Dual pH/ROS‐Responsive Nanoplatform with Deep Tumor Penetration and Self‐Amplified Drug Release for Enhancing Tumor Chemotherapeutic Efficacy

Poor deep tumor penetration and incomplete intracellular drug release remain challenges for antitumor nanomedicine application in clinical settings. Herein, a nanomedicine (RLPA‐NPs) is developed that can achieve prolonged blood circulation, deep tumor penetration, active‐targeting of cancer cells, endosome/lysosome escape, and intracellular selectivity self‐amplified drug release for effective drug delivery. The RLPA‐NPs are constructed by encapsulation of a pH‐sensitive polymer octadecylamine‐poly(aspartate‐1‐(3‐aminopropyl) imidazole) (OA‐P(Asp‐API)) and a ROS‐generation agent, β‐Lapachone (Lap), in micelles assembled by the tumor‐penetration peptide internalizing RGD (iRGD)‐modified ROS‐responsive paclitaxel (PTX)‐prodrug. iRGD could promote RLPA‐NPs penetration into deep tumor tissue, and specific targeting to cancer cells. After internalization by cancer cells through receptor‐mediated endocytosis, OA‐P(Asp‐API) can rapidly protonate in the endosome's acidic environment, resulting in RLPA‐NPs escape from the endosome through the “proton sponge effect”. At the same time, the RLPA‐NPs micelle disassembles, releasing Lap and PTX‐prodrug. Subsequently, the released Lap could generate ROS, consequently amplifying and accelerating PTX release to kill tumor cells. The in vitro and in vivo studies demonstrated that RLPA‐NPs can significantly improve the therapeutic effect compared to control groups. Therefore, RLPA‐NPs are a promising nanoplatform for overcoming multiple physiological and pathological barriers to enhance drug delivery. Multiple physiological and pathological barriers have greatly limited the application of nanomedicine in clinical settings. Herein, a pH/reactive oxygen species dual‐responsive drug delivery system is synthesized which can achieve prolonged blood circulation, deep tumor penetration, active‐targeting of cancer cells, endosome/lysosome escape and intracellular selectivity self‐amplified drug release. This drug delivery system provides a strategy for effective cancer therapy.