Lycium barbarum polysaccharides grafted with doxorubicin: An efficient pH-responsive anticancer drug delivery system.

Lycium barbarum polysaccharide-doxorubicin (LBP-DOX) nanoparticles were synthesized via a one-step Schiff base reaction between oxidized Lycium barbarum polysaccharide (oxidized LBP) and doxorubicin (DOX). The structure of LBP-DOX nanoparticles was characterized by multi-spectral methods, 1H nuclear magnetic resonance (1H NMR), transmission electron microscopy (TEM), and thermo gravimetric analysis (TGA). The rheological properties of LBP-DOX nanoparticles were studied. With the increase of shear rate, the viscosity of LBP and LBP-DOX nanoparticles gradually decreases at 25 °C. Under the same strain, the storage modulus (G') and loss modulus (G″) of LBP-DOX nanoparticles were inferior to LBP. The DOX release from LBP-DOX nanoparticles was pH-dependent and was accelerated by decreasing pH. Cytotoxicity study showed that the LBP-DOX nanoparticles have significantly enhanced cytotoxicity in vitro, especially for human Hepatic cancer cell line HepG2.