Enrichment and Identification of Fetal Nucleated Red Blood Cells from Maternal Blood with Magnetic Nanoparticles and Quantum Dots

摘要

Utility of fetal nucleated red blood cells (FNRBCs) in maternal circulation has been considered as a promising strategy for non-invasive prenatal diagnosis (NIPD). However, FNRBCs in maternal blood are rare and difficult to be separated from maternal blood. Herein, we report a new approach to obtain FNRBCs from maternal blood by magnetic nanoparticles (MNPs) and quantum dots (QDs). Anti-CD71 antibodies were coupling to the surface of the MNPs (150-200 nm in diameter) using the carbodiimide-mediated condensation method. The anti-CD71-MNPs conjugates maintained good magnetic responsivity and antibody activity, and enriched effectively nucleated red blood cells (NRBCs) from model mixture combined umbilical cord blood and healthy non-pregnant female blood. Anti-gamma-globin antibodies were conjugated to the surface of the red CdTe-QDs using carbodiimide-mediated coupling. The anti-gamma-globin-QDs exhibited strong red emission at 630 nm with a quantum yield of similar to 53%. Cells imaging studies demonstrated the QDs were effective as fluorescent probes for labeling NRBCs from umbilical cord blood. Finally, 10 mL of maternal blood samples from 25 candidates were collected and treated by density centrifugation and anti-CD71MNPs, and FNRBCs were successfully identified by anti-gamma-globin-QDs in 24 out of 25 samples. In conclusion, a novel method for obtaining FNRBCs from maternal blood was established based on nanoparticles, which provides a new strategy for NIPD.