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Poly(vinyl alcohol)(PVA)/hydroxylapatite(HA) hybrid hydrogels used for bioactive artificial cartilage were prepared by compounding in situ with sol-gel synthesis of HA in PVA solution. To draw comparisons, both physical mixing and deposition in situ methods were also used to prepare hybrid hydrogels. The influence of contents and dispersed condition of HA in PVA matrixes on hydrogel's mechanical strength were investigated and compared. The micromorphology and crystalline structure of HA were also observed by some analysis techniques. It was verified that the distinct conglomeration of HA particles in PVA matrixes were overcome using sol-gel in situ methods, and mechanical strength of PVA/HA hydrogels increased obviously compared to deposition in situ and physical mixing methods. HA particles being dispersed uniformly in PVA hydrogels prepared by sol-gel in situ compounding were of crystalline structure, which acted as a kind of heterogeneous nucleating agent improving the crystallization of PVA by depressing the dependence of the crystalline process on the temperature and external factors. hence raising the tensile strength of hybrid hydrogels. [ABSTRACT FROM AUTHOR]

Bacterial infection and inferior osseointegration are major complications associated with titanium (Ti) based implants. Although surface-engineered zinc oxide (ZnO) nanorods exhibit remarkable antibacterial ability, their potential biomedical applications are hampered by their pronounced cytotoxicity. Herein, inspired by the in vivo degradation process of znic, ZnO nanorods are converted into thermodynamically more stable zinc phosphate (Zn3(PO4)2 )through a simple hydrothermal treatment in a hydrogen phosphate solution. By adjusting the conversion ratio, the surface morphology, release of zinc ions (Zn2+), and generation of reactive oxygen species can be finely tailored to overcome the cytotoxicity of ZnO nanorods while preserving their antibacterial capability. Furthermore, an optimized amount of Zn2+ released from the ZnO/Zn3(PO4)2 hybrid coating enhances osteogenic differentiation and extracellular matrix mineralization of human bone marrow mesenchymal stem cells by reprogramming their metabolic configuration. An implant-related infection model in rabbit femurs indicates that the hybrid ZnO/Zn3(PO4)2 coating can even promote osseointegration in the presence of pathogenic bacteria. This surface modification strategy which endows Ti-based implants with superior anti-bacterial and pro-osteogenic properties holds great clinical potential for orthopedic and dental applications. [ABSTRACT FROM AUTHOR]

The in vitro degradation and cytotoxicity of bacterial cellulose (BC) and its degradation products were studied for potential applications in bone tissue engineering. Emission scanning electron microscope was used to observe the morphology of original materials and their degradation products. The degradation was evaluated by measuring the concentration of reducing sugar by using ultraviolet spectrophotometer. Bone forming osteoblast (OB) cells and infinite culture cell line L929 fibroblasts were used to measure the cytotoxicity of materials using the MTT assay. Both types of cells proliferated normally with the BC and its degradation products with a cytotoxicity graded of 0-1. Nevertheless, the bone-forming target OB cells were more susceptible to cytotoxicity than the infinite culture fibroblast cells L929 fibroblasts. The results indicate that the BC is not very cytotoxic and that tissue functional cells are more suitable for evaluating the cytotoxicity of biomedical materials. [ABSTRACT FROM AUTHOR]

In this paper, we report a novel organic monomer containing dual photocross-linkable groups and success in realizing photoinduced homeotropic alignment of nematic liquid crystals (LCs) with it. It was first revealed that direct irradiation of the photoalignment thin film with nonpolarized ultraviolet (UV) light at 365.0 nm brought out homeotropic orientation of the photopolymer as a result of the photocross-linking of the dual photoreactive groups. When the thin film was obliquely irradiated with nonpolarized UV light, the pretilt angles of nematic LC were generated. Interestingly, we find that the hydrophobicity of the photopolymer increases with increasing irradiation time. In discussing the mechanism of the homeotropic alignment, it was found that the incorporation of the dual photofunctional group of the photoalignment molecules as well as the extreme hydrophobicity of the photopolymer play the essential roles. This monomer cross-linked film is expected as a promising homeotropic alignment film with rubbing-free processing for the fabrication of advanced vertical alignment LC displays. [ABSTRACT FROM AUTHOR]

The reactive thermal-sensitive hydrogels, which combined the reversible thermosensitive and mild reactive property, were designed based on thiol-ene reaction in physiological conditions between thiol and acrylate capped thermosensitive Poloxamer 188. The modified P188A, P188SH, and their reactivity were characterized by 1H NMR, FT-IR, GPC, DSC, Ellman method, and Rheometer. It was found that the thiol-ene reaction was pH and thermal-sensitive. There was 77.7% SH involved into the reaction at 37.0 °C and pH 7.4 within the first 30 min. The most of molecules reacted as CC/SH mol ratio was 1.5. The exothermic thiol-ene reaction was mild, with about Δ H= −91.18 J/g changes. The multiblocks or network structure limited the dissolution of hydrogel, correspondingly the gel’s duration and the release time of methylene blue were prolonged to 124 h. The experimental results indicated the reactive thermal-sensitive hydrogel’s potential applications in drug delivery, tissue engineering, and cell encapsulation. [ABSTRACT FROM AUTHOR]

Titanium (Ti) with nanoscale structure on the surface exhibits excellent biocompatibility and bone integration. Once implanted, the surgical implantation may lead to bacterial infection and inflammatory reaction, which cause the implant failure. In this work, irregular and nanorod-shaped ZnO nanoparticles were doped into TiO2 nanotubes (TNTs) with inner diameter of about 50 nm by electro-deposition. The antibacterial properties of ZnO incorporated into TiO2 nanotubes (TNTs/ZnO) were evaluated using Staphylococcus aureus (S. aureus). Zn ions released from the nanoparticles and the morphology could work together, improving antibacterial effectiveness up to 99.3% compared with the TNTs. Macrophages were cultured on the samples to determine their respective anti-inflammatory properties. The proliferation and viability of macrophages were evaluated by the CCK-8 method and Live&Dead stain, and the morphology of the cells was observed by scanning electron microscopy. Results indicated that TNTs/ZnO has a significant inhibitory effect on the proliferation and adhesion of macrophages, which could be used to prevent chronic inflammation and control the inflammatory reaction. Besides, the release of Zn ions from the ZnO nanoparticles is a long-term process, which could be beneficial for bone integration. Results demonstrate that ZnO deposited into TNTs improved the antibacterial effectiveness and weakened the inflammatory reaction of titanium-based implants, which is a promising approach to enhance their bioactivity. [ABSTRACT FROM AUTHOR]