S. Muthukrishnan

Bio: S. Muthukrishnan is an academic researcher from Bharathidasan University. The author has contributed to research in topics: Silver nanoparticle & Micropropagation. The author has an hindex of 7, co-authored 15 publications receiving 531 citations.

Biogenic synthesis of silver nanoparticles and their antioxidant and antibacterial activity

Abstract: Nanomedicine utilizes biocompatible nanomaterials for diagnostic and therapeutic purposes. The present study reports the use of Helicteres isora root extract for the synthesis of silver nanoparticles (AgNPs). The synthesized AgNPs were initially noticed through visual color change from yellow to reddish brown and further confirmed by surface plasmonic resonance (SPR) band at 450 nm using UV–visible spectroscopy. Morphology and size of AgNPs were determined by transmission electron microscopy (TEM) analysis. X-ray diffraction (XRD) study revealed crystalline nature of AgNPs. The prolonged stability of AgNPs was due to capping of oxidized polyphenols and carboxyl protein which was established by Fourier transform infrared spectroscopy (FTIR) study. In addition, the synthesized AgNPs were tested for antioxidant and antibacterial activities. It showed good antioxidant activity as compared to butylated hydroxytoluene (BHT) and ascorbic acid as standard antioxidant. It could be concluded that H. isora root extract can be used efficiently in the production of potential antioxidant and antibacterial AgNPs for commercial application.

Catalytic Degradation of Organic Dyes using Synthesized Silver Nanoparticles: A Green Approach

Abstract: The scientific community is search in for new methods for the synthesis of metallic nanoparticles. Green synthesis has now become a vast developing area of new research groups. Here we report a green method to the synthesis of silver nanoparticles (AgNPs) using the different parts of Vishanika or Indian screw tree, an ayurvedic medicinal tree. This is nontoxic, eco-friendly and low cost method. The reduction and stabilization capability of the plant extracts of different parts are described. The size and structure of the silver can be characterized by varying the plant parts of the vishanika. The biosynthesized nanoparticles are characterized by using UV–VIS spectroscopy, TEM, XRD, DLS and FTIR. The size and extract dependent catalytic activity of the biosynthesized nanoparticles is established in the degradation of organic dyes.

Antimicrobial, antioxidant and anticancer activity of biogenic silver nanoparticles – an experimental report

Abstract: In the present study, use of a Helicteres isora stem bark extract for the biosynthesis of AgNPs is described. It was observed that the aqueous silver (Ag+) ions, once associated in the stem bark extract, were reduced in solution, thereby leading to formation of the stable AgNPs. These AgNPs were characterized using several techniques. The nanoparticles show a maximum absorbance at 419–431 nm in the ultraviolet-visible spectra. The presence of the steroid sapogenin was identified using Fourier transform-infrared (FTIR) spectroscopy. The reduction of the Ag+ ions to elemental silver was investigated by using X-ray diffraction (XRD). Transmission electron microscopy (TEM) revealed the formation of monodisperse, with low polydispersity, nanoparticles of 25.55 nm, and the presence of elemental silver was confirmed through energy dispersive spectroscopy (EDX) analysis. The AgNPs showed antioxidant activities such as DPPH, hydrogen peroxide and nitric oxide radical scavenging and a reducing power compared to the standard compounds. The antibacterial effect was determined against test strains, showing significant inhibition. The antiproliferative activity of the AgNPs was demonstrated using oral carcinoma (KB) cells with MTT, and confirmed using AO/EtBr, comet assay, DCFH-DA and Rhodamine 123 staining. In the toxicity study, a significant mortality rate was observed against Artemia with an IC50 concentration of 70 μg mL−1 and 108 h exposure. The NPs showed as cytotoxic against Artemia at 108 h, so they are cytotoxic at high concentrations and after prolonged exposure.

