Extracellular Biosynthesis Of Silver Nanoparticles Research Articles

Green synthesis and antibacterial-antibiofilm properties of biogenic silver nanoparticles

The biosynthesis of metallic nanoparticles is gaining prominence as an alternative to traditional physicochemical methods, offering several advantages such as simplicity, non-toxicity, lower energy requirements and short reaction times leading to environmentally sustainable processes. The aims of this work were: to study the extracellular biosynthesis of silver nanoparticles (AgNPs) by Pseudomonas extremaustralis 2E-UNGS, to characterise the shape, monodispersity and size of AgNPs, to explore their antimicrobial and antibiofilm activities, and to evaluate the role of nitrate reductase activity in the biosynthesis process. The novelty of this work relies on the development of a green and sustainable method for the synthesis of stable AgNPs with optimal properties for potential applications in antimicrobial materials, especially when incorporated into polymeric matrices or used as agrochemical substitutes. Optimal conditions for the biosynthesis of spherical AgNPs were determined to be pH 7, 38 °C, 4 h of darkness and 120 rpm using stationary phase culture supernatants of P. extremaustralis 2E-UNGS. The involvement of extracellular nitrate reductase in AgNP biosynthesis was confirmed by enzymatic assays and supported by bioinformatics analysis, which identified the presence of the napA2 gene linked to the nirBD cluster. Antimicrobial assays demonstrated the inhibitory effect of AgNPs against both Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa PA01 in both planktonic and biofilm states. In addition, the potential application of AgNPs in innovative antibacterial polymers was explored by incorporating them into polyurethane matrices either alone (PU-AgNP) or in combination with crystal violet as a photosensitizer (PU-AgNP-CV). Subsequent inoculation with a clinical isolate of Pseudomonas aeruginosa resulted in significant reductions in viable bacterial counts on both PU-AgNP-CV and PU-AgNP. Biogenic AgNPs showed antibacterial and antibiofilm properties for new antimicrobial material development.

Optimization, characterization of silver nanoparticles from the young leaves of Pancratium telanganense and application studies against pathogen bacteria

Optimization of nature friendly and consistent developments of the green synthesis of nanoparticles have engrossed encouraged in nanotechnology since of its marvelous incentive in modifying metals into nano size to its probable use for human welfares. The present report reveals the young leaves of Pancratium telanganense was exposed for extra-cellular bio-synthesis of silver nanoparticles (AgNPs) and its antibacterial actions against bacterial pathogens The eco-friendly biosynthesized AgNps optimized then considered by UV spectrum, FTIR, TEM. Then formed AgNPs were confirmed against bacterial test organisms. The young leaves of Pancratium telanganense were establish to be a noble fabricator of AgNPs. Expansion maximizes exhibited absorbance of 420–425 nm at pH-7, 25 °C with 1 mM AgNO3 concentration and 100 mg of leaves powder crude extract. Auxiliary TEM discovered the types of formation of irregular, fine discrete nanoparticles with size ranging between 20 to 35 nm, the FTIR illustrations the bands at 1644 and 153 8 cm−1 consistent to the necessary ambiances of bands of proteins. Antibacterial activities against bacterial pathogens exhibited good results have shown the maximum inhibition zone about 18 mm and 17 mm respectively at 60 μl of AgNps.

Mycosynthesis of silver nanoparticles using marine fungi and their antimicrobial activity against pathogenic microorganisms

ObjectivesAt the present time, there is a persistent need to get rid of environmental contaminants by eco-friendly, sustainable, and economical technologies. Uncontrolled disposal practices of domestic and industrial solid and liquid wastes led to water pollution which has negative impacts on public health, environment, and socio-economic development. Several water-borne diseases are spreading man to man by microorganisms such as pathogenic bacteria. For the protection of water bodies, all wastewater from various sources should be managed and remediated properly. Myco-remediation is a form of bioremediation in which fungi are used to get rid of contaminants. Fungi are attractive agents for the biosynthesis of nanoparticles especially silver nanoparticles (AgNPs) which are considered one of the most widely utilized nanoparticles because of their unique characteristics such as antibacterial, antiviral, antifungal, and anti-inflammatory properties. MethodsThis study uses silver nitrate and supernatants of four marine fungi; Penicillium simplicissimum, Aspergillus terreus, Aspergillus japonicus, and Aspergillus oryzae for extracellular biosynthesis of silver nanoparticles and to evaluate its activity against different pathogenic microorganisms. These nanoparticles may subsequently be applied for the treatment or nano-bioremediation of microbial contaminants in water bodies and improve water quality. ResultsSilver nanoparticles were synthesized and the results revealed that spherical and well-dispersed nanoparticles of different sizes were formed with sizes ranging between 3.8 and 23 nm. Characterization results approved the existence of stable nanocrystalline elemental silver. Antibacterial activity results revealed that AgNPs can be used as a powerful antimicrobial agent for several pathogenic bacteria, yeast, and fungi. Among the biosynthesized NPs mediated by the four marine fungi, AgNPs mediated by A. japonicus (5 mM) had the highest antibacterial activity, while AgNPs mediated by Penicillium simplicissmum (8 mM) had the highest antifungal activity. ConclusionMarine fungi can biosynthesize stable AgNPs that exhibit potent antimicrobial activity against a variety of pathogens.

