Silver Nanoparticles

Synthesis, Functionalization and Applications

Parteek Prasher, Mousmee Sharma

• Verlag: Bentham Science Publishers
• Jahr: 2022
• ISBN:
  9789815050530
• Thema: Technology & Engineering
• Thema: Nanotechnology & MEMS

Silver Nanoparticles: Synthesis, Functionalization and Applications [Provided by Editors] The book "SILVER NANOPARTICLES: Synthesis, functionalization and Applications" presents a detailed investigation of the various methods of synthesizing AgNPs via chemical and green methods. The surface engineered silver nanoparticles present immense applications in the contemporary era starting from theranostics, biosensors, next generation antimicrobials, fabrication of solar cells, to the effective soil management leading to a sustainable agriculture. The widespread utility of AgNPs necessitates a comprehensive understanding of the operational strategies revolving around their surface modification and conjugation. This book epigrammatically discusses the candidature of engineered AgNPs as the material of future [Edited by Taimur] Silver Nanoparticles: Synthesis, Functionalization and Applications presents detailed information about the range of methods of synthesizing silver nanoparticles (AgNPs). The book systematically delves into the subject with an introductory chapter before moving to chemical synthesis of AGnPs and fabrication methods which help in assigning functional properties for useful nanomaterials. Basic and advanced synthetic methods like surface functionalization and bioconjugation are covered. Additionally, the book informs about impactful applications of AGNPs across a range of industries. Through this book, readers will be able to understand the importance of silver nanoparticles as a futuristic material in scientific investigations and gain a comprehensive understanding of the operational strategies revolving around their surface modification and conjugation. Key Features: -Covers the basics of silver nanoparticle (AGNP) synthesis -Focuses on green methods of AGNPs - Covers information about surface modification and functionalization of AGNPs with different molecules (including biomolecules) -Covers a range of applications of AGNPs -Includes advanced applications of AGNPs in next-generation antibiotics Silver Nanoparticles: Synthesis, Functionalization and Applications a handy reference for scholars in advanced chemical engineering, materials science and pharmacology programs as well as anyone who wants to know all about silver nanoparticles.

Synthesis of Silver Nanoparticles

Parteek Prasher, Mousmee Sharma

Abstract

The synthesis of AgNPs occurs by traditional chemical synthesis, which requires reducing agents to convert the ionic silver to metallic form and a capping agent that stabilizes the colloidal suspension of AgNPs. While the green synthesis inculcates the use of natural agents and their extract or dry biomass that play a dual role of reducing and capping agents. Mainly, the alkaloids, natural products, terpenes, polysaccharides, and coumarins present in the biomass or their extract serve as the reducing/ capping agent for the synthesis of AgNPs via the green route. The present chapter discusses the modes of synthesis of AgNPs by the green routes.

Keywords: AgNPs morphology, Capping agent, Chemical synthesis, Green synthesis, Microbial synthesis.

1. Chemical Synthesis

The chemical synthesis of AgNPs starts with the reduction of Ag(I) solution in the presence of a suitable reducing agent to obtain Ag(0) nuclei aggregates in the colloidal solution. The metallic silver nuclei in the presence of a suitable stabilizing agent coalease to form clusters in the colloidal solution that generate colloidal stabilized AgNPs. Further modifications on AgNPs for fine-tuning of their surface and morphology occur in the presence of chemical and physical modifications in the colloidal state. Fig. (1) illustrates the formation of surface functionalized AgNPs. Mainly the chemical reducing agents such as NaBH₄ and LiAlH₄ represent the most commonly used reagents for the conversion of silver ions in solution phase to metallic silver. The stabilizing agents used in chemical synthesis mainly include a synthetic polymer that prevents the coalease of AgNPs in colloidal phase and keeps them dispersed in the solution itself. However, in the present era, more emphasis occurs on the green methods of AgNPs synthesis owing to environmental sustainability and low harm to the ecosystem.

1.1. Green Synthesis

Fig. (2) highlights the various sources for the green synthesis of AgNPs. Mainly, the various phytochemicals, natural products, macromolecules, tannins, lignins,

coumarins, terpenes, and heterocyclic or spirocyclic components present in the sources mentioned in Fig. (2) assist in the AgNPs synthesis. These agents serve the dual role of being a reducing and coupling agent and provide a high yield of AgNPs. Tables 1-3 depict the green synthesis of AgNPs by natural sources in the form of microbes and agrowaste.

Fig. (1))
Sequence of steps for the synthesis of surface functionalized AgNPs.

Fig. (2))
Sources for the green synthesis of AgNPs.

Table 1 Synthesis by bacteria.

Bacteria	AgNPs Characteristics	Reducing Agent	Refs.
Extracellular synthesis by Pseudomonas antarctica, Pseudomonas proteolytica, Pseudomonas meridiana, Arthrobacter kerguelensis and Arthrobacter gangotriensis and two mesophilic bacteria Bacillus indicus and Bacillus cecembensis	Spherical shape, average diameter in the range 6-13 nm	Cell free culture supernatant	[1]
Endophytic bacterium was isolated from the plant red fountain grass (Pennisetum setaceum)	Monodispersed spherical shape, average diameter in the range 83-176 nm	Bacterial wet biomass	[2]
Acidophilic actinobacterial SH11 strain isolated from pine forest soil	Polydispersed spherical shape, mean diameter 13.2 nm	Cell free culture supernatant	[3]
Endophytic Bacterium Pantoea ananatis	Spherical shape, average diameter in the range 8.06-91.32 nm	Cell free culture supernatant	[4]
Bacillus brevis (NCIM 2533)	Spherical shape, average diameter in the range 41-68 nm	Bacterial cell filtrate	[5]
Extracellular biosynthesis with Bacillus methylotrophicus DC3 strain	Spherical shape, average diameter in the range 10-30 nm	Bacterial dry biomass	[6]
Extracellular synthesis by Soil bacteria Cupriavidus sp	Spherical, crystalline shape, average diameter in the range 10-50 nm	Cell free supernatant	[7]
Bacterial exopolysacch...