DNA-inspired conjugated polymer biointerface for selective tumor cell capture and noninvasive release

Circulating tumor cells (CTCs) are promising biomarkers for liquid biopsies in early cancer detection and monitoring, but their rarity and phenotypic heterogeneity make selective capture and non-destructive release challenging. Herein, we designed a novel DNA-inspired three-dimensional (3D) conjugating polymer-aptamer biointerface for selective capture and fringe-field pulsed electric field (FF-PEF)-triggered release of CEA-positive tumor cells. The platform was prepared by facile dip-coating a poly (para-aminophenol-co-thiophene) (PpAPT)-polyurethane (PU) blend onto a nonwoven carbon fabric (NCF) and was functionalized with carcinoembryonic antigen (CEA)-specific DNA aptamer to produce CEA/PpAPT-PU@NCF. The conjugated backbone and polar group (-OH/-NH₂/-S-) functionalities of PpAPT, together with conductive fibrous 3D substrate, provided a hydrated and nucleic-acid-compatible interface for stable aptamer immobilization, low nonspecific binding and acceptable hemocompatibility. The CEA/PpAPT-PU@NCF composite exhibited high capture efficiency rate of 93% for CEA-positive HCT116 cells, with low nonspecific adhesion. More significantly, captured cells were released under optimized FF-PEF conditions, achieving up to 62.65% release efficiency through field-driven interfacial perturbation while preserving cell viability. These results demonstrate that CEA/PpAPT-PU@NCF provides a scalable platform for selective tumor-cell capture and non-destructive release, offering potential for liquid biopsy, downstream cellular analysis, and next-generation of bioelectronics applications.