Identification of fetal aneuploidy with dual‐probe fluorescence in situ hybridization analysis in circulating trophoblasts after enrichment using a high‐sensitivity microfluidic platform

Abstract

Objective: To evaluate a microfluidics-based positive selection technology for isolating circulating trophoblasts (CTs) from peripheral blood of women whose pregnancies are affected by aneuploidy and to evaluate fetal karyotype using fluorescence in situ hybridization (FISH).Method: Ten 18-ml samples of peripheral blood were collected consecutively from pregnant women whose fetus was affected by aneuploidy. A preservation buffer was added, and the specimens were shipped overnight to the testing laboratory at ambient temperature. The specimen was infused into the fully automated microfluidics-based LiquidScan ® instrument without pre-processing. This instrument contains microfluidic chips, which are coated with antibodies (anti-huEpCAM and a proprietary antibody mixture) specific to CT surface epitopes. FISH analysis was performed on the enriched cells.Results: Fetal aneuploidy evaluated included trisomy 21 (n = 3), trisomy 18 (n = 1), trisomy 13 (n = 1), monosomy X (n = 3), and triploidy (n = 1). CTs for analysis by FISH were identified in all samples. The average number of mononucleate cells per 1 ml of whole blood was 2.11 (range 0.38-4.63) overall and was 2.67 (range 1.13-4.63) using the proprietary combination of antibodies. FISH results were concordant with the aneuploidy based on other testing in all cases. Multinucleate cells were searched for and identified in the last seven samples (average number: 0.84/1 ml). Conclusions:Our study demonstrates that the LiquidScan ® , a high-sensitivity microfluidic platform, can enrich circulating trophoblasts (mononucleate and multinucleate). FISH can then be used to detect fetal aneuploidy. Key pointsWhat is already known about this topic? � Fetal trophoblasts are found in maternal circulation during pregnancy � Existing methods used to enrich circulating trophoblasts are time-intensive and expensive

Recent Advances of Microfluidic Platform for Cell Based Non-Invasive Prenatal Diagnosis

“…The immunoaffinity approach is the most common microfluidic method to isolate CFCs for NIPD. Nearly half of these studies targeted fnRBCs for NIPD [ 19 , 22 , 23 ], and the other half targeted EVTs [ 20 , 24 , 25 , 26 ]. Only one study performed analysis of both fnRBCs and fEVT [ 21 ].…”

“…More cfEVTs were obtained by antibody mixture than anti-EpCAM antibodies with an average of 2.67 cells vs. 2.11 cells from per mL of blood, respectively. Nine cases of fetal aneuploidies were successfully diagnosed by FISH on the isolated cfEVTs [ 24 ].…”

“…There are two different principles of immunoaffinity approach were used for the enrichment of fnRBCs or fEVTs. One relies on the interaction of biotin-streptavidin biological bonds [ 21 , 23 , 34 , 35 ], and the other is based on the interaction between antibody and antigen [ 19 , 20 , 22 , 24 ]. The design and fabrication of nanostructures of the chips aims to increase the contact area between chip and cells in order to increase the efficiency of cell capturing as well as maintain the integrity of cell morphology.…”