Synthesis of metallic nanoparticles using plant extracts.

Multidrug resistance of the pathogenic microorganisms to the antimicrobial drugs has become a major impediment toward successful diagnosis and management of infectious diseases. Recent advancements in nanotechnology-based medicines have opened new horizons for combating multidrug resistance in microorganisms. In particular, the use of silver nanoparticles (AgNPs) as a potent antibacterial agent has received much attention. The most critical physico-chemical parameters that affect the antimicrobial potential of AgNPs include size, shape, surface charge, concentration and colloidal state. AgNPs exhibits their antimicrobial potential through multifaceted mechanisms. AgNPs adhesion to microbial cells, penetration inside the cells, ROS and free radical generation, and modulation of microbial signal transduction pathways have been recognized as the most prominent modes of antimicrobial action. On the other side, AgNPs exposure to human cells induces cytotoxicity, genotoxicity and inflammatory response in human cells in a cell-type dependent manner. This has raised concerns regarding use of AgNPs in therapeutics and drug delivery. We have summarized the emerging endeavors that address current challenges in relation to safe use of AgNPs in therapeutics and drug delivery platforms. Based on research done so far, we believe that AgNPs can be engineered so as to increase their efficacy, stability, specificity, biosafety and biocompatibility. In this regard, three perspectives research directions have been suggested that include 1) synthesizing AgNPs with controlled physico-chemical properties, 2) examining microbial development of resistance towards AgNPs, and 3) ascertaining the susceptibility of cytoxicity, genotoxicity, and inflammatory response to human cells upon AgNPs exposure.

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Mechanistic Basis of Antimicrobial Actions of Silver Nanoparticles.

Recent biomedical applications of gold nanoparticles: A review.

Infectious diseases remain one of the leading causes of morbidity and mortality worldwide. The WHO and CDC have expressed serious concern regarding the continued increase in the development of multidrug resistance among bacteria. Therefore, the antibiotic resistance crisis is one of the most pressing issues in global public health. Associated with the rise in antibiotic resistance is the lack of new antimicrobials. This has triggered initiatives worldwide to develop novel and more effective antimicrobial compounds as well as to develop novel delivery and targeting strategies. Bacteria have developed many ways by which they become resistant to antimicrobials. Among those are enzyme inactivation, decreased cell permeability, target protection, target overproduction, altered target site/enzyme, increased efflux due to over-expression of efflux pumps, among others. Other more complex phenotypes, such as biofilm formation and quorum sensing do not appear as a result of the exposure of bacteria to antibiotics although, it is known that biofilm formation can be induced by antibiotics. These phenotypes are related to tolerance to antibiotics in bacteria. Different strategies, such as the use of nanostructured materials, are being developed to overcome these and other types of resistance. Nanostructured materials can be used to convey antimicrobials, to assist in the delivery of novel drugs or ultimately, possess antimicrobial activity by themselves. Additionally, nanoparticles (e.g., metallic, organic, carbon nanotubes, etc.) may circumvent drug resistance mechanisms in bacteria and, associated with their antimicrobial potential, inhibit biofilm formation or other important processes. Other strategies, including the combined use of plant-based antimicrobials and nanoparticles to overcome toxicity issues, are also being investigated. Coupling nanoparticles and natural-based antimicrobials (or other repurposed compounds) to inhibit the activity of bacterial efflux pumps; formation of biofilms; interference of quorum sensing; and possibly plasmid curing, are just some of the strategies to combat multidrug resistant bacteria. However, the use of nanoparticles still presents a challenge to therapy and much more research is needed in order to overcome this. In this review, we will summarize the current research on nanoparticles and other nanomaterials and how these are or can be applied in the future to fight multidrug resistant bacteria.

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Nano-Strategies to Fight Multidrug Resistant Bacteria-"A Battle of the Titans".

Biogenic synthesis of nanoparticles: A review

Facile green synthesis of gold nanoparticles using leaf extract of antidiabetic potent Cassia auriculata.

Blue green alga mediated synthesis of gold nanoparticles and its antibacterial efficacy against Gram positive organisms.

Facile synthesis of silver chloride nanoparticles using marine alga and its antibacterial efficacy

Sargassum myriocystum mediated biosynthesis of gold nanoparticles

Silver is a potent antimicrobial agent which is used in the form of nanomaterial or as metal salts for antimicrobial applications. Antimicrobial agents have a major role in water treatment, chemical industries, food preservation, aquaculture ponds, agricultural productivity and biomedical applications. Presently, due to emergence of nanoscience and technology metallic silver nanoparticles (AgNPs) are used as antimicrobial agent and is synthesized by following various protocols. In this review article, plants and algae mediated AgNPs synthesis is highlighted and their application as an antimicrobial agent is discussed. This review will emphasize the role of biosynthesized AgNPs for its antimicrobial application which will provide further insight towards better health, environment and prevention from infectious diseases.

T. Stalin Dhas

Papers

Facile green synthesis of gold nanoparticles using leaf extract of antidiabetic potent Cassia auriculata.

Blue green alga mediated synthesis of gold nanoparticles and its antibacterial efficacy against Gram positive organisms.

Facile synthesis of silver chloride nanoparticles using marine alga and its antibacterial efficacy

Sargassum myriocystum mediated biosynthesis of gold nanoparticles

Antibacterial activity of silver nanoparticles (biosynthesis): A short review on recent advances