Fig. 2.

Preparation and characterization of cell cross-linked hydrogels (CxGels). a Photographs of reaction mixtures of azide-modified C2C12 cells (0.5 × 10⁶, 1.0 × 10⁶, and 2.0 × 10⁶ cells) and bAlg-DBCO solutions (1% and 2%, w/v) at 0 h and 24 h after the reaction. Photographs of dispersions of C2C12 cells (0.5 × 10⁶, 1.0 × 10⁶, and 2.0 × 10⁶ cells) and bAlg-DBCO solutions (1% and 2%, w/v) after 24 h. b (upper) Gelation kinetics determined through oscillatory time sweep of CxGels prepared from bAlg-DBCO (2%) and azide-modified C2C12 (0.5 × 10⁶, 1.0 × 10⁶, and 2.0 × 10⁶) at 37 °C under constant strain (5%) and frequency (10 rad/s). The crossover time point of the storage modulus (G′) and the loss modulus (G″) curves is defined as the mechanical gel point. (lower) Frequency sweep of CxGels prepared from bAlg-DBCO (2%) and azide-modified C2C12 (0.5 × 10⁶, 1.0 × 10⁶, and 2.0 × 10⁶) at 2 h after the start of the cross-link reactions at 37 °C under constant strain (5%). c Photographs of CxGels prepared through click reaction between azide-modified C2C12 cells (2.0 × 10⁶ cells) and bAlg-DBCO solution (2%). Scale bar indicates 5 mm. d Photographs of the word FIRST written in CxGel made through click reaction between azide-modified C2C12 cells (2.0 × 10⁶ cells) and bAlg-DBCO solution (2%). CxGels were stained with Fast Green FCF to aid visualization. Scale bar indicates 10 mm. e CLSM images of CxGels made through click reaction between azide-modified C2C12 cells (2.0 × 10⁶ cells) and bAlg-DBCO solution (2%). Green: FITC-bAlg-DBCO, red: azide-modified C2C12 cells stained with CytoTell Red. Scale bars indicate 20 μm