Figure 9: Schematic representing possible crosslinking reaction between decellularized scaffold and CS/nHAp composite in the presence of EDC and NHS. Nucleophilic attack by NH2 group of chitosan leads to formation of amide bond between COOH group of decellularized scaffold and NH2 group of CS/nHAp composite. EDC and NHS catalyze the covalent bindings between carboxylic acid and amino groups, thus, crosslinking CS/nHAp composite with the decellularized scaffold and forming CS/nHAp-modified decellularized scaffold. DS: decellularized scaffold, EDC: 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide, NHS: N-hydroxy succinimide.