Isolation, Identification, Chemical and Biological Synthesis of silver nanoparticles andits Antimicrobial Activity

Abstract: Extracellular biosynthesis of silver nanoparticles (AgNPs) by Aspergillus Fumigatus isolated from Soil was reported in the present study. The biosynthesis of AgNPs was monitored by ultraviolet-visible spectroscopy and its antimicrobial activity, Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC). The isolated fungus was identified by observing morphological characteristics and Lactophenol cotton blue staining and confirmed as Aspergillus fumigatus from the report given by National Fungal Culture Collection of India (NFCCI). Based on the study, it is concluded that the AgNP’s which is produced by biological methods is showing the antimicrobial activity

Study of Antibacterial and Anticancer Properties of bioAgNPs Synthesized Using Streptomyces sp. PBD-311B and the Application of bioAgNP-CNC/Alg as an Antibacterial Hydrogel Film against P. aeruginosa USM-AR2 and MRSA.

Here, we report the extracellular biosynthesis of silver nanoparticles (AgNPs) and determination of their antibacterial and anticancer properties. We also explore the efficacy of bioAgNPs incorporated in cellulose nanocrystals (CNCs) and alginate (Alg) for the formation of an antibacterial hydrogel film. Streptomyces sp. PBD-311B was used for the biosynthesis of AgNPs. The synthesized bioAgNPs were characterized using UV-Vis spectroscopy, TEM, XRD, and FTIR analysis. Then, the bioAgNPs’ antibacterial and anticancer properties were determined using TEMA and cytotoxicity analysis. To form the antibacterial hydrogel film, bioAgNPs were mixed with a CNC and Alg solution and further characterized using FTIR analysis and a disc diffusion test. The average size of the synthesized bioAgNPs is around 69 ± 2 nm with a spherical shape. XRD analysis confirmed the formation of silver nanocrystals. FTIR analysis showed the presence of protein capping at the bioAgNP surface and could be attributed to the extracellular protein binding to bioAgNPs. The MIC value of bioAgNPs against P. aeruginosa USM-AR2 and MRSA was 6.25 mg/mL and 3.13 mg/mL, respectively. In addition, the bioAgNPs displayed cytotoxicity effects against cancer cells (DBTRG-0.5MG and MCF-7) and showed minimal effects against normal cells (SVG-p12 and MCF-10A), conferring selective toxicity. Interestingly, the bioAgNPs still exhibited inhibition activity when incorporated into CNC/Alg, which implies that the hydrogel film has antibacterial properties. It was also found that bioAgNP-CNC/Alg displayed a minimal or slow release of bioAgNPs owing to the intermolecular interaction and the hydrogel’s properties. Overall, bioAgNP-CNC/Alg is a promising antibacterial hydrogel film that showed inhibition against the pathogenic bacteria P. aeruginosa and MRSA and its application can be further evaluated for the inhibition of cancer cells. It showed benefits for surgical resection of a tumor to avoid post-operative wound infection and tumor recurrence at the surgical site.

