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Controllable regulation of stem cell differentiation is a critical concern in stem cell-based regenerative medicine. In particular, there are still great challenges in controlling the directional differentiation of neural stem cells (NSCs) into neurons. Herein, we developed a novel linear-branched poly(β-amino esters) (S4-TMPTA-BDA-DT, STBD) through a two-step reaction. The synthesized linear-branched polymers possess multiple positively charged amine terminus and degradable intermolecular ester bonds, thus endowing them with excellent properties such as high gene load, efficient gene delivery, and effective gene release and transcription in cells. In the mCherry transfection test, a high transfection efficiency of approximately 70% was achieved in primary NSCs after a single transfection. Moreover, STBD also showed high biocompatibility to NSCs without disturbing their viability and neural differentiation. With the high gene delivery property, STBD is capable of delivering siRNA (shSOX9) expression plasmid into NSCs to significantly interfere with the expression of SOX9, thus enhancing the neuronal differentiation and maturation of NSCs. The STBD/DNA nano-polyplex represents a powerful non-viral approach of gene delivery for manipulating the differentiation of stem cells, showing broad application prospects in NSC-based regenerative therapy for treating neurodegenerative diseases.

TiB2-SiC-Si ceramic composites were fabricated based on molten silicon infiltration method. The influence of particle size distribution of TiB2 on the microstructure and mechanical properties of TiB2-SiC-Si ceramic composites was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron universal testing machines, etc. The results showed that the composite consisted of TiB2, SiC and Si phases. The microstructure analysis showed that: the content of residual Si could be controlled less than 16 vol.% in the composite by particle size distribution. When the particle size distribution of TiB2 was 42:32:26, the TiB2-SiC-Si composite showed the optimum properties. The open porosity, volume density, Vickers-hardness, flexural strength and fracture toughness were 0.51%, 3.63 g/cm3, 17 GPa, 275 MPa and 5.7 MPa·m1/2, respectively.