2.1. Materials

Dulbecco's phosphate‐buffered saline (DPBS), minimum essential medium‐α modification (α‐MEM), Dulbecco's modified Eagle's medium/nutrient mixture F‐12 (DMEM/F12), fetal bovine serum (FBS), antibiotic antimycotic solution (A/B), l‐glutamine, β‐glycerophosphate (β‐GP), ascorbic acid, glutaraldehyde, hexamethyldisilazane (HMDS), and bovine Achilles tendon collagen were purchased from Sigma‐Aldrich. Insulin–transferrin–selenium (ITS) premix was purchased from Corning. Resazurin assay was purchased from Biolegend. LIVE/DEAD Cell Imaging Kit, Vybrant DiO Cell‐Labeling Solution (DiO), and Vybrant DiD Cell‐Labeling Solution (DiD) were purchased from Invitrogen.