The ability of organisms and organic compounds to reduce metal ions and stabilize them into nanoparticles (NPs) forms the basis of green synthesis. To date, synthesis of NPs from various metal ions using a diverse array of plant extracts has been reported. However, a clear understanding of the mechanism of green synthesis of NPs is lacking. Although most studies have neglected to analyze the green-synthesized NPs (GNPs) for the presence of compounds derived from the extract, several studies have demonstrated the conjugation of sugars, secondary metabolites, and proteins in these biogenic NPs. Despite several reports on the bioactivities (antimicrobial, antioxidant, cytotoxic, catalytic, etc.) of GNPs, only a handful of studies have compared these activities with their chemically synthesized counterparts. These comparisons have demonstrated that GNPs possess better bioactivities than NPs synthesized by other methods, which might be attributed to the presence of plant-derived compounds in these NPs. The ability of NPs to bind with organic compounds to form a stable complex has huge potential in the harvesting of precious molecules and for drug discovery, if harnessed meticulously. A thorough understanding of the mechanisms of green synthesis and high-throughput screening of stabilizing/capping agents on the physico-chemical properties of GNPs is warranted to realize the full potential of green nanotechnology.

/pdf/secondary-metabolites-in-the-green-synthesis-of-metallic-1297vspyz3.pdf

Secondary Metabolites in the Green Synthesis of Metallic Nanoparticles

Nanotechnology is an exciting and powerful discipline of science; the altered properties of which have offered many new and profitable products and applications. Agriculture, food and medicine sector industries have been investing more in nanotechnology research. Plants or their extracts provide a biological synthesis route of several metallic nanoparticles which is more eco-friendly and allows a controlled synthesis with well-defined size and shape. The rapid drug delivery in the presence of a carrier is a recent development to treat patients with nanoparticles of certain metals. The engineered nanoparticles are more useful in increasing the crop production, although this issue is still in infancy. This is simply due to the unprecedented and unforeseen health hazard and environmental concern. The well-known metal ions such as zinc, iron and copper are essential constituents of several enzymes found in the human system even though the indiscriminate use of similar other metal nanoparticle in food and medicine without clinical trial is not advisable. This review is intended to describe the novel phytosynthesis of metal and metal oxide nanoparticles with regard to their shape, size, structure and diverse application in almost all fields of medicine, agriculture and technology. We have also emphasized the concept and controversial mechanism of green synthesis of nanoparticles.

/pdf/phytosynthesis-of-nanoparticles-concept-controversy-and-1ss82h4w7z.pdf

Phytosynthesis of nanoparticles: concept, controversy and application.

Gold nanoparticles (AuNPs) are extensively studied nanoparticles (NPs) and are known to have profound applications in medicine. There are various methods to synthesize AuNPs which are generally categorized into two main types: chemical and physical synthesis. Continuous efforts have been devoted to search for other more environmental-friendly and economical large-scale methods, such as environmentally friendly biological methods known as green synthesis. Green synthesis is especially important to minimize the harmful chemical and toxic by-products during the conventional synthesis of AuNPs. Green materials such as plants, fungi, microorganisms, enzymes and biopolymers are currently used to synthesize various NPs. Biosynthesized AuNPs are generally safer for use in biomedical applications since they come from natural materials themselves. Multiple surface functionalities of AuNPs allow them to be more robust and flexible when combined with different biological assemblies or modifications for enhanced applications. This review focuses on recent developments of green synthesized AuNPs and discusses their numerous biomedical applications. Sources of green materials with successful examples and other key parameters that determine the functionalities of AuNPs are also discussed in this review.

/pdf/recent-developments-in-the-facile-bio-synthesis-of-gold-4c04pa6yv4.pdf

Recent Developments in the Facile Bio-Synthesis of Gold Nanoparticles (AuNPs) and Their Biomedical Applications.

