Figure 2.

Creating the 3D-IHI nanoscaffold using biodegradable nanomaterials. (a) A schematic diagram showing that the 3D-IHI nanoscaffold could enhance chondrogenic differentiation of BMSC through a synergy between N-cadherin and FAK-mediated pathways. (b) The strong interactions between MnO₂ NTs and functional groups commonly existing in ECM proteins effectively supported cell attachment as demonstrated via SEM image. The inset TEM image reveals the cubic hollow structure of the MnO₂ NT (the red color indicates the BMSC, while the blue color indicates the MnO₂ NTs). (c) Bicinchoninic acid assay indicates the enhanced absorption toward gelatin from MnO₂ NT compared to control groups. (d) The MnO₂ NT-templated assembly method significantly enhanced cell–matrix interaction as demonstrated through the upregulated expression patterns of the FAK gene. (e) Representative immunostaining images showing the improved chondrogenesis of BMSC in the BMSC–IHI nanoscaffold group compared to the control groups. The numbers represent the type II collagen (Col II) staining positive cells counted through imageJ. Scale bar: 50 μm. (f)–(h) The expression of chondrogenic genes, including SOX9 (f), Aggrecan (g) and Col II (h), were characterized via qRT-PCR measurement. All data are presented as mean ± SD (n = 4). ^*P < 0.05, ^**P < 0.01, ^***P < 0.001.