Circulating Fetal Cells for NIPD: Comparison
Please note this is a comparison between Version 2 by Catherine Yang and Version 1 by Giulia Sabbatinelli.

Prenatal diagnosis plays a crucial role in clinical genetics. Non-invasive prenatal diagnosis using fetal cells circulating in maternal peripheral blood has become the goal of prenatal diagnosis, to obtain complete fetal genetic information and avoid risks to mother and fetus. The development of high-efficiency separation technologies is necessary to obtain the scarce fetal cells from the maternal circulation. 

  • prenatal diagnosis
  • circulating fetal cells
  • NIPD

1. Introduction

During the early stages of fetal development, some cells migrate from the fetus to the maternal circulation and may represent an interesting target for non-invasive prenatal diagnosis (NIPD).
However, despite technological advances, an effective standardized test suitable for routine clinical practice is not yet available. An obstacle is the small number of fetal cells present in the maternal circulation and their extreme fragility, which can lead to loss during sample handling and the absence of a specific fetal marker.
Non-invasive prenatal testing based on circulating fetal cell-free DNA has been commercially available since 2011 and offers the opportunity to radically change prenatal screening. However, the introduction into actual clinical practice is challenging because of cost, differences in the scope of abnormalities detectable, and integration into existing testing [1,2][1][2]. Recently, the analysis of fetal cells from peripheral maternal blood has been shown to be more effective in helping to identify fetal aneuploidy, microdeletion syndromes, hemoglobinopathy, and blood groups than cffDNA, due to their intact fetal genome, free from maternal DNA contamination [3].

2. Fetal Cell Types and Strategies for Isolation and Enrichment

Herzenberg et al. were the first to demonstrate the enrichment of fetal leukocytes from maternal blood in 1979 using fluorescence-activated cell sorting (FACS) [20][4]; however, the most studied cell types are erythroblasts (nRBCs) and trophoblasts. A summary of the types of fetal cells identified and isolated from the maternal circulation and the most commonly applied markers are shown in Table 1.
Table 1. Fetal cell lines isolated from maternal peripheral blood and markers most commonly applied for validation of NIPD.
Fetal Cell Types in

Maternal Blood
Markers Advantages Drawbacks
Lymphoid progenitors CD34 [21,22]

CD38 [21,22]
CD34 [5][6]

CD38 [5][6]
In vitro proliferation [23]In vitro proliferation [7] Long-term survival [21,22];

Not easy distinguishable from maternal cells [23]
Long-term survival [5][6];

Not easy distinguishable from maternal cells [7]
Hematopoietic stem/progenitor cells CD34 [6,[21,24,8][25,5][26,927,28]CD34 ][10][11][12][13] In vitro proliferation [23]In vitro proliferation [7] Long-term survival [21];

Not easy distinguishable from maternal cells [23]
Long-term survival [5];

Not easy distinguishable from maternal cells [7]
Mesenchymal stem cells Vimentin [25,29]

Fibronectin [25]

Vascular cell adhesion molecule [25,28]

CD14 [

CD45 [
10][1425,29]Vimentin ]

Fibronectin [10]

Vascular cell adhesion molecule [10][13]

CD14 [10][14]

CD45 [10][14]
In vitro proliferation and differentiation [25,29,30];

Great therapeutical potential [25]
In vitro proliferation and differentiation [10][14][15];

Great therapeutical potential [10]
Very low number [25,29];

Relatively distinctive cell morphology (size) [39]
Passage in maternal blood is uncommon phenomenon in all pregnancies [52,53,[38][3954]; Placental origin (1% mosaicism) [][4055]Passage in maternal blood is uncommon phenomenon in all pregnancies ]; Placental origin (1% mosaicism) [41]

