Industrial Chemistry
Open Access

Ecological poisonousness; Phyto-synthetic; Bioactivity; Modern application

Introduction

The subject of the current review is the gradual shift in the synthesis of nano silver from toxic physical and chemical methods to eco-friendly, cost-effective, and green methods that make use of biological resources. The silver nanoparticle, dubbed "one of the most commercially exploded metallic nanoparticles," and its synthesis are the subject of a comprehensive literature review in this article. its gradual shift toward an environmentally friendly synthesis approach; characterization and process optimization for improved bioactivity, as well as its commercial and industrial use. Nanoparticles can be ready by three methods viz. green, chemical, and physical methods in addition, the majority of the time, physical and chemical methods are toxic and hazardous , necessitating purification because of this. The growing demand for nanoparticles in applied science, including medicine, cannot be overlooked considering this toxic and hazardous issue. Green synthesis of nanoparticles using naturally occurring reagents like sugars, vitamins, plant extract, biodegradable polymers, microorganisms, and so on could address this issue. as lessening and covering specialists . Plant extracts have emerged as a significant player in the field of reducing and capping agents due to their low cost and easy availability . Green technology's environmentally friendly nanoparticles are widely used in a variety of commercial sectors, including the food, chemical, and cosmetic industries . The most frequently utilized metals in the green synthesis of nanoparticles are copper, palladium, silver, aluminum, gold, zinc, iron, titanium, and palladium . Silver nanoparticles have risen to the top of the list of metals used in green synthesis due to their extensive action history, which includes high electrical conductivity, chemical stability, catalytic activity, and broadspectrum antimicrobial activity [1] . Silver nanoparticles have also been used in water filtration membranes and water treatment . The pH, temperature, pressure, reaction time, particle size, pore size, dispersion, and optical dynamics are just a few of the many physical, chemical, and environmental parameters that influence silver nanoparticle bioactivity . Therefore, in addition to toxicity, the physiochemical properties of synthesized silver nanoparticles play a significant role in determining their usefulness in the industrial, medicinal, agricultural, and environmental sectors. This review therefore focuses on the fundamental understanding of nanoparticles, with an emphasis on the silver form, as well as their various synthesis methods and gradual shift toward an eco-friendly green synthesis approach for possible toxicity removal. Current concentrate additionally manages different cycle improvement strategies and their approval through instrumental investigation that will be fruitful with respect to biogenic and modern application [2].

Types of nanoparticles Based on their origin, nanoparticles can be divided into two categories: both without and with engineering . Nanoparticles which are gotten from normal occasions like disintegration, backwoods fire, storm and volcanic episode are known as non-designed nanoparticles. Engineered nanoparticles, on the other hand, are composed of a variety of materials, including metals (Ni, Au, Cu, Zn, Fe, and Ag) , non-metals (silica] , metal oxides (SiO2, CeO2, TiO2, Fe2O4, and Al2O3), lipids like stearic acid , and carbon (fullerene and graphene). Cellular drug delivery has made extensive use of inorganic non-materials.

There are four oxidation states in which silver and its nanoform, Ag (Silver), exist: Ag0, Ag+, Ag2+, and Ag3+, the latter two of which are abundant while the former two are unstable in water . Silver is insoluble in water if it exists in metallic form, but its metallic salts-silver chloride and silver nitrate-can be dissolved in water.

Types of nanoparticles

Based on creation aspect nanoparticles are of two types viz. nonengineered and engineered. Nanoparticles which are derived from natural events like erosion, forest fire, storm and volcanic incident are known as non-engineered nanoparticles. On the other hand, the nanoparticles that are man made from variety of materials like metals (Ni, Au, Cu, Zn, Fe and Ag) , non-metals (silica) , metal oxides (SiO2, CeO2, TiO2, Fe2O4 and Al2O3), lipids like stearic acid and carbon (fullerene and graphene) are known as engineered nanoparticles. Inorganic non-materials have been extensively used for cellular drug delivery [3].

