Antibacterial Activities and effects of Silver Nanoparticles

 

Maytham M. Alabassi

Department of Ecology, Faculty of Science, University of Kufa, Najaf, Iraq

 

ABSTRACT:

Background: In this study, the silver nanoparticles AgNPs were produced using Nd-YAG laser of silver nitrate. It was known for quite some time now that AgNPs can inhibit microbial growth and even kill microbes. Methods: UV-VIS and Electron Microscope were characterized the AgNPs. Results: The electron microscopic images showed that the particles were spherical. The antibacterial activity was evident from the zone of inhibition. The AgNPs at 8mM better than the 6 mM as an antibacterial for both types of bacteria. The data proving that AgNPs prepared using the laser suitable for the formulation of new kinds of bactericidal material in the different sciences. Conclusions: It concluded that the nanoparticles are bactericidal at high concentration. So AgNPs are believed to act as preventive of bacterial contamination.

 

 

 

INTRODUCTION:

Disease-causing microbes become resistant to drug treatment are a growing public health problem. Many studies are now developing new antimicrobial with the emergence of microbial organisms’ resistant to multiple antibiotics. Silver has been used for years in the medical applications as antimicrobial in burn treatment, elimination of microorganisms, disinfection in water treatment, prevention of bacteria on catheters [1-4]. Nanosilver was less reactive than silver ions, which is suitable for medical applications. AgNPs are attractive as antimicrobials due to the worldwide crisis of bacterial resistance to conventional, narrow-target antibiotics [5].

 

AgNPs are synthesized using various physical, biological and chemical pathways [6]. Pulsed laser ablation (PLA) is a physical approach that permits preparation of stable metal colloids in pure solvents without the use of capping or stabilizing agents [7].

 

 

This method is possible to isolate the effect of Ag on living cells (bacteria) from other compounds. Morones et al. studied the effect of 1–100 nm AgNPs on Gram-negative bacteria using HR-TEM analysis, where the bacterial growth inhibition was found to be more efficient by AgNPs with a diameter of about 10 nm [8].   

 

AgNPs were characterized and tested for antimicrobial activity against Klebsiella and Staphylococcus as references for Gram-negative and Gram-positive bacteria, respectively. K. pneumoniae has the gram-negative, lactose fermenting, non-motile, rod-shaped organism. It can grow either with or without O₂, are surrounded by a capsule, which increases the virulence by acting as a physical barrier to the immune response. It found in the skin, mouth, intestinal tract,and human stool. It is leading to pneumonia, wound infections, urinary tract infections, bloodstream infections, and meningitis [9, 10]. When these bacteria get into other areas of the body, they can cause disease. In this study have been investigated the antimicrobial effects of silver nanoparticles (SNPs) prepared using Nd-YAG laser system.

 

MATERIALS AND METHODS:

An aqueous solution of silver nitrate (AgNO₃) at 6 and 8 mM concentrations were prepared. The silver nanoparticles (AgNPs) were prepared using Nd-YAG laser system. The silver solution was exposed to PLA. The Nd-YAG laser beam focused on the AgNO₃ into the container of 2 mL.

 

The q-switched Nd-YAG laser system has pulses of 532 nm to 1064 nm wavelength with the energy of 700 mJ of 10 ns and 30 pulses at 19^o to 23^o. The silver solution color within few minutes was changed. The absorbance spectra of NPs solution were measured using a Shimadzu spectrophotometer (200 nm 1100 nm). All the spectra exhibit a characteristic peak at 400 nm, indicating the formation of a silver solution. The silver nanoparticles with different diameters were synthesized using a laser. The two concentrations of AgNPs, as obtained by laser, were used for the antibacterial tests against bacteria samples (Klebsiella and Staphylococcus) were collected from the hospitals in Najaf city, Iraq.

 

RESULTS AND DISCUSSION:

Table 1 shows the inhibition zones of bacterial colonies obtained by treating bacterial using AgNps. The results are shown in Table 1.

 

Table 1 Bacteria types with the concentration

Bacteria type	Concentration (mM)	Inhibition zone (cm)
Klebsiella	6	2.3
Staphylococcus	6	4.5
Klebsiella	8	2.5
Staphylococcus	8	3.4
Klebsiella	6	1.7

The concentration of AgNps of about six mM has the inhibition zone of 1.7-2.3 cm, whereas the level of AgNps of about 8 mM had the inhibition zone of 2.5 cm when it was added to Klebsiella bacteria. The concentration of AgNps of about six mM has the inhibition zone of approximately 4.5 cm, whereas the AgNps of about 8 mM had the inhibition zone of 3.4 cm when it added to Staphylococcus bacteria. These results were shown that the nanoparticles concentration of about 8 mM was better than the nanoparticles concentration of 6 mM as an antibacterial for both types.

 

 

Fig. 1  Electron microscopy images of the AgNPs

 

 

Fig. 2 Antibacterial activity of AgNP (a. The middle of the agar plate is for the blank test, having no AgNP; b. No AgNP; c and d. Antibacterial activity of AgNP having different concentrations (6 and 8 mM))

With these nanoparticles, a preliminary test for antibacterial carried out using cup diffusion method and the effects of AgNPs on bacterial growth has studied using employing Minimum Inhibitory Concentration (MIC) method. Results obtained prove that AgNPs prepared by the Nd-YAG laser method was suitable for the formulation of new types of bactericidal materials. The AgNPs were spherical, which was confirmed by the electron microscopy, as shown in Fig. 1. The number of laser pulses and energy of was 30 and 700 mJ, respectively. The peak in spectra of silver showed the maximum absorption was 450 nm, which is indicated the AgNPs. UV-VIS confirmed the formation of nanoparticles using liquid Q-switched Nd-YAG laser.

The antibacterial activities of AgNPs were proved of the zone of inhibition, as shown in Fig. 2. No zones of inhibition were found in the vehicle control well (the middle of the plate) which suggested that the antimicrobial activities were explicitly due to AgNPs.

 

CONCLUSIONS:

The effects of AgNPson bacterial growth has studied by Minimum Inhibitory Concentration (MIC) case. The results showed that the AgNPs concentration at 8mM was better than theAgNPsconcentration of 6 mM as an antibacterial for both types. Results were proving that AgNPs prepared using the Nd-YAG laser was suitable for the formulation of new kinds of bactericidal material in the different sciences.

 

ACKNOWLEDGEMENT:

The author acknowledges the financial support of the University of Kufa, Iraq. The author is grateful to Dr. Basim A. Almayahi, Department of Ecology, College of Science, University of Kufa (basimnajaf@yahoo.com) for assisting me throughout conducting the present research.

 

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Accepted on 29.04.2018          © RJPT All right reserved

Research J. Pharm. and Tech 2018; 11(9): 4126-4128.