Three-dimensional gas-foamed scaffolds decorated with metal phenolic networks for cartilage regeneration

Inflammation is a major impediment to the healing of cartilage injuries, yet bioactive scaffolds suitable for cartilage repair in inflammatory environments are extremely rare. Herein, we utilized electrospinning to fabricate a two-dimensional nanofiber scaffold (2DS), which was then subjected to gas foaming to obtain a three-dimensional scaffold (3DS). 3DS was modified with metal phenolic networks (MPNs) composed of epigallocatechin gallate (EGCG) and strontium ions (Sr²⁺) to afford a MPNs-modified 3D scaffold (3DS-E). Gas-foamed scaffold exhibited multilayered structure conducive to cellular infiltration and proliferation. Compared to other groups, 3DS-E better preserved chondrocytes under interleukin (IL)-1β induced inflammatory environment, showing less apoptosis of chondrocytes and higher expression of cartilage matrix. Additionally, 3DS-E facilitated the regeneration of more mature cartilage in vivo, reduced cell apoptosis, and decreased the expression of pro-inflammatory cytokines. Taken together, 3DS-E may offer an ideal candidate for cartilage regeneration.