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The porous scaffold of hydroxyapatite (HA) is highly promising for application in clinics owing to its interconnected porous structure, excellent mechanical properties, biocompatibility, and biological activity; however, the effectiveness of its antibacterial properties and osteoinductivity limits its wide usage. In the present study, strontium (Sr), zinc (Zn), and Sr/Zn-codoped porous scaffolds of HA were prepared by an ion-exchange method and a foaming method. The results based on the density functional theory (DFT) and experimental methods suggested that Sr and Zn were successfully doped into the HA lattice structure, thereby changing the lattice parameters of HA. Sr-doped, Zn-doped, and codoped porous HA scaffolds promoted the proliferation of bone marrow stromal cells (BMSCs), and Sr-doped and codoped porous HA scaffolds promoted BMSC differentiation. In addition, Zn-doped and codoped porous HA scaffolds exhibited excellent antibacterial properties. In short, the codoped HA porous scaffolds, prepared using the simple, facile, and mild ion-exchange, and foaming methods, had good biocompatibility, osteoinductivity, and antibacterial properties, which could effectively inhibit microbial infection and promote bone tissue regeneration in the process of bone repair. Moreover, they are hopeful to be good bone replacement material in clinical application.

To improve the dielectric performance of high-dielectric-constant conductive filler/polymer composites, polyaniline was deposited on exfoliated graphite nanoplates (xGNPs) by in-situ polymerization method to form polyaniline (PANI) coated xGNPs (xGNPs@PANI) as the conductive filler for the oxidized styrene-butadienestyrene copolymer (SBS-FH) containing both hydroxyl and formyloxy groups. The results of TEM, SEM, FTIR, TGA, Raman spectrum, XPS, and WAXD showed that PANI had been coated onto the surface of xGNPs successfully. The xGNPs@PANI/SBS-FH composites were prepared by a simple solution-blending method and the homogenous distribution of xGNPs@PANI in the SBS-FH matrix was confirmed by SEM. The presence of xGNPs@PANI was found to significantly improve the dielectric properties of resultant composite compared to the unmodified xGNPs. For example, the xGNPs@PANI/SBS-FH composite near percolation threshold filled with 9.38 vol.% xGNPs@PANI showed a dielectric constant of 56.8 and a dielectric loss factor of 0.51 at 1000 Hz, while the corresponding values of xGNPs (1.19 vol.%)/SBS composite were 15.96 and 2.91 at 1000 Hz, respectively. In addition, the incorporation of xGNPs@PANI into SBS-FH could effectively enhance the thermal conductivity of resultant xGNPs@PANI/SBS-FH composite.