Department of Biological Sciences

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Author: search.filters.author.Panwar, JitendraSubject: search.filters.subject.Nanoparticles

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    Bacterial Synthesis of Metallic Nanoparticles
    (Taylor & Francis, 2019) Panwar, Jitendra
    There is growing need to develop clean, non-toxic and environmentally friendly (“green chemistry”) procedures for synthesis and assembly of nanoparticles (NPs). The use of biological organisms in this area is rapidly gaining importance due to their ecological significance, high success rates and ease in formation of nanoparticles. The advantages associated with the use of microorganisms, for biosynthesis of metal NPs, have attracted researchers to elucidate the mechanisms of metal ion uptake, its bioreduction, NP formation and decipher the role of microbial enzymes in the formation of NPs. Bacteria have been known to enrich ions, synthesize magnetite crystals, reduce Ag+ into metal particles, form nanoparticles as well as octahedral gold and, recently, ceramic to metal composites. This review focuses on the effective and efficient synthesis of metallic nanoparticles by bacteria while exploring their various prospective applications, as nanofertilizers and plant protectants, besides trying to understand the current scenario in the debates on the toxicity issues of these nanoparticles.
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    Superior Bactericidal Efficacy of Fucose-Functionalized Silver Nanoparticles against Pseudomonas aeruginosa PAO1 and Prevention of Its Colonization on Urinary Catheters
    (ACS, 2018-08-10) Panwar, Jitendra
    Pseudomonas aeruginosa, a Gram-negative rod-shaped bacterium is a notorious pathogen causing chronic infections. Its ability to form antibiotic-resistant biofilm has raised the need for the development of alternative treatment approaches. An ideal alternate can be silver nanoparticles known for their strong yet tunable bactericidal activity. However, their use in commercial in vivo medicine could not see the light of the day because of the unwanted toxicity of silver in the host cells at higher concentrations. Thus, strategies which can modulate the bacterial cell–silver nanoparticle interactions thereby reducing the amount of nanoparticles required to kill a typical number of bacterial cells are utmost welcomed. The current work showcases one such strategy by functionalizing the silver nanoparticles with l-fucose to increase their interactions with the LecB lectins present on P. aeruginosa PAO1. The advantage of this approach lies in the higher bactericidal and antibiofilm activity of fucose-functionalized silver nanoparticles (FNPs) as compared to the citrate-capped silver nanoparticles (CNPs) of similar size and concentrations. The superior bactericidal potential of FNPs as demonstrated by fluorescence-assisted cell sorting, confocal laser scanning microscopy, and transmission electron microscopy analyses may be attributed to the higher reactive oxygen species generation and oxidative membrane damage. Additionally, FNPs prevented the formation of biofilms by downregulating the expression of various virulence genes at lower concentrations as compared to CNPs. The practical applicability of the approach was demonstrated by preventing bacterial colonization on artificial silicone rubber surfaces. These results can be extrapolated in the treatment of catheter-associated urinary tract infections caused by P. aeruginosa. In conclusion, the present work strongly advocates the use of antivirulence targets and their corresponding binding residues for the augmentation of the bactericidal effect of silver nanoparticles.
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    Biogenic Synthesis of Metallic Nanoparticles by Plant Extracts
    (ACS, 2013-04) Panwar, Jitendra
    In recent years, nanobiotechnology has emerged as an elementary division of modern science and a noval epoch in the fields of material science and is receiving global attention due to its ample applications. Various physical, chemical, and biological methods have been employed to synthesize nanomaterials. Biological systems such as bacteria, fungi, actinomycetes, yeasts, viruses, and plants have been reported to synthesize various metal and metal oxide nanoparticles. Among these, biosynthesis of nanoparticles from plants seems to be a very effective method in developing a rapid, clean, nontoxic, and eco-friendly technology. The use of plant biomass or extracts for the biosynthesis of novel metal nanoparticles (silver, gold, platinum, and palladium) would be more significant if the nanoparticles are synthesized extracellularly and in a controlled manner according to their dispersity of shape and size. Owing to the rich biodiversity of plants, their potential use toward the synthesis of these nobel metal nanoparticles is yet to be explored. The aim of this review is to provide the recent trends involved in the phytosynthesis of nobel metal nanoparticles in the past decade.