Multivalent capture of circulating tumor cells using tetrahedral DNA framework-targeted nanomagnetic beads integrated microfluidic device

Abstract

Circulating tumor cells (CTCs), though rare and highly heterogeneous, are closely associated with tumor initiation, progression, and prognosis. Their low abundance, structural fragility, phenotypic diversity, and size variability make efficient enrichment particularly challenging. To address these limitations, we developed a novel CTC isolation platform that combines tetrahedral DNA nanostructure-based trivalent aptamer magnetic nanospheres (TDF-Cocktail-MNP) with a magnetic microfluidic separation device. This system enhances the capture of viable, phenotypically diverse CTCs and supports reliable downstream analysis. The TDF structure presents three aptamers: EpCAM targets epithelial CTCs, Vimentin captures mesenchymal types, and EGFR binds to cells overexpressing EGFR—a key marker in triple-negative breast cancer. This multi-target approach enables efficient isolation of heterogeneous CTC populations from whole blood samples. Captured CTCs are enriched using the IsoFlux System, which reduces mechanical stress and preserves cell viability by avoiding repeated magnetic manipulation. After nuclease-mediated removal of the DNA scaffold, cells are classified and quantified through immunocytochemistry. Validated with both spiked and clinical breast cancer samples, this platform shows strong potential for liquid biopsy applications, offering robust CTC detection and valuable insights for personalized cancer diagnostics and treatment.