A microfluidics approach for the isolation of nucleated red blood cells (NRBCs) from the peripheral blood of pregnant women.

OBJECTIVE Nucleated red blood cells (NRBCs) have been identified in maternal circulation and potentially provide a resource for the monitoring and diagnosis of maternal, fetal, and neonatal health and disease. Past strategies used to isolate and enrich for NRBCs are limited to complex approaches that result in low recovery and less than optimal cell purity. Here we report the development of a high-throughput and highly efficient microfluidic device for isolating rare NRBCs from maternal blood. MATERIAL AND METHODS NRBCs were isolated from the peripheral blood of 58 pregnant women using a microfluidic process that consists of a microfluidic chip for size-based cell separation and a magnetic device for hemoglobin-based cell isolation. RESULTS The microfluidic-magnetic combination removes nontarget red blood cells and white blood cells at a very high efficiency (approximately 99.99%). The device successfully identified NRBCs from the peripheral blood of 58/58 pre-termination samples with a mean of 37.44 NRBC/mL (range 0.37-274.36 NRBC/mL). These results were compared with those from previous studies. CONCLUSION The microfluidic device results in an approximate 10- to 20-fold enrichment of NRBCs over methods described previously. The reliability of isolation and the purity of the NRBC product have the potential to enable the subsequent application of molecular diagnostic assays.