Effects of high energy electrons on physical and tensile properties of non-mulberry silk fibers

Tassar silk fiber (Antheraea mylitta) was irradiated with the available maximum dose range upto 100 kGy using 8 MeV electron beam at room temperature. Irradiation effect in these fibers is quantified in terms of the changes in microstructural parameters studied using wide-angle X-ray scattering data (WAXS). The crystal imperfection parameters such as crystallite size (<N>), lattice strain (g in %), and surface weighted crystallite size (D s in à ) have been determined by line profile analysis (LPA) using Fourier method of Warren. For this purpose, exponential, lognormal, and Reinhold functions for column length distribution have been used for the determination of these parameters. These parameters were compared with tensile properties of the fibers. The increasing trend of crystallite size values (<N> as well as D s in à ) and tenacity (gf/den) with increasing dosage of radiation clearly indicates the cross linking polymer network in fiber. Comparison of SEM photographs also confirms the X-ray results

Rapid synthesis of gold nanoparticles using silk fibroin: characterization, antibacterial activity, and anticancer properties

In the present work, well-dispersed gold nanoparticles (AuNPs) were synthesised by the reduction of HAuCl4.xH2O using silk fibroin as a reducing agent. UV-visible spectroscopy confirmed the formation of AuNPs by showing surface plasmon resonance (SPR) at 526--518 nm. The FT-IR study revealed that the hydroxyl groups in the Tyr residue and the carboxyl groups in the Asp and/or Glu residues were the most active functional groups for the conversion of Au ion reduction. The transmission electron microscope (TEM) images showed that the formed nanoparticles were uniformly embedded in the silk fibroin solution. The AuNPs are spherical in shape with smooth edges and around 5--8 nm in diameter. Also, these possess very good stability and dispersity and can be stored for a long period. Further, the X-ray diffraction (XRD) study confirmed the nanocrystalline phase of the gold with cubic crystal structure. The biogenic gold nanoparticles displayed antibacterial activity against Gram-positive and Gram-negative bacteria, and also showed promising anticancer properties