scholarly journals Synthesis of silver nanoparticle-decorated hydroxyapatite (HA@Ag) poriferous nanocomposites and the study of their antibacterial activities

RSC Advances ◽  
2018 ◽  
Vol 8 (73) ◽  
pp. 41722-41730 ◽  
Author(s):  
Zhihui Ni ◽  
Xiuxian Gu ◽  
Yali He ◽  
Zhihua Wang ◽  
Xueyan Zou ◽  
...  

We demonstrate a facile and green rapid approach for the synthesis of uniform poriferous hydroxylapatite (HA) and poriferous silver nanoparticles (Ag NPs)-decorated hydroxylapatite (HA@Ag) nanocomposites with excellent antibacterial properties.

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2486 ◽  
Author(s):  
Yan Yang ◽  
Zhijie Zhang ◽  
Menghui Wan ◽  
Zhihua Wang ◽  
Xueyan Zou ◽  
...  

Polyvinyl alcohol (PVA) electrospun nanofibers (NFs) are ideal carriers for loading silver nanoparticles (Ag NPs) serving as antibacterial materials. However, it is still a challenge to adjust the particles size, distribution, and loading density via a convenient and facile method in order to obtain tunable structure and antimicrobial activities. In this study, Ag NPs surface decorated PVA composite nanofibers (Ag/PVA CNFs) were fabricated by the solvothermal method in ethylene glycol, which plays the roles of both reductant and solvent. The morphology and structure of the as-fabricated Ag/PVA CNFs were characterized by scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, X-ray diffraction, UV-visible spectroscopy, and Fourier transform infrared spectroscopy. Ag NPs had an average diameter of 30 nm, the narrowest size distribution and the highest loading density were successfully decorated on the surfaces of PVA NFs, at the AgNO3 concentration of 0.066 mol/L. The antibacterial properties were evaluated by the methods of absorption, turbidity, and growth curves. The as-fabricated Ag/PVA hybrid CNFs exhibit excellent antimicrobial activities with antibacterial rates over 98%, especially for the sample prepared with AgNO3 concentration of 0.066 mol/L. Meanwhile, the antibacterial effects are more significant in the Gram-positive bacteria of Staphylococcus aureus (S. aureus) than the Gram-negative bacteria of Escherichia coli (E. coli), since PVA is more susceptive to S. aureus. In summary, the most important contribution of this paper is the discovery that the particles size, distribution, and loading density of Ag NPs on PVA NFs can be easily controlled by adjusting AgNO3 concentrations, which has a significant impact on the antibacterial activities of Ag/PVA CNFs.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Lei Huang ◽  
Hongtao Yang ◽  
Yanhua Zhang ◽  
Wei Xiao

Using graphene oxide as substrate and stabilizer for the silver nanoparticles, silver nanoparticles-graphene oxide (Ag NPs/GO) composites with different Ag loading were synthesized through a facile solution-phase method. During the synthesis process, AgNO3on GO matrix was directly reduced by NaBH4. The structure characterization was studied through X-ray diffraction (XRD), atomic force microscopy (AFM), high-resolution transmission electron microscope (HRTEM), ultraviolet-visible spectroscopy (UV-Vis), and selected area electron diffraction (SAED). The results show that Ag nanoparticles (Ag NPs) with the sizes ranging from 5 to 20 nm are highly dispersed on the surfaces of GO sheets. The shape and size of the Ag NPs are decided by the volume of initial AgNO3solution added in the GO. The antibacterial activities of Ag NPs/GO nanocomposites were investigated and the result shows that all the produced composites exhibit good antibacterial activities against Gram-negative (G−) bacterial strainEscherichia coli(E. coli) and Gram-positive (G+) strainStaphylococcus aureus(S. aureus). Moreover, the antibacterial activities of Ag NPs/GO nanocomposites gradually increased with the increasing of volume of initial AgNO3solution added in the GO and this improvement of the antibacterial activities results from the combined action of size effect and concentration effect of Ag NPs in Ag NPs/GO nanocomposites.


Antibiotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 68 ◽  
Author(s):  
Mahsa Eshghi ◽  
Hamideh Vaghari ◽  
Yahya Najian ◽  
Mohammad Najian ◽  
Hoda Jafarizadeh-Malmiri ◽  
...  

Silver nanoparticles (Ag NPs) were synthesized using Juglans regia (J. regia) leaf extract, as both reducing and stabilizing agents through microwave irradiation method. The effects of a 1% (w/v) amount of leaf extract (0.1–0.9 mL) and an amount of 1 mM AgNO3 solution (15–25 mL) on the broad emission peak (λmax) and concentration of the synthesized Ag NPs solution were investigated using response surface methodology (RSM). Fourier transform infrared analysis indicated the main functional groups existing in the J. regia leaf extract. Dynamic light scattering, UV-Vis spectroscopy and transmission electron microscopy were used to characterize the synthesized Ag NPs. Fabricated Ag NPs with the mean particle size and polydispersity index and maximum concentration and zeta potential of 168 nm, 0.419, 135.16 ppm and −15.6 mV, respectively, were obtained using 0.1 mL of J. regia leaf extract and 15 mL of AgNO3. The antibacterial activity of the fabricated Ag NPs was assessed against both Gram negative (Escherichia coli) and positive (Staphylococcus aureus) bacteria and was found to possess high bactericidal effects.


2015 ◽  
Vol 17 (33) ◽  
pp. 21243-21253 ◽  
Author(s):  
Fwu-Long Mi ◽  
Shao-Jung Wu ◽  
Wen-Qi Zhong ◽  
Cheng-Yu Huang

A dual-functional sensor based on silver nanoparticles was synthesized by a two-stage procedure consisting of a low-temperature chitosan–Ag+ complexation followed by a high-temperature reduction of the complex to form chitosan-capped silver nanoparticles (CS-capped Ag NPs).


2013 ◽  
Vol 57 (10) ◽  
pp. 4945-4955 ◽  
Author(s):  
Divya Prakash Gnanadhas ◽  
Midhun Ben Thomas ◽  
Rony Thomas ◽  
Ashok M. Raichur ◽  
Dipshikha Chakravortty

ABSTRACTThe emergence of multidrug-resistant bacteria is a global threat for human society. There exist recorded data that silver was used as an antimicrobial agent by the ancient Greeks and Romans during the 8th century. Silver nanoparticles (AgNPs) are of potential interest because of their effective antibacterial and antiviral activities, with minimal cytotoxic effects on the cells. However, very few reports have shown the usage of AgNPs for antibacterial therapyin vivo. In this study, we deciphered the importance of the chosen methods for synthesis and capping of AgNPs for their improved activityin vivo. The interaction of AgNPs with serum albumin has a significant effect on their antibacterial activity. It was observed that uncapped AgNPs exhibited no antibacterial activity in the presence of serum proteins, due to the interaction with bovine serum albumin (BSA), which was confirmed by UV-Vis spectroscopy. However, capped AgNPs [with citrate or poly(vinylpyrrolidone)] exhibited antibacterial properties due to minimized interactions with serum proteins. The damage in the bacterial membrane was assessed by flow cytometry, which also showed that only capped AgNPs exhibited antibacterial properties, even in the presence of BSA. In order to understand thein vivorelevance of the antibacterial activities of different AgNPs, a murine salmonellosis model was used. It was conclusively proved that AgNPs capped with citrate or PVP exhibited significant antibacterial activitiesin vivoagainstSalmonellainfection compared to uncapped AgNPs. These results clearly demonstrate the importance of capping agents and the synthesis method for AgNPs in their use as antimicrobial agents for therapeutic purposes.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Vinod Vellora Thekkae Padil ◽  
Nhung H. A. Nguyen ◽  
Alena Ševců ◽  
Miroslav Černík

