Investigation of antibacterial properties silver nanoparticles prepared via green method

Chemistry Central Journal (Impact Factor: 2.19). 07/2012; 6(1):73. DOI: 10.1186/1752-153X-6-73
Source: PubMed


This study aims to investigate the influence of different stirring times on antibacterial activity of silver nanoparticles in polyethylene glycol (PEG) suspension. The silver nanoparticles (Ag-NPs) were prepared by green synthesis method using green agents, polyethylene glycol (PEG) under moderate temperature at different stirring times. Silver nitrate (AgNO3) was taken as the metal precursor while PEG was used as the solid support and polymeric stabilizer. The antibacterial activity of different sizes of nanosilver was investigated against Gram–positive [Staphylococcus aureus] and Gram–negative bacteria [Salmonella typhimurium SL1344] by the disk diffusion method using Müeller–Hinton Agar.

Formation of Ag-NPs was determined by UV–vis spectroscopy where surface plasmon absorption maxima can be observed at 412–437 nm from the UV–vis spectrum. The synthesized nanoparticles were also characterized by X-ray diffraction (XRD). The peaks in the XRD pattern confirmed that the Ag-NPs possessed a face-centered cubic and peaks of contaminated crystalline phases were unable to be located. Transmission electron microscopy (TEM) revealed that Ag-NPs synthesized were in spherical shape. The optimum stirring time to synthesize smallest particle size was 6 hours with mean diameter of 11.23 nm. Zeta potential results indicate that the stability of the Ag-NPs is increases at the 6 h stirring time of reaction. The Fourier transform infrared (FT-IR) spectrum suggested the complexation present between PEG and Ag-NPs. The Ag-NPs in PEG were effective against all bacteria tested. Higher antibacterial activity was observed for Ag-NPs with smaller size. These suggest that Ag-NPs can be employed as an effective bacteria inhibitor and can be applied in medical field.

Ag-NPs were successfully synthesized in PEG suspension under moderate temperature at different stirring times. The study clearly showed that the Ag-NPs with different stirring times exhibit inhibition towards the tested gram-positive and gram-negative bacteria.

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    • "The zeta potential parameter is important to determine the stability of Ag-NPs in the suspension. A minimum of ±30 mV zeta potential values is required to indicate a stable nano-suspension[36]. The zeta potential obtained for the CMSP-Ag-NPs synthesized at 1% CMSP of DS 0.8, 0.6 and 0.4 at pH 11, 50 kGy as depicted in the (Fig. 4B) was found to be -40.1 ± 1.5 mV, -36.2 ± 1.3 mV and -36.1 ± 1.4 mV respectively. "
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    • "Owing to the wide range of applications offered by nanoparticles in various fields, different approaches have been deliberated for their synthesis. Several methodologies were developed to obtain Ag NPs of wide ranging surface morphology including, biosynthesis (Vankar and Shukla 2012; Christensen et al. 2011, Shanmugavadivu et al. 2014), microwave processing (Pal et al. 2013), laser ablation (Amendola et al. 2012), gamma irradiation (Gasaymeh et al. 2010), electron irradiation (Misra et al. 2013), electrodeposition (Khaydarov et al. 2008; Sanchez et al. 2000; Roldan et al. 2013), green synthesis (Shameli et al. 2012; Pandey et al. 2012; Ahmad and Sharma 2012), sonoelectrochemical synthesis (Socol et al. 2002); chemical reduction (Sileikaite et al. 2009), photochemical method (Kutsenko and Granchak 2009), thermal decomposition, radiolytic reduction (Saion et al. 2013) etc., Among these techniques, bottom-up methods are frequently adopted for the synthesis of Ag NPs, since they offer easy and expedient route for the synthesis of Ag NPs. Among them electrochemical method is the most popular and frequently used method for the Ag NPs synthesis. "
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