Silver and its nano form

Ag (Silver) exist in four oxidation state viz. Ag0, Ag+, Ag2+ and Ag3+ of which former two are abundant and the remaining two are unstable in aquatic condition . Silver if present in metallic form are insoluble in water, but its metallic salts (silver chloride and silver nitrate) are soluble in water.

Methods for nanoparticle synthesis

A large number of techniques viz. laser ablation, gamma and electron irradiation, photochemical methods, microwave processing, chemical reduction, and biological synthetic methods has been reported for the synthesis of metallic nanoparticles. There are two broad line methods for nanoparticle synthesis viz. top-down method and bottomup method . In top-down method large size molecules are broken down into small size molecules which further undergone transformation into particles of nano dimension. Top-down method was often considered as destructive method of nano synthesis [4].

Physical methods of nanoparticles synthesis involve the use of various physical phenomena and techniques to produce nanoparticles with controlled size, shape, and composition. These methods are commonly employed in both research and industrial settings and offer advantages such as scalability, reproducibility, and precise control over nanoparticle properties.

Here are some prominent physical methods of nanoparticles synthesis:

Chemical vapor deposition (CVD): CVD is a widely used technique for synthesizing nanoparticles, especially thin films and nanowires. It involves the reaction of precursor gases in a controlled environment, leading to the deposition of nanoparticles on a substrate [5]. The precursor gases are typically introduced into a reaction chamber, where they undergo chemical reactions and condense as nanoparticles on a heated substrate.

Physical vapor deposition (PVD): PVD methods, such as evaporation and sputtering, involve the physical deposition of material onto a substrate to form nanoparticles. In evaporation, the material is heated to its vaporization point, and the resulting vapor condenses on a cool substrate, forming nanoparticles. Sputtering involves bombarding a target material with high-energy ions, causing atoms to be ejected and deposited on a substrate as nanoparticles.

Laser ablation: Laser ablation is a technique where a high-intensity laser beam is focused on a target material, causing its surface to vaporize and form a plasma plume [6-10]. This plume contains nanoparticles, which can be collected on a substrate or in a liquid medium. Laser ablation is particularly useful for synthesizing metal nanoparticles and their alloys.

Arc discharge: In arc discharge, a high-current electric arc is created between two electrodes, typically made of the material to be synthesized into nanoparticles. The arc vaporizes the electrode material, and the resulting plasma rapidly cools and condenses into nanoparticles. This method is commonly used for producing carbon-based nanoparticles, such as carbon nanotubes and fullerenes.

Sol-gel method: The sol-gel method involves the synthesis of nanoparticles from a solution (sol) that undergoes a gelation process to form a solid network (gel). The precursor materials are dissolved in a solvent, and subsequent hydrolysis and condensation reactions lead to the formation of nanoparticles within the gel matrix. This method offers excellent control over nanoparticle size and composition.

These are just a few examples of physical methods used for nanoparticles synthesis. Each method has its advantages and limitations, and the choice of method depends on the desired nanoparticle properties and the specific application requirements. Researchers and scientists continue to explore and develop new physical methods to expand the range of nanoparticle synthesis techniques.

