An integrated microfluidic platform for negative selection and enrichment of cancer cells

Circulating tumor cells (CTCs), tumor cells that disseminate from primary tumors to the bloodstream, have recently emerged as promising indicators for cancer diagnosis and prognosis. However, the technical difficulties in isolating and detecting rare CTCs have limited the widespread applicability of this method to date. In this work, a new integrated microfluidic system integrating micromixers and micropumps capable of performing 'negative selection and enrichment' of CTCs was developed. By using anti-human CD45 antibodies-coated magnetic beads, leukocytes were effectively removed by applying an external magnetic force, leaving behind an enriched target cell population. The on-chip CTC recovery rate was experimentally found to be 70 ± 5% after a single round of negative selection and enrichment. Meanwhile, CD45 depletion efficiency was 83.99 ± 1.00% and could be improved to 99.84 ± 0.04% after three consecutive rounds of depletion. Notably, on-chip negative selection and enrichment was 58% faster and the repeated depletion could be processed automatically. These promising results suggested the developed microfluidic chip is potentiated for a standardized CTC isolation platform.