Anticancer activity of biogenic nanosilver and its toxicity assessment on Artemia salina- evaluation of mortality, accumulation and elimination: An experimental report

Abstract: The study was focused on assessment of anticancer activity and investigate the toxicity against Artemia salina adult and nauplii of biogenic silver nanoparticles (AgNPs) synthesized from in vitro derived Ceropegia thwaitesii leaf. These AgNPs were characterized using transmission electron micrograph (TEM) and Atomic force microscopy (AFM). TEM revealed the formation of mono dispersed with low polydispersity nanoparticles with size of 41.34 nm, and the presence of elemental silver was correlated with EDX. AFM topographical image conform the spherical nature of the AgNPs. These AgNPs exhibited a dose-dependent cytotoxicity against oral carcinoma (KB) cells and it was confirmed by MTT, Ao/EtBr, COMET assay and Rhodamine 123 staining. For toxicity study did not induce significant mortality against Artemia (adult and nauplii) at IC 50 concentration 97.03 μg/ml at exposure time. The accumulation and elimination rate of nauplii was 7.5 and 0.85 μg/g and 14.5 and 1.06 μg/g at 24 and 108 h respectively, exposure at 200 μg/ml concentration. Whereas accumulation and elimination rate of adult was 9 and 17 μg/g and 1.15 and 1.86 μg/g at 24 and 108 h respectively, exposure at 200 μg/ml concentration. From these results A. salina test may expedite toxicity experiments and decrease the costs.

A review on biosynthesis of silver nanoparticles and their biocidal properties.

Abstract: Use of silver and silver salts is as old as human civilization but the fabrication of silver nanoparticles (Ag NPs) has only recently been recognized. They have been specifically used in agriculture and medicine as antibacterial, antifungal and antioxidants. It has been demonstrated that Ag NPs arrest the growth and multiplication of many bacteria such as Bacillus cereus, Staphylococcus aureus, Citrobacter koseri, Salmonella typhii, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Vibrio parahaemolyticus and fungus Candida albicans by binding Ag/Ag+ with the biomolecules present in the microbial cells. It has been suggested that Ag NPs produce reactive oxygen species and free radicals which cause apoptosis leading to cell death preventing their replication. Since Ag NPs are smaller than the microorganisms, they diffuse into cell and rupture the cell wall which has been shown from SEM and TEM images of the suspension containing nanoparticles and pathogens. It has also been shown that smaller nanoparticles are more toxic than the bigger ones. Ag NPs are also used in packaging to prevent damage of food products by pathogens. The toxicity of Ag NPs is dependent on the size, concentration, pH of the medium and exposure time to pathogens.

A review on green synthesis of silver nanoparticles and their applications

Abstract: Development of reliable and eco-accommodating methods for the synthesis of nanoparticles is a vital step in the field of nanotechnology. Silver nanoparticles are important because of their exceptional chemical, physical, and biological properties, and hence applications. In the last decade, numerous efforts were made to develop green methods of synthesis to avoid the hazardous byproducts. This review describes the methods of green synthesis for Ag-NPs and their numerous applications. It also describes the comparison of efficient synthesis methods via green routes over physical and chemical methods, which provide strong evidence for the selection of suitable method for the synthesis of Ag-NPs.

Antibacterial properties and toxicity from metallic nanomaterials.

Abstract: The era of antibiotic resistance is a cause of increasing concern as bacteria continue to develop adaptive countermeasures against current antibiotics at an alarming rate In recent years, studies have reported nanoparticles as a promising alternative to antibacterial reagents because of their exhibited antibacterial activity in several biomedical applications, including drug and gene delivery, tissue engineering, and imaging Moreover, nanomaterial research has led to reports of a possible relationship between the morphological characteristics of a nanomaterial and the magnitude of its delivered toxicity However, conventional synthesis of nanoparticles requires harsh chemicals and costly energy consumption Additionally, the exact relationship between toxicity and morphology of nanomaterials has not been well established Here, we review the recent advancements in synthesis techniques for silver, gold, copper, titanium, zinc oxide, and magnesium oxide nanomaterials and composites, with a focus on the toxicity exhibited by nanomaterials of multidimensions This article highlights the benefits of selecting each material or metal-based composite for certain applications while also addressing possible setbacks and the toxic effects of the nanomaterials on the environment

Bio-inspired synthesis of metal nanomaterials and applications

Abstract: This critical review focuses on recent advances in the bio-inspired synthesis of metal nanomaterials (MNMs) using microorganisms, viruses, plants, proteins and DNA molecules as well as their applications in various fields. Prospects in the design of bio-inspired MNMs for novel applications are also discussed.