Antibacterial and catalytic activity of biogenic gold nanoparticles synthesised by Trichoderma harzianum.

This study reveals the antibacterial and catalytic activity of biogenic gold nanoparicles (AuNPs) synthesised by biomass of Trichoderma harzianum. The antibacterial activity of AuNPs was analysed by the means of growth curve, well diffusion and colony forming unit (CFU) count methods. The minimum inhibitory concentration of AuNPs was 20 µg/ml. AuNPs at 60 µg/ml show effective antibacterial activity as optical absorption was insignificant. The well diffusion and CFU methods were also applied to analyse the effect of various concentration of AuNPs. Further, the catalytic activity of AuNPs was analysed against methylene blue (MB) as a model pollutant in water. MB was degraded 39% in 30 min in the presence of AuNPs and sodium borohydrate and the rate constant (k) was found to be 0.2 × 10-3 s-1. This shows that the biogenic AuNP is an effective candidate for antibacterial and catalytic degradation of toxic pollutants.

Catalytic degradation of methylene blue by biosynthesised copper nanoflowers using F. benghalensis leaf extract.

This study reports the unprecedented, novel and eco-friendly method for the synthesis of three-dimensional (3D) copper nanostructure having flower like morphology using leaf extract of Ficus benghalensis. The catalytic activity of copper nanoflowers (CuNFs) was investigated against methylene blue (MB) used as a modal dye pollutant. Scanning electron micrograph evidently designated 3D appearance of nanoflowers within a size range from 250 nm to 2.5 µm. Energy-dispersive X-ray spectra showed the presence of copper elements in the nanoflowers. Fourier-transform infrared spectra clearly demonstrated the presence of biomolecules which is responsible for the synthesis of CuNFs. The catalytic activity of the synthesised CuNFs was monitored by ultraviolet-visible spectroscopy. The MB was degraded by 72% in 85 min on addition of CuNFs and the rate constant (k) was found to be 0.77 × 10-3 s-1. This method adapted for synthesis of CuNFs offers a valuable contribution in the area of nanomaterial synthesis and in water research by suggesting a sustainable and an alternative route for removal of toxic solvents and waste materials.

Fungal biomolecules assisted biosynthesis of Au-Ag alloy nanoparticles and evaluation of their catalytic property.

The catalytic reduction of methylene blue was studied using biosynthesised gold-silver (Au-Ag) alloy nanoparticles (NPs). The fungal biomass of Trichoderma harzianum was used as a reducing and stabilising agent in the synthesis of Au-Ag alloy NPs. The synthesised NPs were well characterised by UV-vis spectroscopy, dynamic light scattering, X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The plausible synthesis mechanism involved in the formation of Au-Ag alloy NPs was also discussed with diagrammatic representation. A series of experiments was performed to investigate the catalytic activity of the as-prepared Au-Ag alloy NPs and found that the alloy NPs show excellent catalytic activity.

Biogenic gold nanoparticles: As a potential candidate for brain tumor directed drug delivery.

Gold nanoparticles have tremendous application in the area of nanotechnology that raises new possibility in the treatment of brain tumor. These nanoparticles can be used for selectively gaining access to tumor due to their small size and modifiability. Gold nanoparticles are functionalized with various molecules such as anticancer drug, transferrin and monoclonal antibody to produce nanocarriers. These nanocarriers have ability to deliver the drug at targeted site. Transferrin crosses the blood-brain barrier because of the receptor-mediated endocytosis. The monoclonal antibody facilitates the release of anticancer drug at targeted sites. This approach of delivery saves the normal cells surrounding the tumor.

ZnO nanoflowers: novel biogenic synthesis and enhanced photocatalytic activity.

We demonstrate a novel, unprecedented and eco-friendly mode for the biosynthesis of zinc oxide (ZnO) nanoflowers at ambient room temperature using Bacillus licheniformis MTCC 9555 and assessed their photocatalytic activity. The photocatalytic degradation of methylene blue (MB) dye was analyzed under UV-irradiation. An enhanced photocatalytic activity of ZnO nanoflowers was obtained compared to the earlier reports on ZnO nanostructures and other photocatalytic materials. The mechanism behind the enhanced photocatalytic activity was illustrated with diagrammatic representation. It is assumed that due to larger content of oxygen vacancy ZnO nanoflowers shows enhanced photocatalytic activity. Photostability of ZnO nanoflowers was analyzed for consecutive 3 cycles. The size and morphology of ZnO nanoflowers have been characterized by SEM, TEM and found to be in the size range of 250 nm to 1 µm with flower like morphology. It was found that ZnO nanoflowers was formed by agglomeration of ZnO nanorods. Further the EDX established the presence of the elemental signal of the Zn and O. XRD spectrum of ZnO nanoflowers confirmed 2θ values analogous to the ZnO nanocrystal. FTIR analysis was carried to determine the probable biomolecules responsible for stabilization of ZnO nanoflowers. The plausible mechanism behind the synthesis of ZnO nanoflowers by Bacillus licheniformis MTCC 9555 was also discussed with diagram representation.

Kinetic studies of L-asparaginase from Penicillium digitatum.

L-Asparaginase is an enzyme used in the treatment of acute lymphoblastic leukemia and other related malignancies. Its further use includes reduction of asparagine concentration in food products, which may lead to formation of acrylamide. Currently bacterial asparaginase is produced at industrial scale, but the enzyme isolated from bacterial origin is often associated with adverse reactions. These side effects require development of asparaginase from alternative sources. In the present study, Penicillium digitatum was explored for the production of extracellular L-asparaginase using modified Czapek-Dox media. The enzyme was purified about 60.95-fold and then kinetic study showed that the Km value of the enzyme was 1 × 10⁻5 M. The optimum pH and temperature for the enzyme were 7.0 and 30°C, respectively. The optimum incubation period for L-asparaginase was 15 min. This work concludes that this enzyme can be a suitable candidate due to its strong kinetic properties, and further research can usher into development of asparaginase formulation from fungal origin with less adverse effects.

Prevalence of Dental Caries among the Population of Gwalior (India) in Relation of Different Associated Factors.

OBJECTIVES: India is unique in entire world due to variety of dietary habits in population. Many people of India follow totally vegetarian life style through their entire life time due to some religious and cultural reasons. Present study tried to analyze the role of different factors in the occurrence of dental caries including dietary habit. METHODS: Persons suffering with dental caries were examined for the type of dental caries in relation to different factors. Dental examination was performed and patients were asked a questionnaire and the data was recorded and analyzed. RESULTS: Incidence of dental caries was higher in female. High number of dental caries patients was observed among vegetarian population. 21-30 year age group was found to be most infected with dental caries. CONCLUSIONS: This study can be helpful to analyze respective role of different dietary factors including protein rich diet, age, gender etc. on the prevalence of dental caries, which can be helpful to counteract the potential increase in the cases of dental caries and to design and plan preventive strategies for the persons at greatest risk.