Avinash P. Ingle

Silver nanoparticles: the powerful nanoweapon against multidrug‐resistant bacteria

In the present scenario, pharmaceutical and biomedical sectors are facing the challenges of continuous increase in the multidrug‐resistant (MDR) human pathogenic microbes. Re‐emergence of MDR microbes is facilitated by drug and/or antibiotic resistance, which is acquired way of microbes for their survival and multiplication in uncomfortable environments. MDR bacterial infections lead to significant increase in mortality, morbidity and cost of prolonged treatments. Therefore, development, modification or searching the antimicrobial compounds having bactericidal potential against MDR bacteria is a priority area of research. Silver in the form of various compounds and bhasmas have been used in Ayurveda to treat several bacterial infections since time immemorial. As several pathogenic bacteria are developing antibiotic resistance, silver nanoparticles are the new hope to treat them. This review discusses the bactericidal potential of silver nanoparticles against the MDR bacteria. This multiactional nanoweapon can be used for the treatment and prevention of drug‐resistant microbes.

Fungus-mediated synthesis of silver nanoparticles and their activity against pathogenic fungi in combination with fluconazole.

UNLABELLEDnSilver nanoparticles (Ag-NPs) are known to have inhibitory and bactericidal effects. Resistance of fungal infections has emerged in recent years and is a major health problem. Here, we report the extracellular biosynthesis of Ag-NPs using a common fungus, Alternaria alternata. Also in this study, these nanoparticles were evaluated for their part in increasing the antifungal activity of fluconazole against Phoma glomerata, Phoma herbarum, Fusarium semitectum, Trichoderma sp., and Candida albicans. The antifungal activity of fluconazole was enhanced against the test fungi in the presence of Ag-NPs. Fluconazole in combination with Ag-NPs showed the maximum inhibition against C. albicans, which was confirmed from the increase in fold area of inhibition, followed by P. glomerata and Trichoderma sp., which showed less increase in the fold area, whereas no significant enhancement of activity was found against P. herbarum and F. semitectum.nnnFROM THE CLINICAL EDITORnThe antifungal activity of fluconazole was enhanced in presence of silver nanoparticles against the test fungi. Fluconazole in combination with Ag-NPs showed the maximum inhibition against C. albicans, followed by P. glomerata and Trichoderma sp. No significant enhancement of activity was found against P. herbarum and F. semitectum.

Mycosynthesis of Silver Nanoparticles Using the Fungus Fusarium acuminatum and its Activity Against Some Human Pathogenic Bacteria

We report extracellular mycosynthesis of silver nanoparticles by Fusarium acuminatum Ell. and Ev. (USM-3793) isolated from infected ginger (Zingiber officinale). An aqueous silver nitrate solution was reduced to metallic silver when exposed to F. acumi- natum cell extract leading to the appearance of a brown color within 15-20 minutes. The color is due to the formation of silver nanoparti- cles and the excitation of surface plasmons. The optical spectrum showed the plasmon resonance at 420 nm and analysis by transmission electron microscopy confirmed the presence of silver nanoparticles. The nanoparticles produced were spherical with a broad size distribu- tion in the range of 5-40 nm with average diameter of 13 nm. The reduction of the silver ions occurs probably by a nitrate-dependent re- ductase enzyme, which we found to be present in the extra-cellular medium. We tested the silver particles for their broad-band antibacte- rial activity on different human pathogens. We observed efficient antibacterial activity against multidrug resistant and highly pathogenic bacteria, including multidrug resistant Staphylococcus aureus, Salmonella typhi, Staphylococcus epidermidis, and Escherichia coli. The synthesis of silver nanoparticles by the fungus F. acuminatum may therefore serve as a simple, cheap, eco-friendly, reliable and safe method to produce an antimicrobial material.

Fabrication of silver nanoparticles by Phoma glomerata and its combined effect against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus.

Aims:u2002 We report extracellular synthesis of silver nanoparticles (Ag‐NPs) from Phoma glomerata and its efficacy against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The bacteria exhibiting resistance to various antibiotics showed remarkable sensitivity, when used in combination of antibiotics and Ag‐NPs.

Role of nanotechnology in agriculture with special reference to management of insect pests

Nanotechnology is a promising field of interdisciplinary research. It opens up a wide array of opportunities in various fields like medicine, pharmaceuticals, electronics and agriculture. The potential uses and benefits of nanotechnology are enormous. These include insect pests management through the formulations of nanomaterials-based pesticides and insecticides, enhancement of agricultural productivity using bio-conjugated nanoparticles (encapsulation) for slow release of nutrients and water, nanoparticle-mediated gene or DNA transfer in plants for the development of insect pest-resistant varieties and use of nanomaterials for preparation of different kind of biosensors, which would be useful in remote sensing devices required for precision farming. Traditional strategies like integrated pest management used in agriculture are insufficient, and application of chemical pesticides like DDT have adverse effects on animals and human beings apart from the decline in soil fertility. Therefore, nanotechnology would provide green and efficient alternatives for the management of insect pests in agriculture without harming the nature. This review is focused on traditional strategies used for the management of insect pests, limitations of use of chemical pesticides and potential of nanomaterials in insect pest management as modern approaches of nanotechnology.

