In Situ Electroporation on PERFECT Filter for High-Efficiency and High-Viability Tumor Cell Labeling.

Labeling-assisted visualization is a powerful strategy to track circulating tumor cells (CTCs) for mechanism study (e.g., tumor metastasis). Due to the rarity of CTCs in the whole blood, efficient simultaneous enrichment and labeling of CTCs are needed. Hereby, novel in situ electroporation on a previously-developed micropore-arrayed filter (PERFECT filter) is proposed. Benefiting from the ultra-small-thickness and high-porosity of the filter plus high precision pore diameter, target rare tumor cells were enriched with less damage and uniform size distribution, contributing to enhanced molecular delivery efficiency and cell viability in the downstream electroporation. Various biomolecules (e.g., small molecule dyes, plasmids, and functional proteins) were used to verify this in situ electroporation system. High labeling efficiency (74.08 ± 2.94%) and high viability (81.15 ± 3.04%, verified via live/dead staining) were achieved by optimizing the parameters of electric field strength and pulse number, ensuring the labeled tumor cells can be used for further culture and down-stream analysis. In addition, high specificity (99.03 ± 1.67%) probing of tumor cells was further achieved by introducing fluorescent dye-conjugated antibodies into target cells. The whole procedure, including cell separation and electroporation, can be finished quickly (<10 min). The proposed in situ electroporation on the PERFECT filter system has great potential to track CTCs for tumor metastasis studies.