Conclusion

Green chemistry-inspired formation of bioactive stable colloidal nano silver represents a significant advancement in the field of nanotechnology. This innovative approach combines the principles of green chemistry with the synthesis of nano silver, resulting in environmentally friendly and sustainable methods for producing nanoparticles with excellent stability and bioactivity. By utilizing green chemistry principles, such as the use of non-toxic precursors and solvents, renewable energy sources, and waste reduction, the synthesis of colloidal nano silver becomes more eco-friendly and less harmful to human health and the environment. This approach addresses the concerns associated with traditional methods that often involve hazardous chemicals and generate harmful byproducts. Furthermore, the bioactive nature of the stable colloidal nano silver offers immense potential for a wide range of applications. Its broad-spectrum antimicrobial activity makes it a promising candidate for combating various pathogens, including bacteria, viruses, and fungi. Additionally, its unique physicochemical properties, such as high surface area to volume ratio and tunable size, allow for enhanced reactivity and interaction with biological systems, making it highly attractive for biomedical and pharmaceutical applications . The wide-spectrum activity of bioactive stable colloidal nano silver offers new possibilities in areas such as wound healing, drug delivery, water treatment, and antimicrobial coatings. Its potential to address antibiotic resistance, minimize the use of harmful chemicals, and provide effective and sustainable solutions to various challenges is a significant breakthrough in nanotechnology. However, it is important to continue research and development in this field to fully understand the behavior, toxicity, and long-term effects of colloidal nano silver . Ensuring responsible manufacturing, handling, and disposal practices will be crucial in harnessing the benefits of this technology while minimizing any potential risks. Green chemistry-inspired formation of bioactive stable colloidal nano silver opens up a new era in nanotechnology, offering environmentally friendly synthesis methods and wide-spectrum bioactivity. This advancement has the potential to revolutioopensious industries and contribute to a more sustainable and healthier future.

1. Seyda R , Ravetkar AS, Shirote PJ (2011) Uv Spectrophotometric Estimation of  Rosuvastatin Calcium And Fenofibrate In Bulk Drug And Dosage Form Using Simultaneous Equation Method. Int J Chemtech Res 3:630-635.

Indexed at, Google Scholar

2.    Narayankar M, Sakpal PH, Bhingare CL, Ingale PL (2015) Development and Validation of Rp-Hplc Method For The Estimation Of Rosuvastatin Calcium And Niacin In Combined Tablet Dosage Form. Int J Pharma Res Rev 4:44-50.

Indexed at, Google Scholar

3. Donthula S, Kumar MK ,Teja GS, Kumar YM, Yasodha K ,et al. (2011)  A New Validated Rp-Hplc Method for Determination of Rosuvastatin Calcium In Bulk And Pharmaceutical Dosage Form. Scholars Research Library; Der Pharm. Lett  3:350-356.

Indexed at, Google Scholar, Crossref

4. Lahare Y, Phuge AN, Gite AL, Jadhav AK (2014) A Review on Ultraviolet Spectrophotometric Determination of Rosuvastatin Calcium In Marketed Formulation. Int J Pure App Biosci 2:169-174.

Google Scholar

5. Ramu K, Aleti P, Venisetty Rk (2013) Analytical Method Development and Validation of Simultaneous Estimation Of Ezetamibe And Rosuvastatin In Tablet Dosage Form By Rp-Hplc. Int J Pharm Biol Page No.343-353.

Google Scholar

6. Brunet R, Boer D,Guillén-Gosálbez G, Jiménez L (2015)Reducing the cost, environmental impact and energy consumption of biofuel processes through heat integration. ChemEng Res Des 93:203-212.

Indexed at, Google Scholar, Crossref

7. Kautto J, Realff MJ, Ragauskas AJ, Kässi T (2014)Economic Analysis of an Organosolv Process for Bioethanol Production. Bio Resources 9:6041-6072.

Indexed at, Google Scholar

8. Nguyen TTH, Kikuchi Y, Noda M, Hirao M (2015)A New Approach for the Design and Assessment of Bio-based Chemical Processes toward Sustainability. Ind Eng Chem Res 54: 5494-5504.

Indexed at, Google Scholar, Crossref

9. Rajendran K, Rajoli S, Teichert O, Taherzadeh MJ (2014) Impacts of retrofitting analysis on first  generation ethanol production: process design and techno-economics. Bioprocess BiosystEng 38:389-397  

Indexed at, Google Scholar, Crossref

10. Rossetti I, Lasso J, Compagnoni M, Guido G De (2015) H2 Production from Bioethanol and its Use in Fuel-Cells. ChemEng Trans 43:229-234.

Indexed at, Google Scholar, Crossref