Antimicrobial Properties of Silver Nanoparticles and Their Industrial Application in the Present Scenario of AMR
Basant1, and Parma Ram Gorachiya2
1PhD scholar, Division of Veterinary Biotechnology, ICAR- Indian Veterinary Research Institute, Bareilly, UP, India
2PhD, Department of Livestock Products Technology, College of Veterinary and Animal Science, RAJUVAS, Bikaner, Rajasthan
Corresponding Author: basantgodara08@gmail.com
Abstract-
In the present scenario, the whole world is facing the problem of antimicrobial resistance (AMR) which is continuously increasing day by day. The antimicrobial properties of silver are very well known from ancient times. Advances in nanotechnology provided a new direction to use the antimicrobial properties of silver in various fields. Lower toxicity and easy to synthesize properties of silver nanoparticles make them the most versatile among all metallic nanoparticles.
Keywords– Antimicrobial resistance (AMR), Silver nanoparticles (AgNPs)
Introduction-
Silver is well-known metal to exhibits a strong antimicrobial activity in all forms (Franci et al., 2015). Silver and silver ions have been used for their bactericidal properties for thousands of years (Jain et al., 2009). Silver nanoparticles (AgNPs) are considered versatile and fascinating among all the metallic nanoparticles so they have gained increasing attention from researchers. AgNPs possess potent antibacterial activity and are also used as an anti-fungal, anti-inflammatory, and anti-viral agent. Based on research done so far, the AgNPs may be engineered in order to increase their stability, efficacy, specificity, and biocompatibility. Novel properties of any nanoparticles are mainly dependent on their shape, size, and morphology and all these characteristics mainly depend on the method of preparation, concentration, and strength of the reducing agent, nature of the solvent, and temperature so that every step of their synthesis is crucial and important in itself (Siddiqi et al., 2018).
As no great success has been achieved in the discovery of new antibiotics in the last decade but the most common approach is to use a combination of antibiotics or antibiotics with some plant extract or other compounds is going on to find a solution to combat AMR or can say multidrug resistance. A common term “synergism” is used in this antibacterial context which can be defined as the combined inhibitory effect of the two drugs being greater than that of the expected normal addition (Baym et al., 2016). A number of combinations with already existing antibiotics and some newer compounds have been tried to achieve some effective solutions for treating MDR pathogen-associated infections (Tangden, 2014) and so many others have to discover.
Mechanism of action of AgNPs against bacteria-
The nanoparticles are being considered as an alternative to antibiotics primarily because of the effective prevention of microbial drug resistance in certain cases. The unregulated and misuse of antibiotics pushed us towards numerous global health hazards problem of antimicrobial resistance (AMR). There are some different proposed mechanisms of action of AgNPs which involves direct adhesion of fine particles of AgNPs on the cell wall resulting in changes in the cell wall which disable the function of the cell wall to protect internal parts of the cell and ultimately killing of the organism (Wong and Liu, 2010). The second proposed mechanism states that AgNPs not only interact and accumulate on cell wall but also are capable to penetrate the cell and interact with DNA thus changes in DNA retards the normal functioning of the cell and lead to cell death (Reidy et al., 2013) another reported mode of action of AgNPs on bacterial cells suggests the interaction of Ag+ ions with sulfur-containing proteins of the cell wall of bacterium leads to improper functioning of the cell wall (UI-Islam et al., 2014).
Different methods for synthesis of silver nanoparticles
- A) Chemical method- The most common and most preferable method of making AgNPs (Yu and Zhou, 2013). This method mainly includes chemical reductions of silver salts in aqueous solutions to obtain surfactant stabilized silver nanoparticles (Yin et al., 2002).
- B) Physical method- usually in these methods some adaptive techniques like evaporation and condensation processes are implemented by use of some electric discharge machining. These methods provide the advantage of gaining very specific and small-sized particles even of less than 10nm size (Lee and Kang et al., 2004).
- C) Photochemical method- as the name indicates these methods employ the use of light and chemicals simultaneously in the preparation method. AgNPs from these methods are obtained by photoreduction of silver ions with help of photochemically activated intermediates such as radicals (Christy and Umadevi, 2012).
- D) Biological synthesis- this is a modern and attention fetching method as the name suggest some biomolecules are incorporated in the preparatory method. Mainly some plant leaves and microbes are used. In biological method three main components are employed a) Ag precursor, b) Reducing agent, and c) Stabilizer. Here biomolecules act as reducing agents and stabilizers. By using various plant leaves and yeast species AgNPs have been synthesized for different uses. Biosynthesized AgNPs are mainly recognized for their potent antimicrobial activity which is because of their highly variable size and geometry (Venkata and Savithrama, 2013).
Applications of AgNPs-
Previously silver is known for making ornaments and coins etc. and its antimicrobial property was also known so many years ago but with the development of nanotechnology and other advancements, silver nanoparticles have come in limelight. AgNPs are the most famous and versatile among all metallic nanoparticles. These are widely used at an industrial scale in the production of daily used commercial products due to having electrical, thermal, and antimicrobial properties. The main application area of AgNPs is in medical science. The AgNPs have become the choice of ingredients in the manufacturing of various medical and surgical products due to their broad-spectrum antimicrobial. It is widely used in large-scale manufacturing of medical devices and instruments non-toxic, infection and contamination-free also (Roe et al., 2008) such as catheters and several other instruments as well as in various topical preparations, especially in ointments and gels used for treating infectious or burn wound. An AgNPs containing gel formulation has been prepared for topical use which has been given the name S-gel showed potent antibacterial activity in vitro as well as in vivo (Jain et al., 2009). Another vast area of AgNPs use is in the textile industry where AgNPs are widely incorporated for making functionalized fabricated material previously it was limited up to the making of surgical suits but now this is widely used in the manufacturing of socks, T-shirts and sportswear also (Benn et al., 2008 and Blasser et al., 2008). AgNPs are also widely used in the food industry as a preservative (Cushen et al., 2012). It can be easily said that the use of silver nanoparticles as an antimicrobial is not only limited to the therapeutic industry it is also widely used in various other commercial products.
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5317269/