pH-Sensitive Stimulus Responsive ZIF-8 Composites Nanoparticles Coated with Folic Acid-Conjugated Chitosan for Targeted Delivery of Curcumin

Zeolitic imidazolate framework-8 (ZIF-8) is a promising material for drug delivery, but its poor stability limits its wide application. In this work, homogeneous dodecahedral ZIF-8 was prepared by the room-temperature solution stirring method, and to improve the stability of ZIF-8, ZIF-8@mSiO₂ and DZIF-8 (ZIF-8 after calcination) @PMO composites with the core-shell structure were obtained using mesoporous silica (mSiO₂) and periodic mesoporous organic silica (PMO) coatings. Folic acid-coupled chitosan (CS-FA) was modified on nanoparticles, and curcumin (CUR) was used as a model anti-tumor drug to obtain the drug delivery systems with targeting and pH stimulation response: ZIF-8@mSiO₂@CUR@CS-FA and DZIF-8@PMO@CUR@CS-FA, which exhibited good dispersion and high drug loading capability. In addition, we used the MTT assay to assess the cytotoxicity of the drug-carrying systems and selected human cervical cancer cells (Hela) as model cells. The results of the in vitro experiments suggested that the final CUR-loaded drug delivery systems had significantly increased anticancer efficiency compared with the free drug CUR, which improved the therapeutic effect of the hydrophobic CUR on tumors. In conclusion, the pH-responsive nanocarriers provided potential for the targeted delivery of anticancer medication, resulting in a platform for drug-controlled release and cancer therapy.