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

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.