Figure 2. Physicochemical characterization and drug release of manipulated nanoparticles. A) The FTIR spectrum of free chitosan nanoparticles and B) Chitosan nanoparticles conjugated with rh-EGF protein. The 1635.69 cm-1 spectrum shows the non-covalent bonds between carboxyl groups of the protein and amino groups of chitosan, which indicates the difference between two groups of nanoparticles, showing the connection between chitosan and rh-EGF in CS-EGF nanoparticles. C) CS-EGF NPs drug release profile, measured at 0, 4, 8, 16, 24, and 30h of the experiment and T=37±1 ◦C, pH 7.4.