Engineering of pH/GSH-responsive nanoparticles based on a poly-γ-glutamic acid/chitosan core-shell architecture for...

In this study, we engineered pH/glutathione dual-responsive nanoparticles (LP/CC-Cu-Cur NPs) based on a poly-γ-glutamic acid (γ-PGA)/chitosan (CS) core-shell architecture for synergistic chemo/chemodynamic therapy of glioma. The nanoparticles feature a core of CC-Cu-Cur NPs, formed via Cu²⁺-coordinated self-assembly of caffeic acid-grafted CS and curcumin (Cur), encapsulated within a phenylboronic acid-conjugated γ-PGA shell through pH-sensitive borate ester bonds. Surface modification with lactoferrin conferred brain-penetrating and glioma-targeting capabilities. The resulting spherical nanoparticles had a uniform size of 235.89 nm, a zeta potential of -22.66 mV, and high Cur loading (6.02%) and encapsulation efficiency (83.09%). Upon exposure to the acidic tumor microenvironment, the nanoparticle shell detaches, reversing surface charge from negative to positive, thereby enhancing cellular uptake and mitochondrial targeting. Intracellular glutathione then triggers core degradation, releasing Cur and Cu²⁺. Cur induces mitochondrial apoptosis, while Cu²⁺ catalyzes a Fenton-like reaction, converting endogenous hydrogen peroxide into highly cytotoxic reactive oxygen species. In vitro, the nanoparticles showed enhanced blood-brain barrier penetration, efficient lysosomal escape, and potent cytotoxicity against GL-261 cells (IC₅₀ = 18.34 μg/mL) via a synergistic action of Cu²⁺ and Cur (CI = 0.28). In vivo, LP/CC-Cu-Cur NPs achieved superior brain accumulation and antitumor efficacy, highlighting their potential as a promising strategy for glioma therapy.