Gum karaya (GK), a natural hydrocolloid, was mixed with polyvinyl alcohol (PVA) at different weight ratios and electrospun to produce PVA/GK nanofibers. An 80 : 20 PVA/GK ratio produced the most suitable nanofiber for further testing. Silver nanoparticles (Ag-NPs) were synthesised through chemical reduction of AgNO3(at different concentrations) in the PVA/GK solution, the GK hydroxyl groups being oxidised to carbonyl groups, and Ag+cations reduced to metallic Ag-NPs. These PVA/GK/Ag solutions were then electrospun to produce nanofiber membranes containing Ag-NPs (Ag-MEMs). Membrane morphology and other characteristics were analysed using scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy, and UV-Vis and ATR-FTIR spectroscopy. The antibacterial activity of the Ag-NP solution and Ag-MEM was then investigated against Gram-negativeEscherichia coliandPseudomonas aeruginosaand Gram-positiveStaphylococcus aureus. Our results show that electrospun nanofiber membranes based on natural hydrocolloid, synthetic polymer, and Ag-NPs have many potential uses in medical applications, food packaging, and water treatment.


2021 ◽  
Vol 2 (1) ◽  
pp. 1-11
Author(s):  
Umme Ruman ◽  
Poonah Kia

Momordica charantia is a phenolic rich vegetable. In this study, the fruits and seeds extract of M. charantia were used to synthesize silver nanoparticles (Ag NPs) using biotechnological approach. Structural, morphological, and antimicrobial properties of the synthesized Ag-NPs were characterized using UV/Vis Spectrophotometry, Dynamic Light Scattering (DLS), High Resolution Transmission Electronics Microscopy (HRTEM), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray diffraction (XRD). In DLS, the average particle size of Ag-NPs was found 17.5 ± 2.1 nm and 18.3 ± 1.9 nm using seed and fruit extract, respectively. HRTEM has revealed their spherical structure for both seed and fruit extract of M. charantia. FESEM images found Ag-NPs with the size between ~20 and ~35 nm. The Ag NPs exhibited Surface Plasmon Resonance (SPR) centered at 405 nm for seed extract and 402 nm for fruit extract using a UV–visible spectrophotometer. FT-IR results showed phenolic and carbohydrate compounds involved in the synthesis of the Ag NPs. Furthermore, the synthesized Ag NPs has found highly rich in antibacterial properties against Escherichia coli and Pseudomonas aeruginosa bacterium. Thus, bioconversion of Ag NPs by M. charantia could be employed as a potential antibacterial source to eliminate pathogenic microorganisms from agricultural and food preservation industry.


Author(s):  
Karim Samy El-Said ◽  
Ahmed Ahmed El-Barbary ◽  
Hazem M. ElKholy ◽  
Ahmed S. Haidyrah ◽  
Mohamed Betiha ◽  
...  

Reaction of 2-mercapto-3-phenylquinazolin-4(3H)-one (MPQ) with both 4-vinyl benzyl chloride and allyl bromide furnished the reactive heterocyclic monomers 3-phenyl-2-((4-vinylbenzyl) thio) quinazolin-4(3H)-one (PVTQ) and 2-(allylthio)-3-phenylquinazolin-4(3H)-one (APQ), respectively. Copolymerization of PVTQ monomer with styrene and methyl methacrylate in the presence of 2,2′-azobisisobutyronitrile (AIBN) afforded the copolymers PS-co-PPVTQ and PMMA-co-PPVTQ, respectively. Similarly, copolymerization of monomer APQ with styrene and methyl methacrylate (MMA) afforded the copolymers PS-co-PAPQ and PMMA-co-PAPQ, respectively. The resulted copolymers were characterized by using FT-IR, 1H-NMR and GPC techniques. Silver nanocomposites of PS, PMMA, PS-co-PPVTQ, PMMA-co-PPVTQ, PS-co-PAPQ and PMMA-co-PAPQ were synthesized by the addition of silver nitrate into the polymer solution. The reduction of silver ions into silver nanoparticles was performed in DMF and water. Thermogravimetric (TGA) analysis was used to determine the thermal stability of the copolymers and their silver nanocomposites. The X-ray diffraction (XRD) analysis indicated the amorphous structures of the co-polymers and confirmed the formation of silver nanoparticles. The antitumor and antibacterial activities were screened for the copolymers and enhanced by the formation of their silver nanocomposites. In vivo antitumor activity in Ehrlich Ascitic Carcinoma (EAC) mice model showed that PS-co-PPVTQ/Ag NPs, PMMA-co-PPVTQ/Ag NPs, and PMMA-co-PAPQ/Ag NPs displayed promising inhibitory effects against EAC and induce apoptosis against MCF-7 cells.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4479
Author(s):  
Pei-Jun Li ◽  
Jiang-Juan Pan ◽  
Li-Jun Tao ◽  
Xia Li ◽  
Dong-Lin Su ◽  
...  