Extracellular biosynthesis of silver nanoparticles using Bacillus subtilis and their antibacterial activity against clinical bacterial species

The aims of this study were to biosynthesize silver nanoparticles (AgNPs) using Bacillus subtilis supernatant, and to evaluate their in vitro antibacterial potential against human pathogens; namely Staphylococcus aureus (Staph. aureus) and Escherichia coli (E. coli). Nanoparticles (NPs) are becoming popular in different fields of research, and are useful in combating vast number of microbial diseases. NPs may be artificially synthesized in vitro using chemical methods andor via extracellular metabolites produced by the bacterial strains. In the present study, biosynthesis of AgNPs was carried out in vitro using supernatants of B. subtilis. Biosynthesized AgNPs were characterized through several physical methods. The recorded Z-average (d. nm) was 135.0 nm; with 99.2 % of the NPs displaying a hydrodynamic distance across of 188.0 nm (SD= 117.7). The polydispersity index was 0.246 and the Zeta-potential value was - 17.2 mV, which indicates good colloidal stability. Results of the Transmission electron microscope (TEM) observation indicated that the particles were spherical in shape with an average size of 21.8- 27.5 nm. The antibacterial efficacy of the AgNPs against Methicillin resistant Staph. aureus (MRSA) and E. coli clinical isolates was evaluated in vitro using the agar well diffusion. The AgNPs demonstrated antibacterial potential against MRSA and E. coli isolates; recording 18 and 15 mm diameter of zones of inhibition, respectively. The minimum inhibitory concentration (MIC) was found to be 142 µg/ ml, while the recorded minimum bactericidal concentration (MBC) was 284 µg/ ml. The mode of action of the AgNPs was investigated using the Scanning electron microscope (SEM), which was recognized as bacterial cell lysis and elongation. Current data suggest an efficient biosynthesis of stable AgNPs by B. subtilis with remarkable antibacterial potential.

Entomopathogenic Fungi Biomass Production and Extracellular Biosynthesis of Silver Nanoparticles for Bioinsecticide Action

Entomopathogenic fungi are microbial agents of insect control in nature. They have been used as biologic strategies to manage insect invasion; however, the challenge is to maintain their shelf life and viability when exposed to high temperatures, ultraviolet radiation, and humidity. Synthesized silver nanoparticles (AgNPs) from fungal extracellular enzymes are an alternative using these microorganisms to obtain nanoparticles with insecticidal action. The present study evaluates the biomass production and the potential to synthesize silver nanoparticles using entomopathogenic fungi isolates. Sixteen isolates of entomopathogenic fungi were used in this study. The fungi pathogenicity and virulence were evaluated using the insect model Tenebrio molitor, at a concentration of 5 × 106 conidia/mL. The fungal biomass was produced in a liquid medium, dried, and weighed. The synthesis of silver nanoparticles was performed with aqueous extracts of the entomopathogenic fungi and silver nitrate solution (1 mM), following characterization by a UV/vis spectrophotometer, mean size, and polydispersity index. The results showed a significant variation in pathogenicity, virulence, and biomass production among the evaluated fungi isolates; however, only one of the isolates did not have the potential to synthesize silver nanoparticles. Pearson’s correlation showed significant correlation values only between virulence × biosynthesis potential and biomass production × biosynthesis potential, both with negative values, indicating an inverse correlation. Thus, AgNPs with entomopathogenic fungus extract can produce an innovative bioinsecticide product using a green production process.

Effect of Optimization Factors on the Production of Bacillus subtilis and Escherichia coli Synthesized Silver Nanoparticles

The recent discovery of silver nanoparticles and their production from Bacillus subtilis and Escherichia coli have enhanced optimization attempts. Extracellular biosynthesis of silver nanoparticles using the Bacillus subtilis and Escherichia coli cultured supernatants was done according to standard procedures. Optimization of the production of silver nanoparticles was done in a 3 X 3 (three factors) design involving temperature (25, 30 and 35 degrees), pH (6, 7 and 8), and time of incubation (24, 48 and 72 Hours) in a total of 15 non-randomized runs. The result showed a sharp decline in the synthesis of B. subtilis silver nanoparticles (BNP) within the first 40 hours but attained steady optimization between 40 – 60 mins. An exponential increase in BNP synthesis was observed between pH 6 – 7 with a slight decline observed between pH 7 – 8. An increase in temperature from 25-300C resulted in a decrease in the production of BNP while the production of BNP increased over 30-350C. An initial lag in Escherichia coli synthesized silver nanoparticle (ENP) synthesis was observed with temperature variations. ENP synthesis maintained an exponential increase up to pH 7 but decreased with 7>pH≤8. The results showed that the increase in temperature resulted in a gradual decrease in production of ENP producing a negative slope. Therefore, the variations in optimization factors of silver nanoparticles produced from both B. subtilis and E. coli led to improved production.

