This study reports the extracellular synthesis of silver nanoparticles by Rhizopus stolonifer and its efficacy against multidrug resistant (MDR) E.coli and S.aureus isolated from Khwaja Bande Nawas Hospital, Gulbarga, Karnataka. Synthesis of silver nanoparticles (AgNPs) was carried out by using fungal filtrate of R.stolonifer and an aqueous solution of AgNO3. The characterization of AgNPs was made by UV-Visible absorption Spectroscope, Scanning Electron Microscope and Energy Dispersed Spectroscope (SEM-EDS), Transmission Electron Microscope (TEM), Fourier Transform Infrared (FTIR) spectroscopy and Atomic Force Microscope (AFM). TEM micrograph revealed the formation of spherical nanoparticles with size ranging between 3 to 20 nm. Atomic force microscopy gives the three dimensional structure of the particles. The presence of proteins was detected by FTIR spectroscopy. Three dimensional structure of AgNPs was studied by AFM. AgNPs produced by R.stolonifer gave good antibacterial activity against clinical isolates which were multidrug resistant. Here we report the efficacy of mycogenic metal nanosilver against MDR strains which is difficult through conventional chemotherapy.
Table of Contents
1. Introduction
2. Materials and Methods
2.1. Biosynthesis of silver nanoparticles
2.2. Characterization of silver nanoparticles
2.3. Source of microorganisms
2.4. Analysis of the Antibacterial activity of silver nanoparticles
3. Result
4. Discussion
4.1. UV-Visible absorption Spectroscopy
4.2. SEM-EDS
4.3. Transmission electron microscopy
4.4. Fourier Transform Infrared spectroscopy
4.5. Atomic force microscope
4.6. The antibacterial activity of silver nanoparticles
Research Objectives and Core Themes
This study aims to evaluate the extracellular synthesis of silver nanoparticles using the fungus Rhizopus stolonifer and to assess their antibacterial efficacy against clinical multidrug-resistant (MDR) strains of Escherichia coli and Staphylococcus aureus.
- Biological synthesis of metallic silver nanoparticles via fungal filtrate.
- Comprehensive characterization using UV-Visible, SEM-EDS, TEM, FTIR, and AFM techniques.
- Assessment of antimicrobial properties against multidrug-resistant bacterial strains.
- Evaluation of the stability and morphological characteristics of biosynthesized nanoparticles.
- Exploration of eco-friendly, cost-effective, and toxicity-free production alternatives.
Excerpt from the Book
1. Introduction
Nanotechnology is the ability to observe, measure, manipulate and manufacture things at the nanometre scale. A nanometre (nm) is a unit of length 10-9, or a distance of one-billionth of a meter. That’s very small. At this scale you are talking about the size of the atoms and molecules. Recently, scientist has endeavoured the use of microorganisms as possible eco-friendly nano factories for the synthesis of metallic nanoparticles [1]. An important aspect of nanotechnology is the development of toxicity-free synthesis of metal nanoparticles which is a great challenge. Where as chemical synthesis of nanoparticles have adverse effect due to the absorbance of toxic chemicals on the surface. Green synthesis provides advancements over chemical and physical methods as it is environment friendly, cost effective, easily scaled up for large scale synthesis and biological method does not require high pressure, energy and toxic chemicals.
New multidrug resistant strains of bacteria have become a serious problem in public health. The emerging resistances in bacteria and high cost of advanced antimicrobial drugs have encouraged researchers to search for effective and economically viable broadly applicable drugs [2]. It has been known for long time that silver ions are highly toxic to a wide range of bacteria and silver based compounds have been used extensively in bactericidal applications. Silver has one advantage of having broad antimicrobial activities against gram negative and gram positive bacteria. AgNPs are the most effective preparation of silver because of the high surface/volume fraction resulting in a large proportion of silver atoms in direct contact with their environment [2]. It can be expected that the high specific surface area and high fraction of surface atoms of AgNPs will lead to high antimicrobial activity compared to bulk Ag metal [3]. The purpose of this study was to examine the antibacterial activity of silver nanoparticles against multidrug resistant S.aureus and E.coli.
Summary of Chapters
1. Introduction: This chapter defines nanotechnology and explores the need for environmentally friendly, biological synthesis methods for silver nanoparticles to combat multidrug-resistant bacterial strains.
2. Materials and Methods: This section details the protocol for fungal cultivation, the biosynthesis process using Rhizopus stolonifer, and the analytical techniques employed for nanoparticle characterization and antibacterial testing.
3. Result: This chapter presents the visual evidence of silver nanoparticle formation through color change and confirms structural details via spectroscopy and microscopic analysis.
4. Discussion: This chapter interprets the experimental data, validating the size, stability, and antibacterial effectiveness of the synthesized silver nanoparticles against clinical pathogens.
Keywords
Rhizopus stolonifer, silver nanoparticles, MDR-strains, Escherichia coli, Staphylococcus aureus, nanometre scale, green synthesis, bactericidal, antimicrobial activity, fungal filtrate, biosynthesis, extracellular synthesis, surface plasmon resonance, characterization, clinical isolates.
Frequently Asked Questions
What is the core focus of this research study?
The study focuses on the extracellular biosynthesis of silver nanoparticles using the fungus Rhizopus stolonifer and their subsequent application as antibacterial agents.
What are the primary themes discussed in the paper?
Key themes include green nanotechnology, mycogenic synthesis of silver, characterization of nanomaterials, and the antimicrobial potential against multidrug-resistant bacteria.
What is the main research objective?
The primary goal is to synthesize silver nanoparticles using R. stolonifer and to examine their antibacterial efficacy against MDR strains of E. coli and S. aureus isolated from clinical settings.
Which scientific methods were employed for analysis?
The researchers utilized various methods, including UV-Visible absorption spectroscopy, SEM-EDS, TEM, FTIR spectroscopy, and Atomic Force Microscopy (AFM) to verify the synthesis and properties of the particles.
What topics are covered in the main body of the paper?
The main body covers the preparation of fungal biomass, the chemical reduction process, the analytical characterization of the particles, and experimental trials to determine the Minimum Inhibitory Concentration (MIC) against pathogens.
Which keywords characterize this work?
The work is characterized by terms such as silver nanoparticles, Rhizopus stolonifer, MDR-strains, green synthesis, and antimicrobial activity.
Why was Rhizopus stolonifer chosen for this experiment?
The choice was driven by the goal of finding an eco-friendly, cost-effective, and safe biological "factory" for synthesizing metallic nanoparticles that avoids the toxic chemicals associated with traditional chemical synthesis.
How stable are the nanoparticles produced by this method?
The study found that the biosynthesized silver nanoparticles were highly stable, showing minimal agglomeration even after six months of storage due to the protective coating of capping proteins.
What did the AFM analysis reveal about the nanoparticles?
The AFM study provided a three-dimensional view, confirming the particles were spherical with a smooth surface and monodispersed in nature.
How does the size of the nanoparticles relate to their antibacterial effectiveness?
Smaller particles provide a larger surface-to-volume ratio, which enhances their interaction with bacterial cell walls and increases their bactericidal potency against multidrug-resistant strains.
- Quote paper
- Afreen Banu (Author), Vandana Rathod (Author), E. Ranganath (Author), 2011, Synthesis and characterization of silver nanoparticles by "Rhizopus stolonifer" and its activity against multidrug resistant "Escherichia coli" and "Staphylococcus aureus", Munich, GRIN Verlag, https://www.grin.com/document/192147
