CD44 Receptor-Guided Hyaluronic Acid Nanogels with Dual-Stimuli Responsiveness and Lysosomal Disruption Capability for In Vivo Protein Delivery in Lung Cancer Treatment

Protein delivery nanosystems must balance stable loading, barrier navigation, and targeted, controlled release. Herein, a pH/ROS dual-responsive nanogel (PRNG) was constructed by forming dynamic boronic ester crosslinkers between PEGylated hyaluronic acid bearing diethylenetriamine-grafted-catechol groups (PEG-HA-Dien-CA) and hyaluronic acid-conjugated phenylboronic acid (HA-PBA) for cytoplasmic cytochrome c (CC) delivery. This pioneering conceptual design not only facilitates the formation of stable nanocarriers with a high CC loading capacity, but also presents a distinctive mechanism for dual-responsive protein release. Confocal imaging confirmed that CC-loaded PRNG was efficiently internalized by A549 cells through CD44-dependent endocytosis, rapidly released from the endo/lysosomal compartments, and effectively delivered CC into the cytoplasm, and subsequently induced cell apoptosis in the acidic tumor microenvironment (TME) rich in H2O2. In mice bearing human lung tumors, CC-loaded PRNGs preferentially accumulate at tumor sites and effectively inhibit growth with minimal systemic toxicity, demonstrating a versatile nanoplatform for lung cancer therapy.