Aptamer-functionalized nanomaterials for circulating tumor cell detection: From liquid biopsy to cancer theranostic

Circulating tumor cells (CTCs) are important biomarkers in liquid biopsy for early cancer screening, prognosis evaluation, treatment monitoring, and prediction of metastatic risk; however, their extremely low abundance and pronounced heterogeneity remain major barriers to sensitive and reliable analysis. Aptamers have emerged as promising recognition ligands for CTC targeting owing to their high affinity and specificity, facile synthesis, and straightforward chemical modification. Meanwhile, nanomaterials offer unique optical, electrical, magnetic, and thermal properties that facilitate signal amplification, target enrichment, and the construction of multifunctional platforms. The integration of aptamers and nanomaterials has thus provided a versatile framework for the development of high-performance CTC detection systems and targeted cancer theranostic platforms. This review summarizes recent progress in aptamer-functionalized nanomaterials for CTC-related applications, including aptamer selection and optimization, CTC capture, separation, detection, and imaging, as well as their expanded applications in photothermal therapy, photodynamic therapy, and drug delivery. Representative noble-metal, carbon-based, semiconductor, organic, and composite nanoplatforms are further compared, with an emphasis on their functional advantages and current limitations. Finally, outstanding challenges in analytical robustness, biosafety, in vivo delivery, and clinical translation are discussed, and future directions toward multiplexed analysis, dynamic monitoring, and personalized precision oncology are highlighted.