Pranesh Chowdhury

Synthesis of polypyrrole nanoparticles and its grafting with silica gel for selective binding of chromium(VI)

Polypyrrole nanoparticles of desired structure have been synthesized through simple micelle technique. It is then grafted with functionalized silica gel to develop a novel organic-inorganic hybrid material. The role of dimethyl dichloro silane (coupling agent) in grafting is demonstrated. The nanoparticles are characterized by TEM, SEM and TGA. Grafting reactions are evaluated by spectral (FTIR) analysis and chemical test. The Cr(VI) binding behavior of the composite is studied in various pH of the medium. The selectivity in binding Cr(VI) is monitored. The metal ion adsorption capacity and surface area of the material are found to be 38 mg/g and 235 m(2)/g, respectively.

Evidence of reactive oxygen species (ROS) mediated apoptosis in Setaria cervi induced by green silver nanoparticles from Acacia auriculiformis at a very low dose.

Green synthesis of silver nanomaterial plays a pivotal role in the growing field of nanotechnology. Development of anti-parasitic drugs from plant metabolites has been in regular practice from the ancient period but most of them were discarded due to their inefficiency to control diseases effectively. At present, nanoparticles are used for developing anti-parasitic therapy for their unique properties such as smallest in size, bio-ability, bio-compatibility and penetration capacity into a cell. The present study aims at synthesis of silver nanoparticles (AgNPs) by using funicles extract of Acacia auriculiformis and tests its efficacy as antifilarial. Experimental evidence show that AgNPs are effective at a very low concentration compared to crude plant extracts. Synthesis of these nanoparticles is a single-step, biogenic, cost effective and eco-friendly process. Synthesized nanoparticles were characterized by UV-Vis spectroscopy, TEM, SAED, FTIR, EDX, FESEM and Z-potential. The antifilarial efficacy of AgNPs was tested against different life cycle stages of bovine filarial parasite Setaria cervi by morphological study, motility assessment and viability assay. These nanoparticles are found to have antifilarial activity with LC50 of 5.61 μg/mL and LC90 of 15.54 μg/mL against microfilaria of S. cervi. The microscopic findings and the detailed molecular studies confirmed that green synthesized AgNPs were effective enough to induce apoptosis through up regulation of ROS (reactive oxygen species).

Design and green synthesis of polymer inspired nanoparticles for the evaluation of their antimicrobial and antifilarial efficiency

Polymer inspired silver nano particles (AgNPs), endowed with high biochemical potency and very low cytotoxicity, were designed and synthesized through a tyrosine controlled green process. In contrary to other conventional techniques, the process was so optimized so that the least amount of reducing and stabilizing agents could generate the maximum possible amount of stable nanoparticles. The role of tyrosine as reducing as well as stabilizing agent was found to be dependent on the level of its concentration. Biocompatible polymers inspired the stability and biological activity of the synthesized nanoparticles to a great extent. The formation of AgNPs was monitored spectroscopically (UV-Vis) both in the presence and absence of biocompatible polymers. Biochemical effects of the polymer stabilized metal nano particles were studied in terms of antiparasitic (antifilarial), antibacterial and antifungal activities. The particles were found to be strongly interactive with the principle cellular bio-molecule (viz. DNA and protein) which might be the reason behind their bioactivity. Particularly against filarial parasites, the synthesized AgNPs were able to induce apoptosis through increasing the level of key regulator of cell death and fragmentation of genomic DNA. Among the biocompatible polymers used, chitosan improved the stability and bio-activity of the composites significantly as evident from the bioactivity and molecular studies like Circular Dichorism (CD) spectroscopic analysis as well.

Development of chitosan based gold nanomaterial as an efficient antifilarial agent: A mechanistic approach

The gold nanoparticles (AuNPs) have been synthesized biogenically by using black pepper (Piper nigrum) extract according to the principles of green chemistry in presence and absence of a biopolymer, chitosan. A comprehensive study (up to cellular level) on the antifilarial (against Setaria cervi) activity of AuNPs has been made for the first time with a view to use it clinically. The bioactivity of biopolymer capped biogenic AuNP increases significantly compared to simple biogenic AuNP. The biopolymer plays an important role in inspiring AuNP through its inherent positive charges and hydrophobicity. The developed nanomaterial boosts the production of ROS (reactive oxygen species) and misbalances the antioxidant parameters of parasites such as GSH, GST, GPx, SOD and catalase. The produced ROS ultimately induces oxidative stress, which leads to apoptotic cell death in filarial worms. The synthesized nanomaterials exhibit negligible toxicity towards human PBMCs. The present study may serve as a fruitful platform to explore biopolymer capped gold nanoparticles as efficient antifilarial therapeutics.

Carbohydrate polymer inspired silver nanoparticles for filaricidal and mosquitocidal activities: A comprehensive view.

