Fabrication of Ion-Crosslinking Aminochitosan Nanoparticles for Encapsulation and Slow Release of Curcumin

Curcumin (Cur) has anticancer activities but has poor stability, which can be improved using carrier materials. In this study, chitosan was aminated to increase the number of amino groups on its surface, modified with folic acid (FA), and then made into nanoparticles by ionic crosslinking. Owing to ion interaction, the negatively charged, non-toxic tripolyphosphate (TPP) interacted with the positively charged amino group on the aminated chitosan (AmCS) surface, producing FA-AmCS-TPP nanoparticles, which were then characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrophotometry (FT-IR), and thermogravimetric analysis (TGA). Their small particle size (175.2 ± 0.99 nm) and good surface positive potential (+42.4 mV) are beneficial for carrying antitumor drugs. We subsequently investigated whether coating of Cur by AmCS allows slow drug release by FA-AmCS-TPP nanoparticles in different pH environments, and estimated the Cur loading efficiency (EE-Cur). Our results showed that the cumulative release rate of Cur at 48 h was 56.2%, and that the EE-Cur reached 94.26 ± 0.91% with nanoparticles composed of 0.10 g AmCS, 10.0 mg FA, 10.0 mg TPP, and 15.0 mg Cur. Additionally, cytotoxicity experiments showed that the Cur/FA-AmCS-TPP nanoparticles had good targeting ability for tumor cells. Therefore, the non-toxic targeted composite nanoparticles had potential as a new antitumor agent that can overcome the limitations of Cur.