Figure 4.

[A] Systematic literature search (Pubmed: cartilage scaffold drug delivery) revealed trends in growth factor release for promoting chondrogenesis (query window: Sep 2013-Sep 2018). [B] Characteristic drug release profiles of factors encapsulated or soak-loaded in hydrogels/scaffolds (red) or within particles/more elaborate systems (green). Values replotted from literature sources [36,37,159,163,169–173]. [C] Depiction of chondral and osseous scaffolds for spatiotemporal control, combined into biphasic and gradient scaffolds. [D] Mechanisms to improve cartilage repair by increased chondrocyte migration from adjacent cartilage, increased MSC recruitment from the subchondral bone, and improved integration between the scaffold and surrounding tissue.