Microtia,
frequently encountered in plastic surgery practice, is
usually corrected by auricular reconstruction with prostheses or autologous
cartilages. In recent decades, however, cartilage tissue engineering
has been emerging as a promising alternative for its minimal invasion
and low immunogenicity. As a critical factor for tissue engineering,
scaffolds are expected to be sufficiently porous and stiff to facilitate
chondrogenesis. In this work, we introduce novel poly-l-lactic
acid (PLLA) porous microsphere-reinforced silk-based hybrid (SBH)
scaffolds with a multihierarchical porous structure. The scaffolds
are fabricated by embedding PLLA porous microspheres (PMs) into a
blending matrix of silk fibroin (SF) and gelatin solution, followed
by mixing with a degummed silk fiber mesh and freeze-drying process.
Through adjusting the amount of PLLA PMs, the mechanical strength
approximates to natural cartilage and also balanced physical properties
were realized. Biological evaluations of SBH scaffolds, both in vitro
and in vivo, were conducted and PM-free plain silk-based (PSB) scaffolds
were applied as control. Overall, it suggests that the incorporation
of PLLA PMs remarkably improves mechanical properties and the capability
to promote chondrogenesis of SBH scaffolds, and that SBH scaffolds
appear to be a promising construct for potential applications in auricular
cartilage tissue engineering and relevant fields.