Showing papers by "Swarup Roy published in 2014"

Spectroscopic studies of interaction between biologically synthesized silver nanoparticles and bovine serum albumin.

Abstract: Binding interaction of biologically synthesized silver nanoparticles with bovine serum albumin (BSA) has been investigated by UV-Vis and fluorescence spectroscopic techniques. UV-Vis analysis implies the formation of the ground state complex between BSA and silver nanoparticles. The analysis of fluorescence spectrum and fluorescence intensity indicates that silver nanoparticles (SNP) have a strong ability to quench the intrinsic fluorescence of BSA by dynamic quenching mechanisms. The number of binding sites 'n' and binding constants 'K' were determined at different temperatures based on fluorescence quenching. The thermodynamic parameters namely deltaH, deltaG, and deltaS were calculated at different temperatures (20, 30, and 40 degrees C) and the results indicate that both hydrophobic and electrostatic interactions were predominantly present in the SNP-BSA complex. Negative deltaG values imply that the binding process is spontaneous.

Spectroscopic Study of Interaction Between Extracellular Fungal Proteins and Biosynthe- sized Silver Nanoparticles

Abstract: Aspergillus foetidus have been used to synthesize biological silver nanoparticles and extracellular proteins were also isolated from the same strain. The interaction between fungal isolated protein and silver nanoparticles was investigated by UV- Vis spectroscopy, fluorescence spectroscopy and circular dichroism technique. UV- Vis spectroscopic data demonstrates that formation of the complex between fungal proteins and silver nanoparti- cles occur. Fluorescence spectrum results clearly suggest that silver nanoparticles have a strong ability to quench the intrinsic fluorescence of protein by quenching mechanisms. The number of binding sites 'n' and binding constants 'K' were calculated according to the relevant fluorescence data. Thermo- dynamic parameters ΔH, ΔG and ΔS were calculated at different temperatures and the results showed that Van der Waals force and hydrogen bonding played a major role. Negative ΔG values imply that the binding process is spontaneous. Circular dichroism results also revealed a conformational change.