis kinetics and mechanism indicate that the replacement of commercial lead cathodes with oxygen-polarized silver cathodes leads to a 17.5% decrease in the electricity consumed. The polarization properties of the cellular silver cathode remain unchanged for 100 h of (NH4)2SO4 electrolysis.

Synthesis of dendritic silver nano powder using pulsing electrolysis in ammonia solution

A method to produce nano silver structures with high purity is pulsing electrolysis. In this paper the effects of potential, ammonia concentration (NH3), silver ion concentration [Ag+], total time, Ton, Toff and Trev on this process were studied. The considered parameters were varied as follows: electrical potential = 5 ? 10 V; [NH3] = 40 ? 80 g/L; [Ag+] = 0.1 ? 0.5 g/L; total time = 15 ? 30 min; Ton = 1 ? 8 ms; Toff = 1 ? 8 ms; and Trev = 0 ? 4 ms. In order to optimize these parameters, the fractional factorial design of experiments was used. A silver dendritic structure was produced with nano size arm. The phase composition and morphology of the synthetized dendritic silver nanostructures was determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The optimum condition to synthesize the dendritic silver nano powders were 7.52 V; [NH3] = 64.75 g/L; [Ag+] = 0.45 g/L; total time = 17.59 min; Ton = 6.97 ms; Toff = 4 ms; and Trev = 1.89 ms. A mathematical model was also presented. The predicted silver nano size dendrite arm at the optimum condition was found to be 87.29 nm which was very close to the experimental value of 90 nm.

Performance Analysis of Silver-Based Graphene Nanocomposite Bulk Materials Obtained by Spark Plasma Sintering

Silver-based bulk materials containing Ag/reduced graphene oxide (Ag/rGO) nanocomposite were prepared via a two-step procedure. First, a one-pot procedure was used to form Ag/rGO nanocomposites from AgNO3 and GO using hydrazine as a reductant. Then, Ag/rGO nanocomposites with various graphene contents were mixed with silver nanopowder and consolidated using spark plasma sintering. The hardness of the bulk material increased to 70 HV when the graphene content was increased to 2.5 wt.%. The bulk densification varied from 87.2% to 96% and was highest at graphene content of 2.5 wt.%. The conductivity (43.00–53.73 MS/m) was highest at 0.7 wt.% graphene content. The variation of the intensity and conductivity is mainly related to the formation of Ag-C bonds, while the variation of the density is mainly related to the sintering process.

Synthesis of a simply modified electrochemical nicotine sensor based on silver nanoparticles

An innovative electrochemical nicotine modified sensor was created by chemically mixing a carbon paste with silver nano powder to prepare an Ag nanoparticle modified carbon paste electrode. Different electrochemical techniques including cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy in both aqueous and micellar media were used. The surface morphology was also detected using scanning electron microscope and energy dispersive X-ray analysis techniques. Nicotine measurements were investigated in Britton–Robinson buffer solutions with a pH range of 2.0–8.0 containing 1.0 mmol/L sodium dodecyl sulfate. The electrode-based NIC sensor exhibited a high sensitivity in quantitative analysis, and its detection limit could be as low as 0.0036 μmol/L with linearity ranging from 0.8 μmol/L to 800 μmol/L. In addition, due to its good reproducibility, anti-interference performance, and long-term stability, the proposed sensor is capable of detecting trace levels of nicotine in urine samples and different brands of commercial cigarettes.

Synthesis and antibacterial activity of water-dispersible silver nanoparticles via micellar nanoreactors

We have synthesized silver nanoparticles (AgNPs) using micelles of sugar fatty acid ester by dissolving the surfactant in a mixture of iso-octane and n-butanol, with solid-liquid extraction. Highly concentrated, water-dispersible AgNPs were obtained after thorough washing with alcohol, to remove excess of sucrose fatty acid ester DK SS and salt, followed by drying. The particles were characterized for their size, morphology and crystallinity using UV-Visible spectrophotometry, Transmission Electron Microscopy and x-ray diffractometry. Antibacterial study, confirmed the activity of nanoparticles against E. coli, P. aeruginosa and S. aureus, which causes diseases including diarrhoea and several life-threatening infections. Antibacterial activity of E. coli and P. aeruginosa was found to be 2.5 fold and for S. aureus 1.6 fold compared to 50 ppm conc. of Silver Nitrate. Our method of producing nanoparticles is employed as a platform technology for synthesizing other inorganic nanoparticles. This is the first report discussing the use of micellar carriers for obtaining silver nanopowder, to the best of our knowledge, which has the potential to overcome limitations during fabrication of AgNPs using reverse/inverse micelles. Our method yielded nano-sized, water-dispersible AgNPs via an easy and economic approach. The one-pot approach possesses advantages in terms of cost and simplicity, as compared with traditional methods of producing powdered AgNPs using energy intensive and expensive techniques like lyophilisation. The developed method, thus, possesses immense potential for commercial synthesis of AgNPs.

Thermal interface materials based on graphene and silver nanopowder

PurposeThe purpose of this paper is to present results of the studies on modification of ethylene-vinyl acetate (EVA) encapsulation foil to be used as thermal interface material (TIM). It is estimated that poor thermal management in electronic devices can cause over 50 per cent of failures. As the junction temperature rises, the failure rate for electronics increases exponentially. To ensure sufficient heat transfer from its source, TIMs are used in various circuits. On the other hand, it is important to ensure high electric resistivity of the designed TIM.Design/methodology/approachThe focus of the investigation was twofold: modification of EVA with both graphene oxide (GO) and silver nanopowder (nAg); and TIM applicability through lamination of photovoltaic cells with standard and modified EVA foil. The main problem of a new type of encapsulant is proper gas evacuation during the lamination process. For this reason, reference and modified samples were compared taking into account the percentage of gas bubbles in visible volume of laminated TIM. Finally, reference and modified TIM samples were compared using differential scanning calorimetry (DSC) and laser flash analysis (LFA) measurements.FindingsThe proper parameters of the lamination process for the modified EVA foil - with both GO and organometallic nAg particles - were selected. The nAg addition results in an increase in thermal conductivity of the proposed compositions with respect to unmodified EVA foil, which was confirmed by DSC and LFA measurements.Originality/valueThe experiments confirmed the potential application of both EVA foil as a matrix for TIM material and nAg with GO as an active agent. Proposed composition can bring additional support to a solar cell or other electronic components through effective heat removal, which increases its performance.

Silver nanoparticles: characterization and antibacterial properties

In this study, two aqueous suspensions of silver nanoparticles, nano silver powder (Sigma Ag-NPs) and nano silver ink (Ink Ag-NPs), were characterized for studying their antibacterial activity. The X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) were used to determine the crystal structure, shape and size of Ag-NPs. The bactericidal effects of these nanoparticles were investigated against gram positive and gram negative bacteria at two different concentrations, 10 and 50 $$\upmu $$ g/disc, by the disk diffusion method using Mueller–Hinton Agar to display good microbial culture growth. Antibacterial experiments results revealed that Escherichia coli (ATCC25922) and Bacillus subtilis (ATCC6633) inhibited by Ink Ag-NPs more than Sigma Ag-NPs. Both Salmonella typhimurium (ATCC14028) and Staphylococcus aureus (ATCC25923) were resistant to both sources of Ag-NPs, while Pseudomonas aeruginosa (ATCC27853) was resistant to Ink Ag-NPs and inhibited by Sigma Ag-NPs. This experiment showed that characteristics and suspension stability of Ag-NPs affect its antibacterial activity against some pathogenic bacterial strains.