Metal nanoparticles are being extensively used in biomedical fields due to their small size-to-volume ratio and extensive thermal stability. Gold nanoparticles (AuNPs) are an obvious choice for biomedical applications due to their amenability of synthesis, stabilization, and functionalization, low toxicity, and ease of detection. In the past few decades, various chemical methods have been used for the synthesis of AuNPs, but recently, newer environment friendly green approaches for the synthesis of AuNPs have gained attention. AuNPs can be conjugated with a number of functionalizing moieties including ligands, therapeutic agents, DNA, amino acids, proteins, peptides, and oligonucleotides. Recently, studies have shown that gold nanoparticles not only infiltrate the blood vessels to reach the site of tumor but also enter inside the organelles, suggesting that they can be employed as effective drug carriers. Moreover, after reaching their target site, gold nanoparticles can release their payload upon an external or internal stimulus. This review focuses on recent advances in various methods of synthesis of AuNPs. In addition, strategies of functionalization and mechanisms of application of AuNPs in drug and bio-macromolecule delivery and release of payloads at target site are comprehensively discussed.

/pdf/a-review-on-the-synthesis-and-functionalization-of-gold-2sv4w1db63.pdf

A Review on the Synthesis and Functionalization of Gold Nanoparticles as a Drug Delivery Vehicle.

Nanotechnology is the formation, running and use of operation at the nanomaterial size scale (1-100 nm). Nanoscale materials can also be obtained by biological synthesis materials via eco-friendly green chemistry based technique. Current development and numerous strategies involved in the green synthesis of nanoparticles were focussed. This review mainly focused on plants which include scientific name, family name, common name, plant parts, its characterization, size and shape of the nanoparticles. Plant extract which was done experimentally gives its various characterization which leads to the identification of compounds of different nano size and shape. Biosynthesis of gold nanoparticles is in different shapes like spherical, rod, cubic, triangle and also in different sizes. Various application and importance of gold nanoparticles in numerous fields were discussed. The mark of the review is to provide an overview of recent learning in biosynthesized nanoparticles, its characterization and their potential applications.

Phyto-assisted synthesis, characterization and applications of gold nanoparticles – A review

https://cyberleninka.org/article/n/336269.pdf

An eco-friendly method of synthesizing gold nanoparticles using an otherwise worthless weed pistia (Pistia stratiotes L.).

Biomimetic synthesis of silver nanoparticles using the amphibious weed ipomoea and their application in pollution control

Gainful utilization of the highly intransigent weed ipomoea in the synthesis of gold nanoparticles

The history of plant-based nanoparticle synthesis is traced briefly. All the work done in this field till the present date is then summarized. The extent of the understanding of the role of pH, temperature, reducing/capping agents, metal–plant stoichiometry, stirring, light, etc., in controlling the shapes and sizes of nanoparticles is discussed.

Biomimetic Synthesis of Nanoparticles Using Aqueous Extracts of Plants (Botanical Species)

The functional aspect of nanotechnology (NBT) is driven either to accelerate the performance of materials and/or to reduce the quantity of materials that are used for the purpose. Most significantly, its potential attribute to the environment includes the treatment and remediation, sensing and detection, and pollution prevention. In general nano-bio remediation (NBR) involves the use of nano-materials either in in-situ (in place), or ex-situ (off-place) treatment of contaminated materials. To accomplish this, the elemental or zero-valent metals and like materials in nano-form (1-100 nm) have been applied as an instinctive need to embrace sustainable environment. The use of nanomaterials initially reduces the biodegradable contaminants and then it promotes to achieve the standard levels. Thus, the role of nano-materials could be an efficient, effective approach to remediate the environmental contaminant sustainably. However, further research is required to record the detailed fate of the nano-materials that are used in environment remediation. Nano-Bioremediation: Nanotechnology and Bioremediation

J. Anuradha

Papers

An eco-friendly method of synthesizing gold nanoparticles using an otherwise worthless weed pistia (Pistia stratiotes L.).

Biomimetic synthesis of silver nanoparticles using the amphibious weed ipomoea and their application in pollution control

Gainful utilization of the highly intransigent weed ipomoea in the synthesis of gold nanoparticles

Biomimetic Synthesis of Nanoparticles Using Aqueous Extracts of Plants (Botanical Species)

Nano-Bioremediation: Nanotechnology and Bioremediation