ZnO Nanostructure-Based Biosensors in Cancer Detection: Synthesis, Mechanisms, and Future Perspectives

Cancer remains a leading global health challenge, with early detection critical in improving patient outcomes. Zinc oxide (ZnO) nanostructure-based biosensors have emerged as a promising solution due to their high sensitivity, biocompatibility, and flexible transduction mechanisms. This review highlights the recent advancements in ZnO biosensors for cancer detection, focusing on synthesis methods, biosensing mechanisms, and performance metrics. A solution-based and vapour-phase technique for fabricating ZnO nanostructures is compared, emphasising their effect on morphology, crystallinity, and sensing performance. Electrochemical, optical, and piezoelectric mechanisms are explored, showing ZnO’s ability to detect biomarkers such as CA-125, CYFRA 21–1, and sarcosine with ultra-low detection limits. Innovations in multimodal sensing and integration with portable platforms are discussed, along with challenges in stability, scale-up production, and clinical translation. The review concludes with recommendations for future directions, supporting the improvement of material engineering, point-of-care usage, and machine learning integration to advance ZnO-based biosensors for earlier cancer diagnosis. These developments hold great potential to transform cancer diagnostics, providing rapid, non-invasive, and low-cost solutions to global healthcare.