Abstract:The aim of this research was to prepare a novel sponge-like porous hydrogel scaffold based on human-like collagen (HLC) that could be applied in cartilage tissue regeneration. In this study, bovine serum albumin (BSA) was used as a porogen to prepare the porous hydrogel, which had not been previously reported. Glutamine transaminase (TGase) was used as the cross-linker of the hydrogel, because it could catalyze the cross-linking of BSA. During the crosslinking process, BSA and HLC were mixed together, which affected the cross-linking of HLC. When the cross-linking was completed, the non-crosslinked section formed pores. The microstructure, porosity, swelling properties, and compressive properties of the hydrogel were studied. The results showed that the pore size of the hydrogel was between 100 and 300 µm, the porosity reached up to 93.43%, and the hydrogel had rapid water absorption and suitable mechanical properties. Finally, we applied the hydrogel to cartilage tissue engineering through in vitro and in vivo research. The in vitro cell experiments suggested that the hydrogel could promote the proliferation and adhesion of chondrocytes, and in vivo transplantation of the hydrogel could enhance the repair of cartilage. In general, the hydrogel is promising as a tissue engineering scaffold for cartilage.

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A variety of experimental techniques (multinuclear NMR, Raman, fluorescence polarization, small-angle neutron scattering, viscosity, turbidity, static and dynamic light scattering experiments) have been employed to investigate the nature of the sol-gel transition of tetramethoxysilicate, Si(OCH,), (TMOS). These experiments probe changes in structural and dynamical properties at the macroscopic and microscopic levels in the course of the sol-gel transition. The experimental results are compared with recent theories for the gelation process. The experiments show that no drastic change in structure occurs at the gelation threshold of TMOS. The formed silica network exhibits a self-similar structure, and the gross features of the sol-gel transition of TMOS can be described within the framework of percolation theory. The underlying growth process might be classified as reaction-limited cluster-cluster growth. However, the detailed chemical structure and reactivity of the reactants, e.g., the time-dependent functionality of the monomers during the hydrolysis step, also play an important role and have to be taken into account for a more quantitative theoretical description of this gelation process.

We reported a novel BiOI/mesoporous TiO2 photoanode for solar cells, which was fabricated with BiOI attached onto a three-dimensional mesoporous TiO2 film by a chemical bath deposition (CBD) method. BiOI was revealed as an efficient and environmental friendly semiconductor sensitizer to make TiO2 respond to visible light. Based on this photoanode, mesoporous TiO2-based solar cell sensitized by BiOI exhibited promising photovoltaic performance. Meanwhile, the optimization of photovoltaic performance was also achieved by varying cycles of deposition immersions. The highest open circuit voltage and short circuit current of the solar cell can reach 0.5 V and 1.5 mA/cm(2), respectively.