Extracellular Biosynthesis of Silver Nanoparticles Using Aquatic bacterial Isolate and its Antibacterial and Antioxidant Potentials

Extracellular Biosynthesis of Silver Nanoparticles Using Aquatic bacterial Isolate and its Antibacterial and Antioxidant Potentials

Biosynthesis of Silver Nanoparticles through Biomass of Fungus Aspergillusniger and their Antibacterial Potential

Extracellular biosynthesis of silver nanoparticles by fungus Aspergillus niger which was isolated from waste water is being reported in the present paper. The production of silver nanoparticles was evidenced by UV-Vis spectrum, showing the absorbance between 260 to 400 nm. The nanoparticles characterized by Scanning Electron Microscopy exhibited silver nanoparticles with diameter of 25nm to 75nm. Energy Dispersive X-ray analysis reveals strong signals in the silver region and confirms the formation of the silver nanoparticles. The Fourier Transform Infrared Spectroscopy study confirmed that the A. niger mycomass has the ability to perform both reduction and capping functions on the silver nanoparticles. Compound Microscopy confirms the self-assembling property of silver nanoparticles. The silver nanoparticles showed remarkable antibacterial activity against Lactobacillus plantarum, Lactobacillus delbrueckii and Bacillus subtilis bacterial strains. Reduction of silver ions is an extracellular and rapid process; this information may lead to the development of easy protocols for biosynthesis of the silver nanoparticles. Antibacterial activity of silver nanoparticles is important for the development of effective antibacterial agent against those bacteria who are showing resistance against antibiotic drugs which are available in market.

Extracellular synthesis of silver nanoparticles by Thiosphaera pantotropha and evaluation of their antibacterial and cytotoxic effects.

Extracellular biosynthesis of silver nanoparticles (AgNPs) was explored using Thiosphaera pantotropha since this strain exhibits both nitrate- and nitrite-reductase enzyme activity (NaR and NiR, respectively). Optimal AgNP synthesis was achieved using 2mM AgNO3, culture supernatant of nutrient broth grown T. pantotropha, and incubation at 37°C and 180rpm. Under these conditions, the localized surface plasmon resonance peak of silver at 404nm matched well with the average size of the spherical AgNPs based on FEG-TEM micrographs, i.e., 14.6nm (range: 5-51nm). The zeta potential of -33.6mV indicated good stability of the biosynthesized nanoparticles. The XRD spectra demonstrated the simultaneous presence of face-centered cubic crystal structure of AgNPs and AgCl NPs. Ag+ ions were possibly reduced by the NaR and NiR enzymes released into the culture media. The FTIR spectra confirmed the stabilization of the AgNPs by biomolecules present in the culture supernatant of T. pantotropha. The synthesizedAg/AgCl NPs exhibited good antibacterial efficacy against both Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus). The minimum inhibitory concentration (MIC) was 2.5µg/ml for all the bacteria except B. subtilis (MIC of 10µg/ml). The minimum bactericidal concentration (MBC) was 2.5, 10, 20, and 5µg/ml for E. coli, P. aeruginosa, B. subtilis, and S. aureus, respectively. At MBC and higher AgNP concentration, both plating and CLSM imaging confirmed the absence of viable bacteria in treated water. The biogenic AgNPs depicted IC50 of 34.8µg/ml for MCF-7 cells.

WITHDRAWN: Extracellular biosynthesis of silver nanoparticles using Aspergillus terreus: Evaluation of its antibacterial and anticancer potential

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Biosynthesis of silver nanoparticles mediated by culture filtrate of lactic acid bacteria, characterization and antifungal activity

