An organic-inorganic hybrid scaffold with honeycomb-like structures enabled by one-step self-assembly-driven electrospinning.

Electrospun organic/inorganic hybrid scaffolds have been appealing in tissue regeneration owing to the integrated physicochemical and biological performances. However, the conventional electrospun scaffolds with non-woven structures usually failed to enable deep cell infiltration due to the densely stacked layers among the fibers. Herein, through self-assembly-driven electrospinning, a polyhydroxybutyrate/poly(ε-caprolactone)/58S sol-gel bioactive glass (PHB/PCL/58S) hybrid scaffold with honeycomb-like structures was prepared by manipulating the solution composition and concentration during a one-step electrospinning process. The mechanisms enabling the formation of self-assembled honeycomb-like structures were investigated through comparative studies using Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) between PHB/PCL/58S and PHB/PCL/sol-gel silica systems. The obtained honeycomb-like structure was built up from nanofibers with an average diameter of 370 nm and showed a bimodal distribution of pores: large polygonal pores up to hundreds of micrometers within the honeycomb-cells and irregular pores among the nanofibers ranging around few micrometers. The cell-materials interactions were further studied by culturing MG-63 osteoblast-like cells for 7 days. Cell viability, cell morphology and cell infiltration were comparatively investigated as well. While cells merely proliferated on the surface of non-woven structures, MG-63 cells showed extensive proliferation and deep infiltration up to 100-200 μm into the honeycomb-like structure. Moreover, the cellular spatial organization was readily regulated by the honeycomb-like pattern as well. Overall, the newly obtained hybrid scaffold may integrate the enhanced osteogenicity originating from the bioactive components, and the improved cell-material interactions brought by the honeycomb-like structure, making the new scaffold a promising candidate for tissue regeneration.