Sneha Singh

Bio: Sneha Singh is an academic researcher from Birla Institute of Technology, Mesra. The author has contributed to research in topics: Colloidal gold & Nanoparticle. The author has an hindex of 5, co-authored 20 publications receiving 115 citations. Previous affiliations of Sneha Singh include Birla Institute of Technology and Science.

Extracellular facile biosynthesis, characterization and stability of gold nanoparticles by Bacillus licheniformis

Abstract: Context: The development of a reliable, eco-friendly process for synthesis of gold nanoparticles (AuNPs) has gained impetus in recent years to counter the drawbacks of chemical and physical methods. Objective: This study illustrates simple, green synthesis of AuNPs in vitro using cell lysate supernatant (CLS) of non-pathogenic bacteria and to investigate its potential antimicrobial activity. Materials and methods: Gold nanoparticles were synthesized by the reduction of precursor AuCl4− ions using the CLS of Bacillus licheniformis at 37°C upon 24 h of incubation. The nanoparticles were characterized for their morphology, particle size, optical absorption, zeta potential, and stability. Further the antimicrobial activity was assayed using cup-plate method. Results: The process of biosynthesis was extracellular and the gold ions were reduced to stable nanogold of average size 38 nm. However, upon storage of AuNPs for longer duration at room temperature stability was influenced in terms of increase in...

"Oral Vaccine Antigen Induced Immune Response Signalling Pathways: Current and Future Perspectives"

Abstract: Vaccination is the most promising approach to control and prevent the infectious diseases. As most of pathogenic microrganisms gain entry through the mucosal surfaces of host which provide great deal of interest in developing oral vaccines. Despite the success of many vaccines, only little information is available regarding the oral vaccine antigen induced immunogenic signalling pathways. Such information will be helpful to design future vaccines against old and new infectious diseases to reduce the side effects of existing vaccines and increase their efficacy. In this review, the oral vaccine antigen inducing complex signaling pathways of immune system has been discussed. Various stra

Metal-based nanoparticles as antimicrobial agents: an overview.

Abstract: Metal-based nanoparticles have been extensively investigated for a set of biomedical applications. According to the World Health Organization, in addition to their reduced size and selectivity for bacteria, metal-based nanoparticles have also proved to be effective against pathogens listed as a priority. Metal-based nanoparticles are known to have non-specific bacterial toxicity mechanisms (they do not bind to a specific receptor in the bacterial cell) which not only makes the development of resistance by bacteria difficult, but also broadens the spectrum of antibacterial activity. As a result, a large majority of metal-based nanoparticles efficacy studies performed so far have shown promising results in both Gram-positive and Gram-negative bacteria. The aim of this review has been a comprehensive discussion of the state of the art on the use of the most relevant types of metal nanoparticles employed as antimicrobial agents. A special emphasis to silver nanoparticles is given, while others (e.g., gold, zinc oxide, copper, and copper oxide nanoparticles) commonly used in antibiotherapy are also reviewed. The novelty of this review relies on the comparative discussion of the different types of metal nanoparticles, their production methods, physicochemical characterization, and pharmacokinetics together with the toxicological risk encountered with the use of different types of nanoparticles as antimicrobial agents. Their added-value in the development of alternative, more effective antibiotics against multi-resistant Gram-negative bacteria has been highlighted.

A strategic approach for rapid synthesis of gold and silver nanoparticles by Panax ginseng leaves.

Abstract: The study highlights the synthesis of gold nanoparticles and silver nanoparticles by fresh leaves of Panax ginseng, an herbal medicinal plant. The reduction of auric chloride and silver nitrate led to the formation of gold and silver nanoparticles within 3 and 45 min, at 80°C, respectively. The developed methodology was rapid, facile, ecofriendly and the utmost significant is quite economical, which did not require subsequent processing for reduction or stabilization of nanoparticles. The nanoparticles were further characterized by Ultraviolet-visible spectroscopy (UV-vis) which showed the relevant peak for gold and silver nanoparticles at 578 and 420 nm, correspondingly. Field-emission transmission electron microscopy (FE-TEM) displayed the spherical shape of monodispersed nanoparticles. FE-TEM revealed that the gold nanoparticles were 10-20 nm and silver nanoparticles were 5-15 nm. The energy dispersive X-ray (EDX) and elemental mapping results indicated the maximum distribution of gold and silver elements in the respective nanoproducts, which further corresponds the purity. Further, the X-ray diffraction (XRD) results confirm the crystalline nature of synthesized nanoparticles. The biosynthesized AgNPs served as an efficient antimicrobial agent at 3 μg concentration against many pathogenic strains for instance, Escherichia coli, Salmonella enterica, Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus anthracis and Bacillus cereus. In addition, AgNPs showed complete inhibition of biofilm formation by S. aureus and Pseudomonas aeruginosa at 4 μg/ml concentration. Moreover, the AuNPs and AgNPs found as a potent anticoagulant agent. Thus, the study claims the rapid synthesis of gold and silver nanoparticles by fresh P. ginseng leaf extract and its biological applications.

The Review of Natural Products

Abstract: The Review of Natural Products is the foremost source of current natural product information for health care professionals. More than 350 in-depth monographs are included, based on scientific research, not just anecdotal information. The Review of Natural Products provides detailed information about natural products, including their botany, history, chemistry, pharmacology, medicinal uses, toxicology, and patient information. It also includes significantly documented drug interactions.Provides up-to-date, objective assessment of the latest medical and scientific studies on natural products, including medically active foods (nutraceuticals).