Abstract Silver nanoparticles (AgNPs) are nanomaterials obtained by nanotechnology and due to their antimicrobial properties have a major importance in the control of various species of bacteria, fungi and viruses, with applications in medicine, cosmetics or food industry. The goal of the paper was to present the results of the research carried out on rapid extracellular biosynthesis of silver nanoparticles mediated by culture filtrate of lactic acid bacteria Lactobacillus sp. strain LCM5 and to assess the antimicrobial activity. Analysis of transmission electron microscopy (TEM) micrographs evidenced that the size of AgNPs synthesized using culture filtrates of lactic acid bacteria strain LCM5 ranged between 3 and 35 nm diameter, with an average particle size of 13.84±4.56 nm. AgNPs presented a good dispersion, approximately spherical shape, with parallel stripes certifying crystal structure. Frequency distribution revealed that preponderant dimensions of biosynthesized AgNPs were below 20 nm (94%). Antimicrobial activity of AgNPs was variable depending on both species and group of test microorganisms (bacteria or fungi) involved. Diameter of growth inhibition zone of Aspergillus flavus and Aspergillus ochraceus caused by silver nanoparticles synthesized by lactic acid bacteria strain LCM5 were similar (12.39 ± 0.61mm and 12.86 ± 0.78 mm) but significant stronger inhibition was registered against Penicillium expansum (15.87 ± 1.01mm). The effectiveness of biosynthesized silver nanoparticles was more pronounced against Gram-negative bacteria Chromobacterium violaceum with larger zone of inhibition (18 ± 0.69 mm diameter) when compared to those from fungi. Results recommend the silver nanoparticles biosynthesized using culture filtrate of the lactic acid bacteria Lactobacillus sp. strain LCM5 for biotechnological purposes, as promising antimicrobial agents.

Extracellular Biosynthesis of Silver Nanoparticles using Bacterial Isolate from Saline Soil

Extracellular Biosynthesis of Silver Nanoparticles using Bacterial Isolate from Saline Soil

Enhancement of Antibiotics activity by microbially synthesized silver nanoparticles

Biological synthesis of nanoparticles is a promising approach that is comparatively inexpensive and eco-friendly. Among various microorganisms, actinobacteria have been found to be efficient in the synthesis of nanomaterials. In thisstudy, extracellular biosynthesis of silver nanoparticles (Ag-NPs) was investigated by mixing silver nitrate with culture filtrate of Streptomyces rochei strain MFA-37.The biosynthesized Ag-NPs were characterized by UV–Vis spectrophotometric analysis, and showed a peak of absorbance at 440 nm. Fourier transform infrared (FTIR) analysis showed amines and amides that are responsible for the stabilization of Ag-NPs. The morphology and size of nanoparticles were determined using high-resolution transmission electron microscopy, XRD and DLS techniques which indicated well dispersed, spherical Ag-NPs sized 2–20 nm, and the zeta potential of AgNPs reached -20.5 mV. Enhancement of antibacterial activity of fourteen antibiotics was conducted by combining antibiotics with synthesized AgNPs. The synergistic activities of AgNPs combination with antibiotics were determined using disc diffusion against two multi-drug resistant Staphylococcus aureus SA-185 and SA-325 recovered from Libya. The highest synergistic effects were 6.11 and 6.37 folds for Penicillin followed by 6.11 and 4.44 folds for Ciprofloxacin and 6.11 and 3.69 folds for Erythromycin for MRSA-185 and MRSA-325 , respectively. This activity of AgNPs and antibiotics could be valuable for the manufacture of hybrid drugs to kill or inhibit the MRSA infection especially in case of superficial injuries.

Extracellular Biosynthesis of Silver Nanoparticles from Soil-isolated Streptomyces sp. NBrR7 and its Antibacterial and Anticancer Activities

Extracellular Biosynthesis of Silver Nanoparticles from Soil-isolated Streptomyces sp. NBrR7 and its Antibacterial and Anticancer Activities

Study on bioactive molecules involved in extracellular biosynthesis of silver nanoparticles by Penicillium aculeatum Su1

In this paper, the biosynthesis of high-stable and biocompatible silver nanoparticles (AgNPs) was implemented by employing cell-free filtrate of Penicillium aculeatum Su1. The compositions analysis of reducing biomolecules in reaction system before and after AgNPs synthesis suggested that proteins were mainly involved in the biosynthesis process of AgNPs. Polyacrylamide gel electrophoresis (SDS-PAGE) analysis displayed that two main protein bands with molecular weights ranging from 66.2 to 116 KDa and 35 to 45 KDa were capped on the surface of AgNPs. The further identification of these protein bands by liquid chromatography-mass spectrometry (LC-MS/MS) analysis indicated that actin as a major protein component was responsible for stabilization of prepared AgNPs. The activity of nitrate reductase secreted by P. aculeatum Su1 was 73.73 ± 3.89 μg/(g · h). Furthermore, the dialysis assay showed that small molecular components had significant impacts on yield and particle size of biosynthesized AgNPs. Reduced nicotinamide adenine dinucleotide or reduced nicotinamide adenine dinucleotide phosphate (NADH or NADPH)-dependent nitrate reductases and other types of reductases or non-enzymatic bioactive molecules (≥ 3.5 KDa) might simultaneously participate in the biosynthesis process of AgNPs mediated by P. aculeatum Su1.

