Magnetic Genetically Engineered Cells Constructed via Microfluidic Squeezing for Highly Efficient Capture of Circulating Tumor Cells

Abstract Circulating tumor cell (CTC) detection is crucial for early cancer diagnosis and real‐time metastasis monitoring. Conventional immunomagnetic nanomaterials (IMNs) used for CTC enrichment face limitations such as low purity and inefficiency. Although cell membrane‐coated IMNs have been explored to reduce nonspecific leukocyte binding, challenges persist, including high membrane consumption, low encapsulation efficiency, and unpredictable membrane orientation. Here, polyethyleneimine‐coated magnetic nanoparticles (PEI‐MNPs) loaded with a plasmid encoding an anti‐EpCAM single‐chain variable fragment (scFv) is developed. To enhance intracellular delivery, a microfluidic chip with a fluidic channel oriented perpendicular to the main narrow channel, inducing transient cellular deformation and improving nanoparticle uptake is designed. Once internalized, the PEI‐MNPs facilitate intracellular expression of anti‐EpCAM scFv, enabling precise recognition and magnetic separation of CTCs. This streamlined microfluidic approach achieves high‐throughput, efficient magnetic loading, and genetic engineering of target cells. This method significantly improves CTC enrichment, yielding a purity of 91.9%, compared to 61.2% with commercially available IMNs. By utilizing intact cells as biomimetic carriers for IMN encapsulation, this strategy effectively mimics receptor‐ligand interactions in vivo and minimizes nonspecific leukocyte adsorption. This work presents a novel and efficient approach for high‐purity CTC isolation, offering promising potential for early cancer diagnosis and metastasis monitoring.