Surface engineering of liposomes with quaternized hyaluronate for reduced toxicity and enhanced doxorubicin delivery

Liposomes (LPs) are widely used in biomedical applications but suffer from poor physiological stability, dose-dependent cytotoxicity, and rapid clearance. To overcome these challenges, we developed quaternized hyaluronate-coated cationic liposomes (QHA-LPs) for enhanced stability and cell interactions. QHA-LPs are polyampholytic, carrying both positive charges introduced through quaternization and the native negative charges retained from the HA backbone. This quaternization strategy produced QHA-LPs (∼140 nm) with significantly improved colloidal stability compared to native HA-LPs. Consequently, the QHA-LPs maintained colloidal stability, retained >90% CRL2522 fibroblast viability at concentrations up to 200 µg mL^-1, achieved 92.3 ± 7.5% DOX encapsulation efficiency, and showed more than two-fold higher MCF-7 uptake compared to uncoated LPs and HA-LPs. In MCF-7 cells, the DOX-loaded QHA-LPs showed the lowest IC₅₀ (0.17 µM) among all formulations tested, approximately three-fold lower than that of free DOX (0.50 µM). In A549 cells, all liposomal formulations showed lower IC₅₀ values than free DOX, with NaHA-LPs/DOX showing the lowest IC₅₀ (0.12 ± 0.06 µM), followed by QHA-LPs/DOX (0.16 ± 0.05 µM), consistent with CD44-mediated and charge-mediated uptake in a cell-type-dependent manner. These in vitro observations demonstrated the stability of the QHA-LPs under the tested pH conditions for carrier DOX delivery, though this remains to be evaluated in vivo.