muramidase and tetraethoxysilane

Fe

Topics: Adsorption; Animals; Chickens; Egg White; Ferric Compounds; Hydrogen-Ion Concentration; Kinetics; Magnetic Iron Oxide Nanoparticles; Metal Nanoparticles; Microscopy, Electron, Transmission; Muramidase; Serum Albumin, Bovine; Silanes; Thermogravimetry

Carboxyl-modified SBA-15 rod-like mesoporous materials have been synthesized by a facile rapid co-condensation of tetraethylorthosilicate (TEOS) and 2-cyanoethyltriethoxysilane (CTES), followed by hydrolysis of cyanide groups in sulfuric acid. The concentration of carboxylic groups was varied by changing the silica source ratio of CTES/TEOS from 0.05 to 0.3. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the uniform ordered mesoporous structure and rod-like morphology of SBA-15 have been preserved even at the high concentration of carboxylic groups employed. Characterization by Fourier transformed infrared spectroscopy (FTIR), solid-state NMR investigation indicated that carboxylic groups have been successfully grafted onto the surface of SBA-15 through siloxane bonds [(O(3))SiCH(2)CH(2)COOH. The negative charges of the modified SBA-15 materials were enhanced by the presence of the carboxylic groups on the surface. The capacity of lysozyme adsorption of the modified SBA-15 materials were found to be significantly improved as compared with pure silica SBA-15. The maximum amount of lysozyme adsorption on carboxyl-modified was increased with the pH of solution increased from 5.5 to 9.0.

Topics: Adsorption; Carboxylic Acids; Magnetic Resonance Spectroscopy; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Molecular Structure; Muramidase; Nitriles; Silanes; Silicon Dioxide; Spectroscopy, Fourier Transform Infrared; Surface Properties; X-Ray Diffraction

Herein we report a new strategy for protein refolding by taking advantage of the unique surface and pore characteristics of ethylene-bridged periodic mesoporous organosilica (PMO), which can effectively entrap unfolded proteins and assist refolding by controlled release into the refolding buffer. Hen egg white lysozyme was used as a model protein to demonstrate the new method of protein refolding. Through loading of denatured proteins inside uniform mesoporous channels tailored to accommodate individual protein, protein aggregation was minimized, and the folding rate was increased. Poly(ethyleneglycol) (PEG)-triggered continuous release of entrapped denatured lysozyme allowed high-yield refolding with high cumulative protein concentrations. The new method enhances the oxidative refolding of lysozyme (e.g., over 80% refolding yield at about 0.6 mg/mL).

Topics: Muramidase; Oxidation-Reduction; Polyethylene Glycols; Protein Denaturation; Protein Folding; Silanes; Silicon Dioxide