4.1 Chemical structure of bioink
As shown in Figure 2 , the main absorption bands were stretching
vibrations of C=O at 1652 cm−1 and O-H at 3480
cm−1, which was a broad and redshift due to the
formation of H-bond (Figure 2a). After printing, the redshift tendency
of kc-sa and kc-SA-C was reduced, indicating that a part of the hydrogen
bonds was destroyed during printing (Figure 2b).