Chemical binding

About: Chemical binding is a research topic. Over the lifetime, 1822 publications have been published within this topic receiving 52516 citations.

Study on Tissue Engineering Scaffolds of Silk Fibroin-Chitosan/ Nano-Hydroxyapatite Composite

Abstract: The porous scaffolds of silk fibroin-chitosan /nano-hydroxyapatite (SF-CS / n-HA) were fabricated through the freeze- drying technique. Component, structure and morphology of scaffolds were studied by infrared (IR), X-ray diffusion (XRD) and scanning electron microscope (SEM), and the mechanical properties of the scaffolds were measured. The simulated body fluid (SBF) experiments were conducted to assess the bioactivity of the scaffolds. Results indicate that chemical binding is formed between HA and organics, the macropore diameter of the scaffolds varies from 150 to 400μm. The porous scaffolds with interconnected pores possess a high porosity of 78%-91% and compressive strength of 0.26 -1.96MPa, which can be controlled by adjusting the concentration of organic phases and prefreezing temperature. In the SBF tests, a layer of randomly oriented bone-like apatite crystals formed on the scaffold surface, which suggested that the composite material had good bioactivity. Studies suggest the feasibility of using SF-CS /n-HA composite scaffolds for bone tissue engineering.

Mechanism of the antipeptic action of anionic carbohydrate and its clinical application for the treatment of peptic ulcer.

Abstract: The antipeptic effects of various anionic carbohydrate preparations were found to vary depending on the source and molecular weight of carbohydrate, the types and the grades of esterification, and minerals attached to anionic groups. Dextran sulfate inhibits all proteases separated from gastric mucosa. The antipeptic effects are assumed to be due to the chemical binding of anionic carbohydrate not only with pepsin, but also with substrate proteins basing on the results obtained in both in vitro and electrophoretic experiments. Immunoelectrophoretic analysis revealed that the peptic ulcer-covering ‘white coating’ contains plasma proteins. These findings are thought to indicate that anionic carbohydrate can be used for the treatment of peptic ulcer. The significance of chemical binding of anionic carbohydrate to ‘white coating’ is stressed.

Development of a solid-phase microextraction fiber by the chemical binding of graphene oxide on a silver-coated stainless-steel wire with an ionic liquid as the crosslinking agent

Abstract: Graphene oxide was bonded onto a silver-coated stainless-steel wire using an ionic liquid as the crosslinking agent by a layer-by-layer strategy. The novel solid-phase microextraction fiber was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy and Raman microscopy. A multilayer graphene oxide layer was closely coated onto the supporting substrate. The thickness of the coating was about 4 μm. Coupled with gas chromatography, the fiber was evaluated using five polycyclic aromatic hydrocarbons (fluorene, anthracene, fluoranthene, 1,2-benzophenanthrene, and benzo(a)pyrene) as model analytes in direct-immersion mode. The main conditions (extraction time, extraction temperature, ionic strength, and desorption time) were optimized by a factor-by-factor optimization. The as-established method exhibited a wide linearity range (0.5-200 μg/L) and low limits of determination (0.05-0.10 μg/L). It was applied to analyze environmental water samples of rain and river water. Three kinds of the model analytes were quantified and the recoveries of samples spiked at 10 μg/L were in the range of 92.3-120 and 93.8-115%, respectively. The obtained results indicated the fiber was efficient for solid-phase microextraction analysis.

Two-dimensional correlation analysis of Raman microspectroscopy of subcellular interactions of drugs in vitro.

Abstract: Two-dimensional (2D) correlation analysis is explored to data mine the time evolution of the characteristic Raman microspectroscopic signatures of the subcellular responses of the nucleoli of human lung cancer cells to the uptake of doxorubicin. A simulated dataset of experimental control spectra, perturbed with systematically time-dependent spectral changes, constituted by a short-term response which represents the initial binding of the drug in the nucleolus, followed by a longer term response of the organelle metabolism, is used to validate the analysis protocol. Applying 2D correlation analysis, the in phase, synchronous correlation coefficients are seen to contain contributions of both response profiles, whereas they can be independently extracted from the out of phase, asynchronous correlation coefficients. The methodology is applied to experimental data of the uptake of doxorubicin in human lung cell lines to differentiate the signatures of chemical binding and subsequent cellular response.

Enhanced Electrochemical Performance of Lithium–Sulfur Batteries with Surface Copolymerization of Cathode

Abstract: Lithium–sulfur batteries with high specific capacity, low-cost, and environmental benignity show great potential for advanced energy storage systems. However, the poor conductivity of elemental sulfur, the shuttle effect and the uncontrollable deposition of lithium sulfides species result in poor cycling stability and low Coulombic efficiency. Despite the recent success in trapping soluble polysulfides via porous matrix and chemical binding, considerable weight of cathode is occupied by the conductive additives. Herein, we discovered that copolymerization of sulfur on the surface of cathode with 1,3-diisopropenylbenzene is highly effective to bind with sulfur species. Compared with bare traditional cathode, the cathode covered with vulcanized poly(sulfur-random-1,3-diisopropenylbenzene) exhibit remarkable capacity retention (916.6 mAh g−1 after 100 cycles at 0.2C). It delivers high specific capacities at higher C-rates (up to 400 mAh g−1 at 2C). The superior electrochemical properties with high sulfur utilization ratio could be attributed to the protective effect of surface modification with poly(sulfur-random-1,3-diisopropenylbenzene).