Study of the structure of degummed Antheraea assamensis (muga) silk fibre

The paper discusses a special type of silk (muga silk) produced by the moth Antheraea assamensis (Lepidoptera: Saturniidae), which is available in the north east region, particularly in Assam, India. The structure of the degummed muga silk fibre is characterised by spectroscopy and X‐ray diffraction. An attempt has been made to establish a correlation between the orientation of the protein of the fibre and the mechanical properties of the fibre. Inter‐conversion of the α‐ and β‐phases of proteins is very common, and in some cases, both the phases may be present. Since muga silk is a protein fibre, there is a strong possibility of exhibition of this inter‐conversion property. The results show that the structure of muga fibre is made up of four molecular chains contained in a primitive tetrahedral cell with an average cell edge a _o = b ₀ = 746 pm and c ₀ =738 pm (fibre axis) and lattice number 8. The space group of the α‐phase is P4₁, with screw axis 4₁. The α‐phase accounts for rigidity and crystallinity, while the β‐phase accounts for extensibility and the amorphous state of the fibre.     

Impact of BSA and casein on chemical modification of muga silk fiber

The study reports on the effects of bovine serum albumin and casein on grafting of muga (Antheraea assamensis Helfer) silk fibers using initiator 2,2’ azobisisobutyronitrile. FTIR studies confirm the chemical binding of the proteins onto muga fibers through shifting of the major amide bonds, accredited to grafting. Scanning electron microscopy imaging reveals rugged morphology of the grafted fibers, due to the imprints of granular proteins. Tensile strength of the fibers increases with the augmentation in grafting percent. The grafted fibers showed no loss in weight after chemical resistance measurement indicating stable bond formation between the proteins and the fibers. Moreover, the water retention capacity and dynamic contact angle study of grafted fibers suggest better hydrophobicity. Thus, the use of such eco-friendly grafting agents for enhancing the strength and stability of silk fiber proves to be more beneficial than to other chemical grafting agents in producing efficient and environment-friendly silk for various applications in textile and other biomaterial fields.     

Preparation of networked polymer electrolytes by copolymerization of a methacrylate with an imidazolium salt structure and an ethyleneglycol dimethacrylate in the presence of lithium bis(trifluoromethanesulfonyl)imide

Ionic networked polymers containing ionic liquids were synthesized by radical copolymerization of 1-(2-methacryloyl)ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (Met-IL) and difunctional or trifunctional methacrylate cross-linkers, ethylene glycol dimethacrylate (EGDMA), or trimethylolpropane trimethacrylate (TMPTMA) in the presence of an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMImTFSI). For comparison, nonionic networked polymers containing the ionic liquid were prepared by radical copolymerization of methyl methacrylate (MMA) with EGDMA in the presence of EMImTFSI. Met-IL/EGDMA/EMImTFSI(50) showed higher ion conductivity and ionic liquid holding ability than the corresponding MMA/EGDMA/EMImTFSI(50), while Met-IL/TMPTMA/EMImTFSI(50) showed lower ionic conductivity with higher holding ability than MMA/EGDMA/EMImTFSI(50).     

Rational Design of a Cu Chelator That Mitigates Cu-Induced ROS Production by Amyloid Beta

Alzheimer's disease severely perturbs transition metal homeostasis in the brain leading to the accumulation of excess metals in extracellular and intraneuronal locations. The amyloid beta protein binds these transition metals, ultimately causing severe oxidative stress in the brain. Metal chelation therapy is an approach to sequester metals from amyloid beta and relieve the oxidative stress. Here we have designed a mixed N/O donor Cu chelator inspired by the proposed ligand set of Cu in amyloid beta. We demonstrate that the chelator effectively removes Cu from amyloid beta and suppresses reactive oxygen species (ROS) production by redox silencing and radical scavenging both in vitro and in cellulo. The impact of ROS on the extent of oxidation of the different aggregated forms of the peptide is studied by mass spectrometry, which, along with other ROS assays, shows that the oligomers are pro-oxidants in nature. The aliphatic Leu34, which was previously unobserved, has been identified as a new oxidation site.