Nano-Drug Delivery Systems for Tumor Therapy: A Review of Design Strategies, Evaluation, and Mechanisms

Traditional cancer chemotherapy remains limited by serious systemic toxicity, poor tumor targeting, and multidrug resistance, resulting in unsatisfactory clinical therapeutic outcomes. Nano-drug delivery systems, featuring tunable physicochemical properties, EPR-mediated tumor accumulation and tumor microenvironment responsiveness, have emerged as a promising strategy to overcome these limitations. However, existing studies focus on individual material optimization, lacking a systematic synthesis of the complete research paradigm. This paper adopts literature induction and comparative analysis to examine the complete research paradigm of tumor-targeted nano-delivery systems. It compares four mainstream nanocarrier platforms, including lipid-based, polymer-based, inorganic, and hybrid systems. It then evaluates their design strategies, physicochemical properties, in vitro cellular uptake and cytotoxicity assays, and in vivo therapeutic efficacy and biosafety verification. Furthermore, this paper clarifies the core mechanisms underlying targeted delivery, pH/redox-responsive drug release, multidrug resistance reversal and synergistic multi-modal therapy. The reviewed studies indicate that rationally designed nano-drug delivery systems can enhance drug accumulation in tumors, reduce off-target systemic toxicity, and improve therapeutic outcomes. The systematic synthesis offers valuable references and identifies key directions for the rational design, performance optimization and clinical translation of high-efficiency, low-toxicity anti-tumor nanoformulations.