Self-Assembly Regulation, Drug Release Behavior, Anti-Multidrug Resistance of Redox-Responsive Gemcitabine–Quinine Nanoassemblies in Glioblastoma Therapy

of 1.560 ± 0.123 μM in U251 cells─7-fold and 2.7-fold lower than that of free Gem and GQ-C NPs, respectively. Mechanistic studies revealed that GQ-S NPs induced apoptosis and markedly suppressed P-gp expression, and promoted intracellular Gem accumulation. In summary, GQ-S NPs integrate the advantages of carrier-free design, low toxicity, high stability, and redox-responsive release, offering a promising strategy for targeted combination therapy in drug-resistant glioblastoma.