Immobilization of silk fibroin on the surface of PCL nanofibrous scaffolds for tissue engineering applications

Poly(-caprolactone) (PCL) is explored in tissue engineering (TE) applications due to its biocompatibility, processability, and appropriate mechanical properties. However, its hydrophobic nature and lack of functional groups in its structure are major drawbacks of PCL-based scaffolds limiting appropriate cell adhesion and proliferation. In this study, silk fibroin (SF) was immobilized on the surface of electrospun PCL nanofibers via covalent bonds in order to improve their hydrophilicity. To this end, the surface of PCL nanofibers was activated by ultraviolet (UV)-ozone irradiation followed by carboxylic functional groups immobilization on their surface by their immersion in acrylic acid under UV radiation and final immersion in SF solution. Furthermore, morphological, mechanical, contact angle, and Attenuated total reflection- Fourier transform infrared (ATR-FTIR) were measured to assess the properties of the surface-modified PCL nanofibers grafted with SF. ATR-FTIR results confirmed the presence of SF on the surface of PCL nanofibers. Moreover, contact angle measurements of the PCL nanofibers grafted with SF showed the contact angle of zero indicating high hydrophilicity of modified nanofibers. In vitro cell culture studies using NIH 3T3 mouse fibroblasts confirmed enhanced cytocompatibility, cell adhesion, and proliferation of the SF-treated PCL nanofibers. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46684.