The present study focuses on the biological synthesis, characterization, and antibacterial activities of silver nanoparticles (AgNPs) using extracellular extracts of Aspergillus japonicus PJ01.The optimal conditions of the synthesis process were: 10 mL of extracellular extracts, 1 mL of AgNO3 (0.8 mol/L), 4 mL of NaOH solution (1.5 mol/L), 30 °C, and a reaction time of 1 min. The characterizations of AgNPs were tested by UV-visible spectrophotometry, zeta potential, scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric (TG) analyses. Fourier transform infrared spectroscopy (FTIR) analysis showed that Ag+ was reduced by the extracellular extracts, which consisted chiefly of soluble proteins and reducing sugars. In this work, AgNO3 concentration played an important role in the physicochemical properties and antibacterial properties of AgNPs. Under the AgNO3 concentration of 0.2 and 0.8 mol/L, the diameters of AgNPs were 3.8 ± 1.1 and 9.1 ± 2.9 nm, respectively. In addition, smaller-sized AgNPs showed higher antimicrobial properties, and the minimum inhibitory concentration (MIC) values against both E. coli and S. aureus were 0.32 mg/mL.


Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2112 ◽  
Author(s):  
Mudassir Iqbal ◽  
Hadia Zafar ◽  
Azhar Mahmood ◽  
Muhammad Bilal Khan Niazi ◽  
Muhammad Waqar Aslam

This research endeavor aims to develop polyvinyl alcohol (PVA) based films capable of blends with silver nanoparticles (Ag–NPs) for improved antibacterial properties and good mechanical strength to widen its scope in the field of wound dressing and bandages. This study reports synthesis of propylamine-substituted PVA (PA–PVA), Ag–NPs via chemical and green methods (starch capping) and their blended films in various proportions. Employment of starch-capped Ag–NPs as nanofillers into PVA films has substantially improved the above-mentioned properties in the ensuing nanocomposites. Synthesis of PA–PVA, starch-capped Ag–NPs and blended films were well corroborated with UV/Vis spectroscopy, FTIR, NMR, XRD and SEM analysis. Synthesized Ag–NPs were of particle shape and have an average size 20 nm and 40 nm via green and chemical synthesis, respectively. The successful blending of Ag–NPs was yielded up to five weight per weight into PA–PVA film as beyond this self-agglomeration of Ag–NPs was observed. Antibacterial assay has shown good antimicrobial activities by five weight per weight Ag–NPs(G)-encapsulated into PA–PVA blended film, i.e., 13 mm zone inhibition against Escherichia coli and 11 mm zone inhibition against Staphylococcus aureus. Physical strength was measured in the terms of young’s modulus via tensile stress–strain curves of blended films. The five weight per weight Ag–NPs(G)/PA–PVA blend film showed maximum tensile strength 168.2 MPa while three weight per weight Ag–NPs(G)/PVA blend film showed highest values for ultimate strain 297.0%. Ag–NPs embedment into PA–PVA was resulted in strong and ductile film blend than pristine PA–PVA film due to an increase in hydrogen bonding. These good results of five weight per weight Ag–NPs(G)/PA–PVA product make it a potent candidate for wound dressing application in physically active body areas.


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