Hailin Zhu

Preparation and antibacterial property of silver-containing mesoporous 58S bioactive glass.

The modified mesoporous 58S bioglass (SM58S) was prepared through surface modification of the mesoporous 58S bioglass (M58S) with γ-aminopropyl triethoxysilane (KH550). The results of Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) showed that the amino groups were grafted to the surface of M58S after modification with KH550. The silver-containing SM58S (Ag-SM58S) and M58S (Ag-M58S) were prepared by the dipping method. The Ag(+) loading capacity, release rate and antibacterial properties of Ag-SM58S and Ag-M58S were investigated. It is indicated that surface modification of M58S with KH550 can improve the Ag(+) loading capacity. The result of antibacterial property showed that Ag-SM58S exhibited significant anti-bacterial effects against Escherichia coli and Staphylococcus aureus. The sustained release of Ag(+) from Ag-SM58S for 768h ensured excellent antibacterial property of Ag-SM58S. In vitro osteoblast proliferation and differentiation tests showed that Ag-SM58S was a good matrix for the growth of osteoblasts. Consequently, the results of the study suggested that Ag-SM58S might be a promising bone repair material.

Structural Characteristics and Properties of Silk Fibroin/Poly(lactic acid) Blend Films

This paper describes the preparation and characterization of blend films composed of regenerated silk fibroin (SF) and poly(lactic acid) (PLA). FT-IR and XRD of the SF/PLA blend films with different ratios indicated that the secondary structural transition of SF from Silk I to Silk II was induced upon blending with PLA. The effects of SF/PLA blend ratios on the mechanical and physical properties of the blend films were investigated. Compared to pure SF film, the mechanical and thermal properties of the blend films were improved, and surface hydrophilicity and swelling capacity decreased due to the secondary structural transition of SF to Silk II. Among the blend films with different ratios, the SF/PLA blend film with 7 wt% PLA content showed excellent mechanical properties. Meanwhile, the BSA adsorption amount on the blend film increased with the increase of PLA content. In vitro cell adhesion test showed that the blend film was a good matrix for the growth of L929 mouse fibroblast cells. Consequently, controlling the PLA content in the SF film can improve the mechanical and physical properties of the SF film and provide a promising opportunity to widen potential application of SF in the biomaterials field.

Preparation and characterization of bioactive mesoporous calcium silicate–silk fibroin composite films

Composite films of bioactive mesoporous calcium silicate (MCS)/silk fibroin (SF) and conventional calcium silicate (CS)/SF were fabricated by the solvent casting method, and the structures and properties of the composite films were characterized. Results of field emission scanning electron microscope (FESEM) indicated that MCS or CS was uniformly dispersed in the SF films. The measurements of the water contact angles suggested that the incorporation of either MCS or CS into SF could improve the hydrophilicity of the composite films, and the former was more effective than the later. The bioactivity of the composite films was evaluated by soaking in a simulated body fluid (SBF), and the formation of a hydroxycarbonate apatite (HCA) layer was determined by XRD and FT-IR. The results showed that the MCS/SF composite films have significantly enhanced apatite-forming bioactivity compared with the CS/SF composite films owing to the highly specific surface area and pore volume of MCS. In vitro cell attachment and proliferation tests showed that the MCS/SF composite film was a good matrix for the growth of MG63 cells. Consequently, the MCS/SF composite film possessed excellent physicochemical and biological properties, indicating its potential application for bone tissue engineering by designing 3D scaffolds according to its corresponding composition.

Propeller-shaped ZnO nanostructures obtained by chemical vapor deposition: photoluminescence and photocatalytic properties

Propeller-shaped and flower-shaped ZnO nanostructures on Si substrates were prepared by a one-step chemical vapor deposition technique. The propeller-shaped ZnO nanostructure consists of a set of axial nanorod (50 nm in tip, 80 nm in root and 1 µm in length), surrounded by radial-oriented nanoribbons (20-30nm in thickness and 1.5 µm in length). The morphology of flower-shaped ZnO nanostructure is similar to that of propeller-shaped ZnO, except the shape of leaves. These nanorods leaves (30nm in diameter and 1-1.5 µm in length) are aligned in a radial way and pointed toward a common center. The flower-shaped ZnO nanostructures show sharper and stronger UV emission at 378nm than the propeller-shaped ZnO, indicating a better crystal quality and fewer structural defects in flower-shaped ZnO. In comparison with flower-shaped ZnO nanostructures, the propeller-shaped ZnO nanostructures exhibited a higher photocatalytic property for the photocatalytic degradation of Rhodamine B under UV-light illumination.

Preparation and hemostatic property of low molecular weight silk fibroin

Abstract Effective hemorrhage control becomes increasingly significant in today’s military and civilian trauma, while the topical hemostats currently available in market still have various disadvantages. In this study, three low molecular weight silk fibroins (LMSF) were prepared through hydrolysis of silk fibroin in a ternary solvent system of CaCl2/H2O/EtOH solution at different hydrolysis temperatures. Fourier transform infrared spectroscopy analysis showed that the content of β sheet structure in the LMSF decreased with the increase in hydrolysis temperature. The results of thromboelastographic and activated partial thromboplastin time methods showed that the LMSF hydrolyzed at 50 °C can significantly strengthen the coagulation in blood and activate the intrinsic pathway of coagulation cascade. In the murine hepatic injury model, the LMSF hydrolyzed at 50 °C can promote the blood clotting and decrease the blood loss and bleeding time. Based on these results, it can be suggested that the developed LMSF has the excellent hemostatic effect and may be a promising material in clinical hemostatic application.

Effect of the degree of hydrolysis and polymerisation on the melting process of thermoplastic poly(vinyl alcohol)

ABSTRACT In this work, the thermoplastic poly(vinyl alcohol) (TPVA) blend films were efficiently prepared using pure poly(vinyl alcohol) (PVA) and caprolactam–MgCl2 ·6H2O via the aqueous method on the condition of achieving the melting process of PVA. The effect of the degree of polymerisation (DP) and hydrolysis (DH) of PVA on plasticisation was studied using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction, differential scanning calorimeter, and thermo gravimetric analysis. The plasticising effect increases initially and then decreases with the increase of DP owing to the destruction of hydrogen bonding and the decrease in regularity in PVA. The plasticising effect increases with the increase in DH, because the plasticiser weakens the hydrogen bonding of intro-intra molecular in PVA, which is confirmed by the shift of the –OH characteristic peak of FT-IR spectra. The thermal processing windows increase owing to the coordination effect between hydrogen bonding and crystallinity. TPVA-1799 had the largest thermal processing window (120°C) and the molten filament was extruded, which were both significant for melt spinning. GRAPHICAL ABSTRACT

Synthesis of 2H-Chromenones from Salicylaldehydes and Arylacetonitriles

An efficient and convenient protocol for the synthesis of 2H-chromenones has been developed. In the presence of tBuOK in DMF, good to excellent yields of various chromenones were obtained from the corresponding salicylaldehydes and arylacetonitriles. No protection of inert gas atmosphere is required here.