Cascade Cell-Assisted Enhanced Fluorescence Strategy for Highly Sensitive Detection of Lung Adenocarcinoma Cells in Whole Blood.

Circulating tumor cells (CTCs) serve as critical biomarkers for diagnosis, treatment monitoring, and prognosis evaluation of lung cancer. However, their trace abundance in blood makes the development of integrated technologies for CTCs isolation, enrichment, and detection with both high specificity and sensitivity a key bottleneck for clinical translation. This study proposed a novel cascade cell-assisted enhanced fluorescence strategy that integrates dual-targeting recognition, cell-mediated cascade assembly, and enzymatic amplification. This dual-targeting strategy achieves efficient capture and enrichment of human non-small cell lung cancer cell line A549 cells through EpCAM antibodies, and uses dual-aptamer probe-mediated EGFR recognition to further improve detection specificity. Subsequently, cascade assembly of acute lymphoblastic leukemia CCRF-CEM cells around target cells combined with enzyme-catalyzed signal amplification constructed a highly sensitive fluorescence-based detection system, with a linear range of 10-104 cells/mL, a limit of detection (LOD) as low as 10 cells/mL, and recovery rates of 94.25%-105.41%. Importantly, clinical validation using whole blood samples from lung adenocarcinoma patients (n = 30) and healthy donors (n = 23) showed significant differentiation (P < 0.05, AUC of 0.728), underscoring its diagnostic potential. Moreover, its modular expandability allows extension to other tumor CTCs detection by replacing target recognition units.