Construction of the targeted and pH-sensitive paclitaxel drug delivery system RGD/PTX@ZIF-90 and anti-tumor activity research

Abstract

Tumors area common cause of morbidity and mortality. High treatment efficiency and low drug toxicity are key for effective tumor treatment. Here, the pH-sensitive material ZIF-90 was synthesized by the liquid-phase diffusion method for loading paclitaxel (PTX), and the targeting peptide (RGD) was prepared by the solid-phase synthesis method to modify it (RGD/PTX@ZIF-90). The skeleton of RGD/PTX@ZIF-90 collapses in the acidic tumor microenvironment, thereby releasing PTX and mediating the controlled release of the drug. ZIF-90 below 300 nm was obtained by adjusting the ratio of metal ions and organic ligands in the characterization experiment. In addition, in vitro drug release experiments showed that the drug release rate was greater at pH = 5.5 than at pH = 7.4. The lethal rate of RGD/PTX@ZIF-90 to human breast cancer cells (MCF-7) was 44.5%, which was higher than the lethal rate of PTX alone (37.3%) in the cytotoxicity experiment and apoptosis experiment. Uptake experiments revealed that RGD/PTX@ZIF-90 mainly existed in the cytoplasm of MCF-7, which suggests that the drug had successfully entered the cell to achieve the therapeutic effect. The loading of the nano-medicine carrier ZIF-90 and the modification of the targeting peptide RGD significantly improve the therapeutic effect of PTX and indicate that this system could be used to treat breast cancer.