Several studies have shown that nanosilicate-reinforced
scaffolds
are suitable for bone regeneration. However, hydrogels are inherently
too soft for load-bearing bone defects of critical sizes, and hard
scaffolds typically do not provide a suitable three-dimensional (3D)
microenvironment for cells to thrive, grow, and differentiate naturally.
In this study, we bypass these long-standing challenges by fabricating
a cell-free multi-level implant consisting of a porous and hard bone-like
framework capable of providing load-bearing support and a softer native-like
phase that has been reinforced with nanosilicates. The system was
tested with rat bone marrow mesenchymal stem cells in vitro and as
a cell-free system in a critical-sized rat bone defect. Overall, our
combinatorial and multi-level implant design displayed remarkable
osteoconductivity in vitro without differentiation factors, expressing
significant levels of osteogenic markers compared to unmodified groups.
Moreover, after 8 weeks of implantation, histological and immunohistochemical
assays indicated that the cell-free scaffolds enhanced bone repair
up to approximately 84% following a near-complete defect healing.
Overall, our results suggest that the proposed nanosilicate bioceramic
implant could herald a new age in the field of orthopedics.