Figure 5.

Chemical functionality of molecular necklace directs differentiation of stem cells in 3D hydrogels. Stem cells encapsulated in hydrogels with α-CD nanobeads functionalized with polar, hydrophobic, or charged chemical groups were cultured for 3 weeks to evaluate differentiation. a, α-CD (1%, w/v) with hydroxyl groups stimulated chondrogenesis of MSCs compared to control PEG hydrogels with increased early expression of Sox9 transcription factor and (matrix molecules or ECM proteins) aggrecan and type II collagen. Increased cartilage matrix production is visible by safranin-O histological staining. b, The chemical structure of hydrophobic α-CD-CH₃ was confirmed by MALDI-TOF spectrometry. Human adipose-derived stem cells (hADSCs) encapsulated in the α-CD-CH₃/PEG hydrogels increased expression of adipose-related genes several-fold. Genes include fatty acid-binding protein (FABP), lipoprotein lipase (LPL) and CEBPA (also see Supplementary Figure S2b) and produced more lipid droplets visualized by Oil red O staining, compared to control α-CD hydrogels. c, Cells cultured in hydrogels with α-CD-PO₄⁻ functionalized nanobeads (the chemical structure confirmed by MALDI-TOF) produced more mRNA for osteogenic genes COL X, OCN, and OPN compared to control hydrogels (also see Supplementary Figure S2e). Morphologically, mineralization characterized by alizarin red staining also increased in α-CD-PO₄⁻/PEG hydrogels compared to controls.