Shibani Basu

Biosynthesis, characterisation and antimicrobial activity of silver and gold nanoparticles byDolichos biflorusLinn seed extract

ABSTRACT The bioreduction method employed for the synthesis of colloidal AgNPs and AuNPs is reported here. Methanolic and aqueous extracts of Dolichos biflorus Linn seed was used as the bio-reducing agent. The structural and morphological aspects of the synthesised metal nanoparticles were investigated using X-ray diffraction (XRD), energy-dispersive spectroscopy (EDX), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD, revealed crystalline nature of the synthesised particles, UV–vis spectrophotometric analysis showed characteristic absorption peak for both AgNPs and AuNPs. EDX analysis confirmed the presence of elemental silver and gold particles and the average size and morphology were determined by SEM and TEM. The synthesised AgNPs exhibited good antibacterial potential whereas AuNPs showed poor activity against human pathogenic, gram-positive bacteria such as Staphylococcus aureus, Bacillus subtilis and gram-negative bacteria, such as Escherichia coli, Pseudomonas aeruginosa.

Βeta-Lactams as Clinically Active Medicines

The clinical use of diverse β-lactams as antibiotics is continued to grow as the main weapon against bacterial diseases. Since the discovery of penicillins, other β-lactam antibiotics are discovered and they save millions of life. Importantly, β-lactams are also used as medicines for different types of medical disorders. Some of them are found to be anticancer agents, anticholesterol agents. Because of the tremendous medicinal properties, many studies are directed to identify their mechanism of action against these diseases. Despite the significant importance of clinically active β-lactams no description covering their use and resistance in recent years is performed. Therefore, we report here the medical use of β-lactams as therapeutic agents with the understanding that researchers may find this chapter useful in their endeavor in future research.

Green synthesis and swelling behavior of Ag-nanocomposite semi-IPN hydrogels and their drug delivery using Dolichos biflorus Linn

ABSTRACT Acrylic-based hydrogels with great potentials for usage in medical area were principally synthesized as per two strategies. The first involved reaction containing silver nitrate to yield silver nanoparticles (AgNPs) where Dolichos biflorus Linn acted as both reducing agent and stabilizing for green synthesized AgNPs was added to the reaction medium to establish reduction of Ag+ to AgNPs. The second strategy entailed preparation of nanosilver composite hydrogel that is carried out by free radical polymerization reaction in presence of Sodium Alginate and acrylamide (AAm) under the same conditions. In both strategies, factors affecting the characterization of AgNPs-loaded hydrogels were studied. Analysis and characterization of the so obtained hydrogels were performed through monitoring swelling behavior, FTIR spectroscopy, SEM, EDX, UV–Vis spectrophotometer, XRD, and TEM. Results indicate that modifying AAm and silver ion can improve swelling properties of the resultant nanocomposite hydrogel. pH response of this nanocomposite hydrogel in different pH made it suitable for drug delivery applications.

Antioxidant Edible Mushrooms: A Green and Rapid Electrochemical Study with the Aqueous Extracts

A greener and rapid electrochemical technique was performed by indium doped tin oxide (ITO) glasses as working electrode in cyclic and differential pulse voltammetry to screen the antioxidant activities of the aqueous extracts of different species of edible mushrooms Plureotus florida, Calocybe indica and Tricholoma gigantum found in West Bengal. The ITO glasses as electrode was very sensitive for the detection of electrical potentiality with 10 μl of 20 μg/ml (volume and concentration) concentration in phosphate buffer (pH 7.0) for the isolated aqueous extracts of mushrooms along with ascorbic acid and gallic acid as standards. In addition to the electrochemical study, the spectrophotometric assays were used to evaluate the antioxidant constituents, their reducing power and free radical scavenging ability of the extracts. The results obtained from both electrochemical and spectrophotometrical assays were in good agreement to each other for the detectable and significant range of antioxidant potentiality of these extracts. The present electrochemical ITO electrode method is a greener, efficient, cost effective, recyclable, and less cumbersome for detection of antioxidant properties of mushrooms compared to the other available electrochemical techniques.

Polysaccharides from Dolichos biflorus Linn and Trachyspermum ammi Linn seeds: isolation, characterization and remarkable antimicrobial activity

Polysaccharides are structurally complex and essential constituents of life, and therefore, studies directed to these kinds of molecules have received scientific attention. Despite an easy availability of Dolichos biflorus Linn and Trachyspermum ammi (Linn) seeds isolation, characterization and antimicrobial studies of polysaccharides derived from these two natural sources have not been investigated. Therefore, we report here isolation of polysaccharides, their purification and characterization from Dolichos biflorus Linn and Trachyspermum ammi (Linn) seeds. Gel permeation chromatography, GC–MS, SEM, XRD, EDX and FT-IR analyses show the presence of three pentose sugar such as d-ribose, d-arabinose, d-xylose and hexose sugar such as d-mannose, d-galactose and d-glucose. Unprecedented antimicrobial activity of these polysaccharides against Gram positive bacteria such as Staphylococcus aureus and Bacillus subtilis and Gram negative bacteria such as Escherichia coli and Pseudomonas aeruginosa are established.

Metallic Materials From E-Waste

With the wake of the ever advancing electronics, lies an impending danger of waning heaps of electronic waste. The threat is multifaceted, hazardous yet valuable. E-waste extensively constitutes of precious and semi-precious metals, thus lucrative. Moreover, toxicity has forced trans-boundary movements of e-waste across globe as an enterprise. E-waste scenarios of the world and its significant contributors are outlined. Additionally, challenges faced in implementing metal recovery from e-waste are addressed. Collection and efficient technology play crucial roles. The e-consumers bears a responsibility to act in consonance with the authorities, enhance e-waste collection for further treatment for a better sustainable future.