TheBombyx morisilk fibroin (SF) films were prepared by solution casting method and effects of electron beam on the optical properties and optical constants of the films have been studied by using UV-Visible spectrophotometer. Optical properties like optical band gapEg, refractive indexn, extinction coefficientk, optical conductivityσopt, and dielectric constantsε∗of virgin and electron irradiated films were determined by using UV-Visible absorption and transmission spectra. It was found that the reduction in optical band gap and increase in refractive index with increasing radiation dosage was observed. It is also observed from results that there is increase in dielectric constants with increasing photon energy. The observed optical changes have been tried to be correlated with the structural changes, revealed through FT-IR spectroscopy. The present study is quite important for tailoring the optical responses of SF films as per specific requirements.

The silver nanoparticles were synthesized (AgNPs) under incandescent light at room temperature using aqueous silk fibroin obtained from Bombyx mori silk used as green stabilizer. The formation of colloidal AgNPs were determined and confirmed by different characterization techniques i.e. UVvisible spectroscopy, transmission electron microscope (TEM), dynamic light scattering and EDAX. The UV-visible spectroscopy showing a characteristic surface plasmon resonance band at 432 nm. The FTIR spectra confirms the presence of functional groups, the TEM images confirmed that the synthesized nanoparticles were spherical in shape with smooth surfaces. The particle diameter was around 35-40 nm. Further, the x-ray diffraction analysis confirms the nanocrystalline phase of silver with face centered cubic crystal structure. The synthesized colloidal silver nanoparticles exhibits potential antibacterial activity against Gram positive and Gram negative bacteria i.e. Bacillus subtilis, Staphylococcus aureus, Salmonella typhi and Escherichia coli.

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This research paper describes the fabrication of bionanocomposites (BNCs) based on silk fibroin (SF) and reduced graphene oxide (rGO). The recorded UV–visible (UV–vis) spectra of the sample confirm the reduction of GO to rGO in SF by showing a plasmon resonance band within the wavelength range of 261–268 nm. The X-ray diffraction (XRD) peak at 11.6° corresponding to the GO intensity decreases with increasing reaction time, resulting in rGO in the SF host matrix. The morphological behavior of the SF–rGO BNCs is scrutinized using scanning electron microscopy (SEM), and the images clearly indicate the existence of rGO within the matrix. The increasing amount of GO in the SF shows broken graphene sheets, which can increase the surface roughness and establish a strong physical contact between the SF and rGO nanosheets. The high-resolution transmission electron microscope (HR-TEM) image of the bionanocomposite showed that the formed rGO encompassments of fewer layers are stacked, each with fewer wrinkles and folding. The Raman spectroscopy confirmed the formation of rGO by showing the increased intensity ratio of D to G band (I D/I G) in the bionanocomposite samples. The rGO effect on the electrical conductivity is measured, and the results show that DC conductivity increases from 1.28 × 10–9 to 82.4 × 10–9 S/cm with an increase in the GO content in the SF biopolymer. The investigations demonstrate loss of the insulation property and improved conducting behavior of the SF biopolymer.

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