A comparative study on biologically and chemically synthesized silver nanoparticles induced Heat Shock Proteins on fresh water fish Oreochromis niloticus.

The wide applicability of silver nanoparticles in medicine and pharmaceutical industries leads to its over exploitation and thus contaminating our environment. Majority of these nanoscale dimension particles finally accumulates in fresh water and marine ecosystem. As the nanoparticles behave entirely different from its corresponding bulk material, a better understanding of their environmental impacts in aquatic ecosystems is inevitable. The study was focused on a comparative stress physiology analysis of chemically synthesized silver nanoparticles and biogenic silver nanoparticles. Half maximal inhibitory concentration of biologically synthesized and chemically synthesized nanoparticles was found out (30µg/mL and 20µg/mL respectively). The Heat Shock Protein (HSP70) secretion was analysed in the fresh water fish Oreochromis niloticus after exposing to different concentrations of biologically and chemically synthesized silver nanoparticles along with the silver in its ionic form. The intense immune-histochemical staining of fish tissues (muscle, kidney and liver) analyzed proportionately reflected the stress created. The colour intensity was directly proportional to the stress created or the stress protein released. High level of HSP70 expression was observed in all of the fish tissues exposed to silver ions and chemically synthesized silver nanoparticles, when compared to that of biologically synthesized. The results revealed the significance of comparatively safe and less toxic biogenic nanoparticles compared to the chemically synthesized.

Augmentation of PCR efficiency using highly thermostable gold nanoparticles synthesized from a thermophilic bacterium, Geobacillus stearothermophilus.

Biogenic gold nanoparticles were synthesized from the Geobacillus stearothermophilus cell-free extract. These nanoparticles were characterized by UV-vis spectroscopy, FTIR, TEM, and XRD. The gold nanoparticles showed an absorption maximum at 522 nm. The TEM micrograph revealed the formation of monodispersed particles. The high degree of stability of the nanoparticle solution could be attributed to the secretion of certain capping proteins by the bacterium in the reaction mixture which was confirmed by the FTIR and UV-vis spectrometric analyses. The heat transfer property of the gold nanoparticles in aqueous solution has been explored in the current study for augmenting the PCR efficiency. The highly thermostable biogenic gold nanoparticles effectively increased the yield, product specificity besides reducing the reaction time of the PCR.

Biosynthesis of anisotropic gold nanoparticles using Maduca longifolia extract and their potential in infrared absorption.

Metal nanoparticles, in general, and gold nanoparticles, in particular, are very attractive because of their size- and shape-dependent properties. Biosynthesis of anisotropic gold nanoparticles using aqueous extract of Madhuca longifolia and their potential as IR blockers has been demonstrated. The tyrosine residue was identified as the active functional group for gold ion reduction. These gold nanoparticles were characterized by of UV-Vis spectrophotometer, FTIR, TEM and HrTEM. The presence of proteins was identified by FTIR, SDS-PAGE, UV-Vis and fluorescence spectroscopy. The micrograph revealed the formation of anisotropic gold nanoaprticles. The biologically synthesized gold nanotriangles can be easily coated in the glass windows which are highly efficient in absorbing IR radiations.

Mycobased synthesis of silver nanoparticles and their incorporation into sodium alginate films for vegetable and fruit preservation.

Biosynthesis of silver nanoparticles using Trichoderma viride and their incorporation into sodium alginate for vegetable and fruit preservation has been demonstrated in this study. Aqueous silver (Ag(+)) ions when exposed to the filtrate of T. viride are reduced in solution. These extremely stable silver nanoparticles were characterized by means of UV-vis spectrophotometer, FTIR, TEM, and EDS. The nanoparticles exhibit maximum absorbance at 421 nm in the UV spectrum. The presence of proteins was identified by FTIR. TEM micrograph revealed the formation of polydispersed nanoparticles, and the presence of elemental silver was confirmed by EDS analysis. The silver nanoparticle incorporated sodium alginate thin film shows good antibacterial activity against test strains. This film increases the shelf life of carrot and pear when compared to control with respect to weight loss and soluble protein content. These results show silver nanoparticle incorporated sodium alginate coated vegetables and fruits are suitable for preservation.