Extracellular biosynthesis of silver nanoparticles from Penicillium italicum and its antioxidant, antimicrobial and cytotoxicity activities.

The synthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic activities was investigated and extracellularly biosynthesized using Penicillium italicum isolated from Iraqi lemon fruits. The formation of synthesized nanoparticles was observed after 72h of incubation. Color changing, ultraviolet and visible spectrum, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and energy dispersive analysis X- ray confirmed the biosynthesis and characterization of silver nanoparticles. Ultravioletandvisible spectroscopy showed silver surface plasmon resonance band at 415nm. X- ray diffraction showed that the particles were crystalline with face-centered cubic lattice phase and a size of 39.5nm. Fourier transform infrared analysis shows the possible interactions between silver and bioactive molecules, which may be responsible for synthesis and stabilization of silver nanoparticles. Scanning electron microscopy imaging revealed different morphologies of the AgNPs, some of nanoparticles were close to spherical in shape, while others had platelet like structure, in size range between 32 and 100nm. The transmission electron microscopy image demonstrated that AgNPs were spherical with a size < 50nm. The biosynthesized silver nanoparticles were proved to be potential antioxidants by showing effective radical scavenging activity against 2, 2-diphenyl-1-picrylhydrazyl, hydroxyl radical and resazurin. The nanoparticles also showed potent antimicrobial activity against various pathogens, including bacteria and fungi as well as significant concentration-dependent cytotoxic effects against human breast cancer cells. The powerful bioactivity of the synthesized silver nanoparticles recommends their biomedical use as antioxidant, antimicrobial as well as cytotoxic agents.

Microbial Synthesis and Characterization of Silver Nanoparticles using Alternaria alternata

In this study, extracellular biosynthesis of silver nanoparticles (AgNPs) was carried out using Alternaria alternata. AgNPs were synthesized using vegetative and cell-free filtrate methods. Silver nitrate (AgNO3) solution was reduced with fungal mycelial mass and cell-free filtrate at a ratio of 1:4 (v/v). Further, the effects of biosynthesis parameters (reaction time, reaction temperature, light and dark incubation, and static and agitated conditions) weredetermined. The structural integrity of the synthesized AgNPs was investigated through UV-visible spectrophotometry, X-ray diffraction (XRD) analysis, and transmission electron microscopy (TEM). Parameter optimization revealed that cell-free filtrate AgNP synthesis at 40 °C with constant agitation and incubation in darkness for 120 h using 1 mM AgNO3resulted in the highest absorbance value (at 400 nm). Further, TEM images showed that the synthesized AgNPs were spherical, homogeneous, and well dispersed while the XRD peaks confirmed the purity of the AgNPs obtained. The diameters of the AgNPs were found to range from 7.48 to 12.15 nm. This study identifies Alternaria alternata as a potential candidate for use in the industrial biosynthesis of AgNPs.

Extracellular Biosynthesis, Characterization and Cytotoxic Effect of Silver Nanoparticles by Streptomyces coelicoflavus KS-3.

The present work aimed to investigate extracellular biosynthesis of silver nanoparticles (AgNPs) mediated by an actinomycete strain and their cytotoxic effects compared with silver ions. The selected strain was identified as Streptomyces coelicoflavus KS-3 by phenotypical characteristics and 16S rRNA analysis. The formation of biosynthesized AgNPs was proved by an absorption peak observed at 437 nm. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses revealed that the prepared AgNPs were spherical or approximately spherical followed by a small amount of truncated triangular, quadrangular and hexagonal with the particle diameters ranging from 2.33 to 91.3 nm. X-ray diffraction (XRD) pattern confirmed that the AgNPs presented a face-centered cubic (FCC) structure of crystalline silver. Energy dispersive of X-ray (EDX) spectrum and Fourier transform infrared spectroscopy (FTIR) analyses verified the existence of biomolecules, such as proteins, that participated in the formation and stabilization of AgNPs. Furthermore, the comparative study on cytotoxic effect of AgNPs indicated that the AgNPs exhibited higher biocompatibility towards human bronchial epithelial (HBE) cells than silver ions and exerted potent cytotoxic effect in a dose-dependent manner against human lung squamous cell carcinoma cells (HTB-182) and human lung adenocarcinoma cells (A549) with the concentrations ranging from 1 to 50 μg/mL.