Nanomaterial-Enabled Electrochemical Biosensing Platforms for Circulating Tumor Cell Analysis

Circulating tumor cells (CTCs) are valuable liquid biopsy markers for assessing tumor heterogeneity, monitoring minimal residual disease (MRD), and guiding personalized therapy. However, their rarity in blood and phenotypic changes during epithelial-mesenchymal transition (EMT) limit reliable detection. Electrochemical interfacial biosensors offer a promising solution due to their high sensitivity, miniaturization potential, and compatibility with microfluidics. This review summarizes recent advances in nanomaterial-enabled electrochemical CTC biosensing, focusing on interface engineering, signal transduction, and clinical translation. We highlight strategies such as multivalent recognition, engineered nanotopography, antifouling interfaces, and stimulus-responsive release that enhance CTC capture in whole blood. We also discuss nanozyme-based amplification, ratiometric calibration, and multiplexed electrochemical detection for phenotypic profiling beyond simple enumeration. Finally, we outline key translational requirements, including standardized benchmarking, clinical cohort validation, and artificial intelligence (AI)-assisted data analysis. Integrating nanostructured interfaces with multiplexed detection and standardized whole-blood validation may accelerate electrochemical CTC analysis toward routine, phenotype-aware liquid biopsy.