Preparation of hyaluronic acid nanospheres with synergistic charge reversal and active targeting for enhanced selective anticancer drug delivery

Abstract

The development of smart nanocarriers that can respond synergistically to the tumor microenvironment (TME) and actively target cancer cells is pivotal for advancing precision oncology. Herein, we report the design and preparation of multifunctional hyaluronic acid (HA) nanospheres engineered for synergistic charge reversal and active targeting to achieve enhanced selective anticancer drug delivery. A novel copolymer, tetraphenylethylene-hyaluronic acid-polylysine-dimethylmaleic acid (TPE-HA-PLL(DMMA)), was synthesized and self-assembled into uniform nanospheres (THPD NPs) in aqueous solution. This system integrates multiple functionalities: the aggregation-induced emission (AIE) property of TPE for self-assembly and potential imaging, the CD44-targeting capability of HA for active tumor homing, and the pH-sensitive charge reversal of PLL(DMMA) for TME-responsive uptake. Doxorubicin (DOX) was efficiently encapsulated, yielding DOX@THPD NPs with a high drug loading content of 27.2%. The nanospheres demonstrated a distinct charge reversal from −20.2 mV under physiological conditions (pH 7.4) to +25.8 mV in the weakly acidic TME (pH 6.8), thereby facilitating enhanced cellular internalization. In vitro studies revealed a synergistic effect: the combination of CD44-mediated active targeting and charge reversal significantly boosted intracellular DOX delivery in CD44-overexpressing HCT116 cells, increasing the uptake rate from 53% to 69%. Consequently, DOX@THPD NPs exhibited potent and selective cytotoxicity against cancer cells while maintaining high biocompatibility. This work presents a robust strategy for crafting intelligent HA-based nanocarriers, highlighting the powerful synergy between multiple targeting mechanisms for effective and selective cancer therapy.