**Acknowledgements**

facilitate the production of core-sheath structure via the electrospinning process. The coresheath structure lessens the possibility of the exposure of Fol-8Col to the harsh organic solvents and thus protects Fol-8Col from activity loss. We assumed that the collagen derivate sequences, RGD sequences, and the triple-helix have been preserved in Fol-8Col, which is an essential

We have successfully prepared three different nanofibrous scaffolds *via* co-electrospinning,

Regenerated silk fibroin/TMOS hybrid nanofibers showed superior fibroblast attachment, compared to pure silk fibroin nanofibers, due to relatively higher hydrophilicity. Accordingly, the silk/TMOS nanofibrous composites showed a sharp decrease in water contact angle than pure regenerated silk fibroin nanofiber due to the spatial net structure formed *via* Si–O–Si– connection which was responsible for water capacity. Interestingly, the electrospinning process caused adjacent fibers to 'weld' at contact points, as confirmed by SEM analysis. This study of simple incorporation silk with TMOS has merit of preserving the excellent biocom‐ patibility of silk, and the fibrous three-dimensional silk/TMOS scaffold can support signifi‐ cantly enhanced L929 adhesion than pure silk. Thus this method might open a new pathway to preparing various functional scaffolds with enhanced bioactivity for in vitro tissue engi‐

Nano hydroxyapatite was successfully deposited on regenerated silk fibroin nanofibrous scaffolds by a biomimetic Ca–P method. It was found that the primary nHA crystals with a diameter about 30 nm were well-distributed on the surface of the nanofibrous substrates. The ALP expression of the cells was improved on mineralized silk/nHA nanofibers during the cell culture periods, irrespective of the cell number which was leveling off (3 to 7 days). It appeared that the nHA presenting in mineralized silk/nHA nanofibers had a greater improvement on differentiation stages than in an early stage of cultivation, such as adhesion and proliferation. The cell cultivation in this study demonstrated that silk/nHA nanocomposite scaffold could support the early stage of osteoblast adhesion and had a significant effect on the differentiation stage, suggesting that this composite scaffold may be a promising biomaterial for bone tissue

Furthermore, Fol-8Col, an original designed recombinant collagen-like protein, has been successfully encapsulated in PLGA in the form of core-sheath fibrous structure via emulsion electrospinning. The homogenous encapsulation of the Fol-8Col in a core-sheath form was characterized by the fluorescence micrographs of NHS-Fluorescein labeled Fol-8Col/PLGA and transmission electron microscope. The cytocompatibility of Fol-8Col/PLGA fibers proved its superior ability for L929 cells adhesion compared to that of the neat PLGA. In this regard, this emulsion electrospinning process might open a new pathway to preparing tailored coresheath fibers to ultimately fulfill the functions of drug release device as well as tissue engi‐

post-treatment processes and emulsion electrospinning.

element of its bioactivity.

**5. Conclusions**

120 Advances in Nanofibers

neering application.

engineering.

neering scaffold.

The authors acknowledge the support of Shinshu University Global COE Program "Interna‐ tional Center of Excellence on Fiber Engineering".