2.1. Trophoblast

Trophoblasts were the first cell type identified. Cytotrophoblast-derived cells are mononuclear, invade the uterine wall and spiral arteries, and spill into maternal blood.
One of the distinguishing features of trophoblastic cells is the expression of cytokeratins (CKs).
Sargent et al. and Johnson et al. used an antibody against trophoblast-specific H315 surface antigen, which later proved insufficient for adequate cell separation [44,46,47][30][32][33].
Cacheux et al. recovered trophoblasts from maternal blood using immunomagnetic leukocyte depletion and flow cytometry with the anti-trophoblast antibodies GB17 and GB25. However, Y chromosome identification by FISH showed a rate of only 4.25% [45][31]. Other studies report the use of human leukocyte G antigen to enrich circulating trophoblasts from the maternal circulation [37,38,42,50][23][24][28][36]. An additional isolation strategy was based on fetal trophoblast cell size [55][41].
The limitations currently associated with the use of these cells are their extremely low numbers in the mother’s blood. In addition, they are difficult to isolate because they become trapped in the lungs and are rapidly eliminated from the maternal circulation. Furthermore, the passage of trophoblastic cells does not appear to be a common phenomenon in all pregnancies [52,53,54][38][39][40].
The major disadvantage of using CKs and other intracellular antigens is the need to make membranes of fragile fetal cells permeable to antibody molecules.
In addition, trophoblastic cells, being of placental origin, have a 1% incidence of mosaicism, similar to that found in chorionic villus sampling (CVS) [55][41].

2.2. Erythroblast

Historically, nRBCs have been the most studied cells for NIPD. The first evidence of immature erythrocytes circulating in maternal blood dates back to 1957 in Kleinhauer’s studies [36][22]. The fnRBCs are the first hematopoietic cells to be produced during fetal development. Their passage through the maternal-placental interface is predominant over other fetal cell types, such as leukocytes and trophoblasts. They also have a short half-life (25–35 days), which does not allow their persistence in the maternal circulation [56,57][42][43]. In addition, they have a single nucleus with a complete genetic makeup and relatively specific intracellular and surface markers. Due to these characteristics, fnRBCs appear highly interesting targets for NIPD [6][8].

3. New Approaches

In fetal cell isolation, microfluidics allows the separation of cells based on size, deformability, and electrical and optical properties [75,76][44][45]. Antibodies with specific cellular markers can also be used [77][46]. Wang et al. were able to isolate 24 fnRBCs per milliliter of maternal blood in media using gelatin-coated microspheres, with anti-CD147 as a specific recognition molecule. Cells that bind to the microspheres are separated through a spiral microfluidic chip, based on the size difference between the microspheres binding fnRBCs and white blood cells. The release of fetal cells from the microspheres is achieved by enzymatic treatment. A fetal cell capture efficiency of approximately 81%, a purity of 83%, and a viability of cell release >80% were calculated using spiked samples [78][47]. The technology is very suggestive, and robust evidence is needed about its practical application when tested on a large series of patients.
Another fascinating technological innovation is the Cell RevealTM system, a silicon-based nanostructured microfluidic that uses immunoaffinity to capture trophoblasts and fnRBCs with specific antibodies. Huang et al. tested this technology, isolating 14–32 fnRBCs/4 mL and 1–44 EVT/4 mL of maternal blood. The fetal origin of the cells was confirmed by FISH on chip. The identified cells were retrieved by an automated cell harvester for molecular genetic analysis, such as comparative genomic array hybridization (aCGH) and next-generation sequencing (NGS) [79][48]. The cell capture rate was evaluated in spiking assays and estimated to be 88.1% [80][49].
In a recent study, Gur et al. presented a two-tiered microchip system that reduces sample preparation steps while implementing purity, using ETVs model cell lines. The system allows for direct processing of a whole blood sample and appears versatile enough to target a variety of antigens to achieve a high rate of cell recovery [81][50].
Microfluidic techniques are already used in many laboratories because of the considerable advantages they present, all of which are derived from the small volumes of liquid treated, high control of flow, less time needed to analyze a product, lower costs of reagents and waste products, greater control of concentrations and molecular interactions, and the possibility of performing parallel processes. Further development of such devices appears to be very promising.
However, limitations of approaches based on microfluidic systems remain, including the inability to directly process a standard tube of blood sample without an initial volume reduction step, the use of a single antibody for cell capture, and the retrieval of cells individually for downstream analysis [82][51]. In Table 2 a list of approaches for fetal cell isolation/enrichment is reported.
Table 2.
 A summary of technical approaches of isolation or enrichment of fetal cells in the maternal circulation.
Fetal Cell Type Isolation/Enrichment Technique Purity and Recovery Rates References
fnRBCs MACS N/A [34,41,83][20][27][52]
FACS N/A [58][53]
Density gradient centrifugation 82 ± 6.4% purity [51]

