Green Synthesis of Metal Nanoparticles for Antimicrobial Activity

Abstract

The development and extensive spread of multi-drug resistant bacteria are considered as a major public health concern. Failures to control severe infections due to antibiotic resistance have augmented healthcare costs as well as patient morbidity and mortality. Presently, natural product-based therapeutics are gaining significant attention both for their antimicrobial effectiveness and for not persuading drug resistance. Furthermore, recent developments in nanoscience on new drug delivery systems built on nanostructured materials from plants and microbes have emerged which focus on targeted delivery and controlled release of therapeutic agents. This review examines the recent investigations on the biological activities of plant and bacterial biological material for silver nanoparticle (AgNP) synthesis. Also, the underlying mechanism of antimicrobial activities of silver nanoparticles against human pathogens will be discussed. A fact of the biological activities and/or chemical responses of plants is required, not only for the discovery of new therapeutic agents, but because such evidence may be of value in disclosing new sources of already known biologically active compounds.

Biomimetic Metallic Nanostructures for Biomedical Applications, Catalysis, and Beyond

“…The use of natural or biomolecular templates, on the other hand, eliminates the need for toxic chemicals in the synthesis, leading to the formation of biometal NPs with good biocompatibility and unique biofunctionalities (e.g., antiviral) as highlighted below. 31,34,38,39 2.1.1. DNA-Templated Synthesis.…”

“…130 Therefore, a great deal of research has been conducted on how plants can be used as promising green biofactories to produce metal NPs. 34 Similar to the bacterial system, plants have diverse cell surveillance mechanisms that effectively detoxify the overconcentration of metallic cations. 156 Furthermore, it has been demonstrated that the as- synthesized metal NPs accumulate in some organelles of plant cells, such as vacuoles.…”

“…156 Furthermore, it has been demonstrated that the as- synthesized metal NPs accumulate in some organelles of plant cells, such as vacuoles. 32,34 Plants produce a large array of metabolites compared to other living organisms. 157 They produce several primary and secondary metabolites, including amino acids, sugars, lipids, proteins carbohydrates, vitamins, water-soluble polyphenols (e.g., flavonoids, phenolic acids, tannins, anthocyanins, stilbenes, and lignans), alkaloids, quinines, terpenoids, and saponins.…”

“…For the bioreduction process, metal ions are reduced through biological agents, resulting in the formation of biometal NPs with high stability, which can be easily separated from the reaction media. While the biosorption mechanism requires the metallic ions to be adsorbed onto the microorganism biomass and transformed into biometal NPs through an ion-exchange, nucleation, precipitation, and complexation process. , In the following sessions, we will review the use of different types of biomolecular templates and biological systems (e.g., microorganism and plants) for the synthesis of biometal NPs as illustrated in Figure a.…”

“…In the traditional colloidal synthesis, surfactants (e.g., PVP) are used as capping agents to control the size and morphology of metal NPs, which are difficult to remove from the products and constitute environmental pollution. The use of natural or biomolecular templates, on the other hand, eliminates the need for toxic chemicals in the synthesis, leading to the formation of biometal NPs with good biocompatibility and unique biofunctionalities (e.g., antiviral) as highlighted below. ,,, …”