Reinforced cell-derived matrix-silk fibroin scaffolds for bone tissue engineering

A successful bone-tissue engineering strategy requires appropriate materials design. Recently, materials design has been focused on mimicking native bone tissue (1). The present work's main objective was to create an enhanced scaffold that represented the composition and structure of bone tissue. In this reasoning, scaffolds were prepared by mixing silk fibroin with cell-derived matrices and reinforced with carbon nanotubes (2, 3). The structure and mechanical properties of developed scaffolds were evaluated structurally, mechanically, and biologically. The results showed that the developed scaffolds were elastic, with stiffness of ≈ 5 kPa, pore sizes of ≈ 112 ± 22 µm, and total porosity of ≈ 75 ± 3%. Also, the scaffolds showed to be bioactive in vitro. The biological assessment in vitro revealed that human adipose-derived stem cells (hASCs) could adhere, spread and proliferate on top of the scaffolds. Interestingly, cells could differentiate into osteoblasts without supplemented media, as demonstrated by the collagen deposition, incremented ALP activity, and expression of osteogenic-related genes (e.g., Runx-2, Col Iα, ALP, and OPN). Ultimately, the present scaffolds demonstrated no harmful effect on the hemocompatibility assay, foreseeing no detrimental impact on future in vivo tests.

These results confirmed that the carbon nanotubes-reinforced cell-derived matrix-silk fibroin scaffolds are promising bone tissue engineering tools.