84 ± 4% recovery rate [51]

32.5 ± 11.6 recovered cells [61]
82 ± 6.4% purity [37]

84 ± 4% recovery rate [37]

32.5 ± 11.6 recovered cells [54]

Engraftment in maternal tissue soon after transplacental passage [29]
Very low number [10][14];

Engraftment in maternal tissue soon after transplacental passage [14]
Leukocytes HLA antigens [20,28,31,32]

CD45 [28,33]
HLA antigens [4][13][16][17]

CD45 [13][18]
Transplacental passage [4];

In vitro proliferation [4]
Transplacental passage [19];

In vitro proliferation [19]
Long persistence in maternal blood [21
High molecular filter method 46.3 ± 25.1 recovered cells [71][59]]Long persistence in maternal blood [5]
Nucleated red blood cells ζ and ε chain of embryonic Hb [34,35,36,37]

γ chain of HbF [36]

CD71 [38,]

4B9 [

i-antigen [

CD147 [

Gly A [
[39]ζ and ε chain of embryonic Hb [2022][23]

γ chain of HbF [22]
Morphology-based micromanipulation

CD71 [24][25]

4B9 [28]

i-antigen [24]

CD147 [29]

Gly A [25]
Short half-life [6];

Single nucleus [6];

Early appearance in maternal blood [6];

Surface and intracellular markers [34,36,37,38,39,41,42,43]
Short half-life [8];

Single nucleus [
Average 4.1 recovered cells [848];

Early appearance in maternal blood [8];

Surface and intracellular markers
][60][20][22][23][24][25][27][28][29] Low number in maternal blood [6]Low number in maternal blood [8]
Extravillous cytotrophoblasts (EVTs) H315 [44]

GB17 [45]

GB25 [45]

Cytokeratins [49,50]

CD141 [51]
H315 [30]46,47,48]

CD105 [48]

Human leukocyte G antigen [

GB17 [31]

GB25 [31]

Cytokeratins [32][33][34]

CD105 [34]

Human leukocyte G antigen [35][36]

CD141 [37]
Specific intracellular markers [52
Charge flow separation 0.503 ± 0.264 purity

11,409 ± 7.684 recovered cells

Relatively distinctive cell morphology (size) [
[7353]Specific intracellular markers ][61]
Lateral magnetophoretic microseparator 87.8% purity

1–396 recovered cells
Microfluidics 83% purity [68]

81% recovery rate [68]

88.17% recovery rate [70]
83% purity [63]

81% recovery rate [63]

88.17% recovery rate [64]
Hyperaggregation N/A [86][65]
Trophoblasts MACS N/A [51][37]
FACS N/A [45][31]
Isolation by size of epithelial tumor/trophoblastic cells (ISET) 50.7% recovery rate [76]

48.1% recovery rate [77]
50.7% recovery rate [45]

48.1% recovery rate [46]
Trophoblast retrieval and isolation from the cervix (TRIC) 99% purity [90]

106% ± 13 recovery rate [90]

675 (IQR, 399–1010) trophoblast yield [91]

97.9% purity [91]
99% purity [69]

106% ± 13 recovery rate [69]

675 (IQR, 399–1010) trophoblast yield [70]

97.9% purity [70]
Microfluidics 1–32 EVT/2 mL [79][48]
Fetal cells * Avidin-biotin immunoaffinity column Enrichment up to 1000-fold [92][71]
Telomerase depletion assay N/A [93][72]
data Lectin-based method 7.8 ± 8.5 recovered cells [70][64]
Ikonoscope N/A [94][73]
N/A; not available. * not otherwise identified.


