Enrichment of circulating trophoblasts from maternal blood using laminar microscale vortices.

Objective: Enrichment of circulating trophoblasts (CTs) from maternal blood at week 11-13 of gestation, using laminar microscale vortices, and evaluation of the performance of the VTX-1 Liquid Biopsy System in terms of CT recovery and purity.

Method: Eight mililiter of blood was collected from 15 pregnant women and processed with the VTX-1 Liquid Biopsy System. Y-chromosome specific quantitative PCR was performed to estimate the number of enriched male CTs. To evaluate the VTX-1 performance, the target cell recovery was characterized by spiking experiments with a trophoblast cell line. Furthermore, the total quantity of DNA after enrichment was used to calculate the number of retained maternal cells.

Results: Successful recovery of male CTs was established in 7 out of 10 first trimester samples from pregnant women carrying a male fetus. The number of CTs, recovered from 8 ml of blood, was estimated between two and six. Spiking experiments resulted in a CT recovery of ±35 % with ±1524 retained maternal blood cells.

Conclusion: CTs can be enriched from maternal blood with high purity, using laminar microscale vortices, starting from 8 ml of blood.