Abstract
Early and accurate detection of cancer biomarkers is essential for improving patient survival and advancing precision medicine. Electrochemical biosensors have emerged as promising diagnostic platforms due to their high sensitivity, rapid response, low cost, and compatibility with miniaturized and point-of-care systems. Recent advances in nanomaterials have significantly enhanced sensor performance by improving electrode conductivity, increasing electroactive surface area, enabling efficient bioreceptor immobilization, and facilitating signal amplification. This review presents a comprehensive and critical overview of nanomaterial-enabled electrochemical biosensors for cancer diagnostics. The fundamental principles of electrochemical biosensing and key transduction modes—voltammetric, amperometric, impedimetric, potentiometric, and photoelectrochemical—are systematically discussed. Particular attention is given to clinically relevant biomarkers, including proteins, nucleic acids, exosomes, metabolites, and circulating tumor cells, as well as their detection challenges in complex biological matrices. Recent progress in signal amplification strategies is highlighted, including nanomaterial-based interfaces, catalytic and enzyme-assisted systems, redox probes, and nucleic acid amplification techniques, enabling ultra-low detection limits. Key performance parameters, multiplexing approaches, and integration with liquid biopsy are also addressed. Current challenges such as biofouling, interfacial instability, reproducibility, and scalability are critically evaluated. Future directions focus on advanced nanomaterial design, robust interfaces, scalable fabrication, and integration with microfluidics, wearable systems, and digital analytics.