ZnO-Based Nanoparticles for Targeted Cancer Chemotherapy and the Role of Tumor Microenvironment: A Systematic Review
Vasilis‐Spyridon Tseriotis, Dimitrios Ampazis, Sofia Karachrysafi, Theodora Papamitsou, Georgios Petrakis, Dimitrios Kouvelas, Paraskevas Mavropoulos, Konstantinos Lallas, Aleksandar Sič, Vasileios Fouskas, Konstantinos I. Stergiou, Pavlos Pavlidis, Marianthi Arnaoutoglou
Abstract
Cancer, a leading global cause of death responsible for nearly 10 million deaths annually, demands innovative therapeutic strategies. Intrinsic cytotoxicity and biocompatibility of zinc oxide nanoparticles (ZnO-NPs) have rendered them promising nanoplatforms in oncology. We herein systematically review their applications for targeted cancer chemotherapy, with a focus on physicochemical properties, drug delivery mechanisms, and interactions with the tumor microenvironment (TME). We searched PubMed, SCOPUS, and Web of Science from inception through December 2024 for peer-reviewed preclinical studies on cancer models. Results were qualitatively synthesized. Quality was assessed with the SYRCLE risk of bias tool. Among 20 eligible studies, ZnO-NPs were frequently functionalized with ligands to enhance tumor targeting and minimize systemic toxicity. Chemotherapeutic agents (doxorubicin, 5-fluorouracil, docetaxel, cisplatin, gemcitabine, and tirapazamine) were loaded into ZnO-based carriers, with improved anticancer efficacy compared to free drug formulations, particularly in multidrug-resistant cell lines and in vivo murine xenografts. The mildly acidic TME was exploited for pH-responsive drug release, premature leakage reduction, and improvement of intratumoral accumulation. Enhanced therapeutic outcomes were attributed to reactive oxygen species generation, zinc ion-mediated cytotoxicity, mitochondrial dysfunction, and efflux pump inhibition. Deep tumor penetration, apoptosis induction, and tumor growth suppression were also reported, with minimal toxicity to healthy tissues. ZnO-NPs might constitute a versatile and promising strategy for targeted cancer chemotherapy, offering synergistic anticancer effects and improved safety profiles. Future studies emphasizing long-term toxicity, immune responses, and scalable production could lead to clinical translation of ZnO-based nanomedicine in oncology.