  1. Cuckle, L.S.; Benn, P.; Pergament, E. Cell-free DNA screening for fetal aneuploidy as a aclinical service. Clin. Biochem. 2015, 48, 932–941.
  2. Chitty, L.S.; Wright, D.; Hill, M.; Verhoef, T.I.; Dalet, R.; Lewis, C.; Mason, S.; McKay, F.; Jenkins, L.; Howarth, A.; et al. Uptake, outcomes, and costs of implementing non-invasive prenatal testing for Down’s syndrome into NHS maternity care: Prospective cohort study in eight diverse maternity units. BMJ 2016, 354, i3426.
  3. Chen, F.; Liu, P.; Gu, Y.; Zhu, Z.; Nanisetti, A.; Lan, Z.; Huang, Z.; Liu, J.S.; Kang, X.; Deng, Y.; et al. Isolation and whole genome sequencing of fetal cells from maternal blood towards the ultimate non-invasive prenatal testing. Prenat. Diagn. 2017, 37, 1311–1321.
  4. Herzenberg, L.A.; Bianchi, D.W.; Schroder, J.; Cann, H.M.; Iverson, G.M. Fetal cells in the blood of pregnant women: Detection and enrichment by fluorescence-activated cell sorting. Proc. Natl. Acad. Sci. USA 1979, 76, 1453–1455.
  5. Bianchi, D.W.; Zickwolf, G.K.; Weil, G.J.; Sylvester, S.; DeMaria, M.A. Male fetal progenitor cells persist in maternal blood for as long as 27 years postpartum. Proc. Natl. Acad. Sci. USA 1996, 93, 705–708.
  6. Khosrotehrani, K.; Leduc, M.; Bachy, V.; Nguyen Huu, S.; Oster, M.; Abbas, A.; Uzan, S.; Aractingi, S. Pregnancy allows the transfer and differentiation of fetal lymphoid progenitors into functional T and B cells in mothers. J. Immunol. 2008, 180, 889–897.
  7. Jansen, M.W.; Korver-Hakkennes, K.; van Leenen, D.; Brandenburg, H.; Wildschut, H.I.; Wladimiroff, J.W.; Ploemacher, R.E. How useful is the in vitro expansion of fetal CD34+ progenitor cells from maternal blood samples for diagnostic purposes? Prenat. Diagn. 2000, 20, 725–731.
  8. Huang, Z.; Fong, C.-Y.; Gauthaman, K.; Sukumar, P.; Choolani, M.; Bongso, A. Novel approaches to manipulating foetal cells in the maternal circulation for non-invasive prenatal diagnosis of the unborn child. J. Cell. Biochem. 2011, 112, 1475–1485.
  9. Little, M.-T.; Langlois, S.; Wilson, R.D.; Lansdorp, P.M. Frequency of Fetal Cells in Sorted Subpopulations of Nucleated Erythroid and CD34+ Hematopoietic Progenitor Cells from Maternal Peripheral Blood. Blood 1997, 89, 2347–2358.
  10. Campagnoli, C.; Roberts, I.A.G.; Kumar, S.; Bennett, P.R.; Bellantuono, I.; Fisk, N. Identification of mesenchymal stem/progenitor cells in human first-trimester fetal blood, liver, and bone marrow. Blood 2001, 98, 2396–2402.
  11. Huu, S.N.; Dubernard, G.; Aractingi, S.; Khosrotehrani, K. Feto-Maternal Cell Trafficking: A Transfer of Pregnancy Associated Progenitor Cells. Stem Cell Rev. Rep. 2006, 2, 111–116.
  12. Mikhail, A.; Covic, A.; Goldsmith, D. Stimulating Erythropoiesis: Future Perspectives. Kidney Blood Press. Res. 2008, 31, 234–246.
  13. Klonisch, T.; Drouin, R. Fetal–maternal exchange of multipotent stem/progenitor cells: Microchimerism in diagnosis and disease. Trends Mol. Med. 2009, 15, 510–518.
