Enhanced catalytic and antibacterial activities of silver nanoparticles immobilized on poly(N-vinyl pyrrolidone)-grafted graphene oxide

RSC Advances ◽  
2015 ◽  
Vol 5 (100) ◽  
pp. 81994-82004 ◽  
Author(s):  
Shikha Singh ◽  
Ravi Kumar Gundampati ◽  
Kheyanath Mitra ◽  
K. Ramesh ◽  
Medicherla V. Jagannadham ◽  
...  

PNVP grafted on GO regulates the size of Ag nanoparticles and enhances the catalytic and antibacterial properties along with increase in the dispersibility of GO.

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.


RSC Advances ◽  
2020 ◽  
Vol 10 (68) ◽  
pp. 41600-41611
Author(s):  
A. Farouk ◽  
S. El-Sayed Saeed ◽  
S. Sharaf ◽  
M. M. Abd El-Hady

Silver nanoparticles were in situ prepared on the surface of linen fabric coated by graphene oxide (GO).


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
R. Mahendran ◽  
D. Sridharan ◽  
K. Santhakumar ◽  
T. A. Selvakumar ◽  
P. Rajasekar ◽  
...  

The incorporation of carbonaceous nanofillers into polymers can result in significant materials with improved physicochemical properties and novel composite functionalities. In this study, we have fabricated antibacterial, lightweight, transparent, and flexible graphene oxide (GO) reinforced polycarbonate thin films by a facile and low-cost methodology. Solution blending is employed to get a homogeneous mixture of PC-GO composites at various loading of GO, and the thin films are prepared by dry-wet phase inversion technique. Thermal studies and micrographs of the films revealed the incorporation of GO in PC matrix. Microstructure of the thin films showed the homogeneous dispersion of GO at micro- and nanoscales; however, at higher loading of GO (0.7%), significant agglomeration is observed. More importantly, PC-GO composite films exhibited excellent antibacterial activities against E. coli and S. aureus, owing to the antibacterial nature of GO nanoparticles.


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.


Author(s):  
Imad H. Khaleel ◽  
Abdulkareem A. Alkhafaji ◽  
Hussein A. Miran ◽  
Zainab N. Jaf

In this research, a novel thin film Si-GO10 and nano-powders Si-GO30 of silica-graphene oxide composite were prepared via sol-gel method and deposited on glass substrates using spray pyrolysis. XRD results showed a relatively strong peak in graphite layer that corresponds to the plane of (002). TEM images displayed that SiO<sub>2</sub> nano-particles were randomly distributed on the surface of Si-GO30 sample, and the particle size in these nano-powders was below 50 nm. Moreover, silica nano-particles on the surface of GO plates exhibited almost a spherical and rod-like nanoparticles shapes, which in turn confirmed the formation of SiO<sub>2</sub>-GO nano-hybrids. FESEM analysis reveals a different morphology, the Si-GO10 sample is so rough and crumble, while the Si-GO30 sample is relatively smooth on the surface. Photocatalytic investigations revealed the composite materials exhibit high activity for dye adsorption and decomposition. Si-GO10 thin film did not undergo degradation after 120 minutes, however, for Si-GO30 nano-powder, the adsorption peak intensity was reduced to 665 nm, indicating a decrease in the dye concentration in the solution. FTIR analysis demonstrated that carboxylic functional groups are decreased by increasing silica particles. Photo-Luminescence (PL) spectrum in Si-GO10 thin film disclosed a severe emission peak at about 675 nm. This spectrum was completely disappeared in Si-GO30 nano-powders. Results of the antibacterial properties emphasized that Si-GO30 nano-particle would prevent Escherichia. coli growth after 20 hours. The presented methodology allows for the synthesis of graphene oxide supported silicon dioxide nano-particles for promising applications in photocatalytic and antibacterial fields.


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.


Nano Express ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 010041
Author(s):  
Hui Wang ◽  
Yalei Zhang ◽  
Xiaobing Xu ◽  
Feiyao Yang ◽  
Ke Li ◽  
...  

RSC Advances ◽  
2016 ◽  
Vol 6 (11) ◽  
pp. 8763-8772 ◽  
Author(s):  
Xu Wang ◽  
Peng Lu ◽  
Yuan Li ◽  
Huining Xiao ◽  
Xiangyang Liu

The antibacterial properties and mechanism of three types of graphene derivatives, graphene oxide (GO), fluorinated graphene (FG), and guanidine-modified graphene (PHGH-G), were comparatively studied.


2019 ◽  
Vol 10 (3) ◽  
pp. 5592-5598

A new green deposition of silver nanoparticles (AgNPs) on polymers was proposed in this work. In-situ synthesis of AgNPs on polymers was achieved via a green procedure using natural reducing agents, which are Ageratum conyzoidez and Mikania micrantha. Several characterizations of the treated polymers such as color transformation, surface morphology, elemental contents, and water absorption were comprehensively evaluated. For the application, the treated polymers were then tested against waterborne bacteria, which are Escherichia coli and Bacillus cereus. Rapid deposition of AgNPs via the presently biological method can be successfully achieved as observed via surface morphology analysis and energy dispersive X-ray investigation. Water absorption capabilities of the polymers can be decreased after attaching with AgNPs, which can also probably contribute to the enhancement of their antibacterial activities. This study observed that the treated polymers showed excellent antibacterial activities against Escherichia coli and Bacillus cereus. The findings of this study are useful in designing water purifiers to disinfect contaminated water.


2018 ◽  
Vol 28 (2) ◽  
pp. 179 ◽  
Author(s):  
Ngo Vo Ke Thanh ◽  
Huynh Trong Phat ◽  
Nguyen Thi Kim Anh ◽  
Nguyen Dang Giang ◽  
Lam Quang Vinh

Metallic nanoparticles as antibacterial agents have been studied for several years. The most used antibacterial nanoparticles are silver nanoparticles. The mechanisms and  antibacterial properties of silver nanoparticles are well known, but the effects of gold nanoparticles, especially gold Nano bipyramids, are not considered. In this research, we synthesized gold nanobipyramids (NBPs) by seed mediated method using surfactant cetyltrimethylammonium bromide (CTAB). After preparing, gold nanobipyramids is removed CTAB and modified the surface using polyethylene glycol, polyvinyl alcohol and chitosan as the stabilizers. Besides, antibacterial effects of gold nanobipyramids on both Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) are investigated in this paper. The results show that gold nanobipyramids have good antibacterial activities even at low concentration. The optimal concentration of stabilizers and gold nanobipyramids in antibacterial activities are also studied in this paper.


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