ABSTRACT
In the present work we studied the effect of 2D WS2 nanoparticles on the conformational changes in lysozyme protein at different pH values (2.0-11.5). The contributions of various structural conformations (α-helix, ß-sheets parallel and antiparallel, unordered structure and side groups) were determined by decomposition of Amid I absorbance bands. The 2D WS2 were shown to have different impact on secondary structure depending on pH of the solution and protein concentration. The amyloid fibril presence was confirmed with confocal microscopy enhanced by gold support, and fluorescent spectroscopy with amyloid-sensitive dye Thioflavin T. Our data show that WS2 can both inhibit and stimulate amyloid formation. Additionally, we have also reported an unusual spectroscopic behavior displayed by lysozyme, indicated by narrowing of Amide I and Amide II bands at pH 2.5 and 3.5 when incubated with 2D WS2 nanoparticles.
Subject(s)
Amyloid/chemistry , Metal Nanoparticles/chemistry , Muramidase/chemistry , Sulfides/chemistry , Tungsten Compounds/chemistry , Animals , Benzothiazoles/chemistry , Chickens , Egg White/chemistry , Fluorescent Dyes/chemistry , Hydrogen-Ion Concentration , Protein Conformation, alpha-Helical , Protein Conformation, beta-Strand , Spectrum Analysis/methodsABSTRACT
The development of the nanomaterials with the advanced functional characteristics is a challenging task because of the growing demand in the market of the optoelectronic devices, biodegradable plastics, and materials for energy saving and energy storage. Nanocellulose is comprised of the nanosized cellulose particles, properties of which depend on characteristics of plant raw materials as well as methods of nanocellulose preparation. In this study, the effect of the mechanochemical treatment of bleached softwood sulfate pulp on the optical and mechanical properties of nanocellulose films was assessed. It was established that the method of the subsequent grinding, acid hydrolysis and ultrasound treatment of cellulose generated films with the significant transparency in the visible spectral range (up to 78 % at 600 nm), high Young's modulus (up to 8.8 GPa), and tensile strength (up to 88 MPa) with increased ordering of the packing of the cellulose macromolecules. Morphological characterization was done using the dynamic light scattering (DLS) analyzer and transmission electron microscopy (TEM). The nanocellulose particles had an average diameter of 15-30 nm and a high aspect ratio in the range 120-150. The crystallinity was increased with successive treatments as shown by the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. The thermal degradation behavior of cellulose samples was explored by thermal gravimetric analysis (TGA).