The carbohydrate polymer inspired silver nanoparticles (AgNPs) are designed and synthesized through ultrasound assisted green process using unique combination of a biomolecule (tyrosine) and a natural polymer (starch). A comprehensive mechanistic study on the reactive oxygen species (ROS) mediated filaricidal (against Setaria cervi) and mosquitocidal (against second and fourth instar larvae of Culex quinquefasciatus) activities of AgNPs has been made for the first time for controlling filariasis by taking care of both filariid and its vector. The mechanism may help in formulating antifilarial drug based on carbohydrate polymer inspired AgNPs. The role of carbohydrate polymer in inspiring bioactivity of AgNPs has been looked into and its activities have been compared with the commercially available AgNPs. Cytotoxicity of AgNPs on macrophages of Wistar rat has been evaluated to ensure its selectivity towards filariid and larvae.

Synthesis of Graft Copolymer of Poly(acrylic acid) and Poly(vinyl alcohol) in the Presence of Methylene Bisacrylamide Crosslinker and Investigation of its Efficiency in Removing Lead Ion from Aqueous Solution

A novel graft copolymer of acrylic acid onto poly(vinyl alcohol) has been synthesized and it is crosslinked by methylene bisacrylamide for the investigation of its efficiency in removing lead ion from aqueous solution. The chemical nature of the ion exchange resin has been elucidated with the help of chemical test, FTIR, TGA and DSC. Particle size (0.20 mm), surface area (85.6 m2/g), ion exchange capacity (5.3 meq H+/g), optimum pH (4.5), time (60 min) and temperature (40°C) for Pb(II) adsorption were determined. Metal ion adsorption kinetics, isotherms and thermodynamics have been studied. A plausible mechanism for lead ion exchange has been suggested.

Polymers for the extraction of chromium-role of polymers in the removal and recovery of chromium from wastewater.

The present review discusses different possible routes of removal and recovery of chromium from industry and laboratory wastewater with special emphasis on the role of polymers in this context. Polymers can play a vital role in the easy, rapid and cost effective separation of chromium from aqueous solutions. Such studies of separation are important from the standpoint of identifying selective hosts and extractors for chromium. The use of suitable polymers in the removal and recovery of chromium from solutions is discussed.

Biocompatibility of a sonochemically synthesized poly(N-isopropyl acrylamide)/silica nanocomposite

A novel inorganic–organic core–shell nanocomposite, poly(N-isopropyl acrylamide) coated silica nanoparticles (PNIPA-g-FSNP), has been synthesized sonochemically for the first time following the principles of green methods. The sonochemical method eliminates the requirement for organic solvents, cross-linkers and hydrophobic agents used in the conventional miniemulsion technique. The method not only increases the reaction rate, but also leads to regular size distribution of the products. The composites are characterized by TEM, SAED, EDX, DLS, Z potential, FTIR and TGA. The biocompatibility of the synthesized materials has been studied in the light of protein adsorption, histopathology, haematological and non-thrombogenic property for probable use in the field of safe drug delivery. Bare silica nanoparticle has drug loading capability, but it lacks haemo-compatibility, tissue specificity and site directing ability.

Synthesis of novel aniline immobilized silica gel for the selective extraction of Cr(III)

AbstractAniline moiety was immobilized on the surface of silica gel (SG) through functionalizing the later by 3-chloropropyl trimethoxysilane (3-CPTS). The aniline immobilization was confirmed by chemical, Fourier transform infrared (FTIR), thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM). Solid phase extraction (SPE) property of the synthesized product was studied in terms of Cr(III) uptake by batch and column methods. Metal ion adsorption and its isotherm, kinetic and thermodynamic parameters were evaluated. The mechanistic path involved in up taking metal ion has been suggested. The Cr(III) binding capacity was found to be 8.7 mg g−1 at trace level of chromium in aqueous medium. The presence of chloride ion improved the metal ion binding capacity as well as selectivity to a significant extent. The developed material and the selective extraction method were tested by applying it in real samples and the results were compared with the reported values.

Selective Solid Phase Extraction of Chromium(VI) using Silica Gel Immobilized 4-vinyl Pyridine/Cupric Ion Complex

Immobilization of 4-vinyl pyridine (4-VP) onto silica gel (SG) and its coordination with cupric ion (SG-4-VP→Cu2+) leading to a new solid phase extractor has been carried out by a simple chemical technique. Immobilization and coordination reactions are characterized by chemical, FTIR, UV, and thermo-gravimetric analysis. The role of cupric ion on Cr(VI) binding capacity of the synthesized organic-inorganic hybrid material has been elucidated. The silica gel immobilized 4-VP/Cu2+ complex (hybrid material) is tested for selective extraction and pre-concentration of Cr(VI) from aqueous solution. The Cr(VI) binding behavior of the synthesized material is studied at different pH, time, and temperature of the medium in both competitive and non-competitive conditions.