Silver Nanoparticles: Therapeutical Uses, Toxicity, and Safety Issues

The promises of nanotechnology have been realized to deliver the greatest scientific and technological advances in several areas. The biocidal activity of Metal nanoparticles in general and silver nanoparticles (AgNPs) depends on several morphological and physicochemical characteristics of the particles. Many of the interactions of the AgNPs with the human body are still poorly understood; consequently, the most desirable characteristics for the AgNPs are not yet well established. Therefore, the development of nanoparticles with well-controlled morphological and physicochemical features for application in human body is still an active area of interdisciplinary research. Effects of the development of technology of nanostructured compounds seem to be so large and comprehensive that probably it will impact on all fields of science and technology. However, mechanisms of safety control in application, utilization, responsiveness, and disposal accumulation still need to be further studied in-depth to ensure that the advances provided by nanotechnology are real and liable to provide solid and consistent progress. This review aims to discuss AgNPs applied in biomedicine and as promising field for insertion and development of new compounds related to medical and pharmacy technology. The review also addresses drug delivery, toxicity issues, and the safety rules concerning biomedical applications of silver nanoparticles.

Enhanced antimicrobial activity of silver nanoparticles synthesized by Cryphonectria sp. evaluated singly and in combination with antibiotics

UNLABELLEDnThe newly identified pathogenic species of the genus Cryphonectria was exploited for the synthesis of silver nanoparticles (AgNPs). The extracellular synthesis of nanoparticles was fast and eco-friendly. These nanoparticles were analyzed and determined by ultraviolet-visible spectrophotometry, which detected AgNPs in the solution, and by NanoSight LM20, which determined their average size and concentration. The synthesized AgNPs showed a little monodispersity in the range of 30-70 nm with a concentration of 6.82 × 10(8) particles per milliliter of solution. The AgNPs demonstrated antibacterial activity against Staphylococcus aureus, Escherichia coli, Salmonella typhi, and Candida albicans, with comparatively higher activity against both S. aureus and E.xa0coli than against S. typhi and C. albicans, which showed the lowest activity. The present study demonstrates the possible use of biologically synthesized AgNPs in the field of medicine. Thus, Cryphonectria sp. could be used for simple, nonhazardous, and efficient synthesis of AgNPs.nnnFROM THE CLINICAL EDITORnIn this study Cryphonectria sp. was exploited for simple, nonhazardous, and efficient biosynthesis of silver nanopartricles, which had antibacterial activity against a variety of human pathogenic bacteria.

Broad-spectrum bioactivities of silver nanoparticles: the emerging trends and future prospects.

There are alarming reports of growing microbial resistance to all classes of antimicrobial agents used against different infections. Also the existing classes of anticancer drugs used against different tumours warrant the urgent search for more effective alternative agents for treatment. Broad-spectrum bioactivities of silver nanoparticles indicate their potential to solve many microbial resistance problems up to a certain extent. The antibacterial, antifungal, antiviral, antiprotozoal, acaricidal, larvicidal, lousicidal and anticancer activities of silver nanoparticles have recently attracted the attention of scientists all over the world. The aim of the present review is to discuss broad-spectrum multifunctional activities of silver nanoparticles and stress their therapeutic potential as smart nanomedicine. Much emphasis has been dedicated to the antimicrobial and anticancer potential of silver nanoparticles showing their promising characteristics for treatment, prophylaxis and control of infections, as well as for diagnosis and treatment of different cancer types.

Bioactivity, mechanism of action, and cytotoxicity of copper-based nanoparticles: A review

Nanotechnology is an emerging branch of science, which has potential to solve many problems in different fields. The union of nanotechnology with other fields of sciences including physics, chemistry, and biology has brought the concept of synthesis of nanoparticles from their respective metals. Till date, many types of nanoparticles have been synthesized and being used in different fields for various applications. Moreover, copper nanoparticles attract biologists because of their significant and broad-spectrum bioactivity. Due to the large surface area to volume ratio, copper nanoparticles have been used as potential antimicrobial agent in many biomedical applications. But the excess use of any metal nanoparticles increase the chance of toxicity to humans, other living beings, and environment. In this article, we have critically reviewed the bioactivities and cytotoxicity of copper nanoparticles. We have also focused on possible mechanism involved in its interaction with microbes.

Synthesis of Silver Nanoparticles Using Callus Extract of Carica papaya — A First Report

This is the first report of synthesis of silver nanoparticles by using callus extract of Carica papaya. MS medium supplemented with the growth hormones, 2.0 mg l−1 IBA and 0.5 mg l−1 BAP was found to be more suitable for the induction of callus and multiple shoots in papaya. The extract of callus obtained by grinding showed ability of synthesis of silver nanoparticles when treated with silver nitrate (1 mM). The formation of brown colour in the reaction mixture indicates the synthesis of silver nanoparticles. The further detection and characterization of these synthesized silver nanoparticles was carried by spectrophotometry. FTIR spectrum analysis showed peaks between 1000–2000 cm−1 which confirmed the presence of proteins and other ligands required for the synthesis and stabilization of silver nanoparticles. SEM micrograph confirmed the synthesis of spherical silver nanoparticles in the size range of 60–80 nm.