  14. O’Donoghue, K.; Choolani, M.; Chan, J.; de la Fuente, J.; Kumar, S.; Campagnoli, C.; Bennett, P.R.; Roberts, I.A.G.; Fisk, N.M. Identification of fetal mesenchymal stem cells in maternal blood: Implications for non-invasive prenatal diagnosis. Mol. Hum. Reprod. 2003, 9, 497–502.
  15. de la Fuente, J.; O’Donoghue, K.; Kumar, S.; Chan, J.; Fisk, N.M.; Roberts, I.A.G. Ontogeny-related changes in integrin and cytokine production by fetal mesenchymal stem cells (MSC). Blood 2002, 100, 526a.
  16. Grosset, L.; Barrelet, V.; Odartchenko, N. Antenatal fetal sex determination from maternal blood during early pregnancy. Am. J. Obstet. Gynecol. 1974, 120, 60–63.
  17. Tharapel, A.T.; Jaswaney, V.L.; Dockter, M.E.; Wachtel, S.S.; Chandler, R.W.; Simpson, J.L.; Shulman, L.P.; Meyers, C.M.; Elias, S. Inability to detect fetal mataphases in flowsorted lynphocyte cultures based on maternal-fetal HLA differences. Fetl. Diagn. Ther. 1993, 8, 95–101.
  18. Parks, D.R.; Herzenberg, L.A. Fetal cells from maternal blood: Their selection and prospects for use in prenatal diagnosis. Methods Cell Biol. 1982, 26, 277–295.
  19. Walknowska, J.; Conte, F.; Grumbach, M. Practical and theoretical implications of fetal/maternal lymphocyte transfer. Lancet 1969, 293, 1119–1122.
  20. Ganshirt-Ahlert, D.; Burschyk, M.; Garritsen, H.S.; Helmer, L.; Miny, P.; Horst, J.; Schneider, H.P.; Holzgreve, W. Magnetic cell sorting and the transferrin receptor as potential means of prenatal diagnosis from maternal blood. Am. J. Obstet. Gynecol. 1992, 166, 1350–1355.
  21. Choolani, M.; O’Donnell, H.; Campagnoli, C.; Kumar, S.; Roberts, I.; Bennet, P.R.; Fisk, N.M. Simultaneous fetal cell identification and diagnosis by ε-globin chain immunophenotyping and chromosomal fluorescence in situ hybridization. Blood 2001, 98, 554–557.
  22. Kleinhauer, E.; Braun, H.; Betke, K. Demonstration of fetal hemoglobin in erythrocytes of a blood smear. Klin. Wochenschr. 1957, 35, 637–638.
  23. Sorensen, M.D.; Gonzalez Dosal, R.; Jensen, K.B.; Christensen, B.; Kolvraa, S.; Jensen, U.B.; Kristensen, P. Epsilon hemoglobin specific antibodies with applications in noninvasive prenatal diagnosis. J. Biomed. Biotechnol. 2009, 2009, 659219.
  24. Calabrese, G.; Baldi, M.; Fantasia, D.; Sessa, M.T.; Kalantar, M.; Holzhauer, C.; Alunni-Fabbroni, M.; Palka, G.; Sitar, G. Detection of chromosomal aneuploidies in fetal cells isolated from maternal blood using single-chromosome dual-probe FISH analysis. Clin. Genet. 2012, 82, 131–139.
  25. Petit, C.; Fleurentin, A.; Fontaine, B.; Miton, A.; Lemarie, P.; Philippe, C.; Jonveaux, P. Use of the Kleihauer test to detect fetal erythroblasts in the maternal circulation. Prenat. Diagn. 2001, 21, 106–111.
  26. D’Souza, E.; Ghosh, K.; Colah, R. A comparison of the choice of monoclonal antibodies for recovery of fetal cells from maternal blood using FACS for noninvasive prenatal diagnosis of hemoglobinopathies. Cytom. Part B Clin. Cytom. 2008, 76, 175–180.
  27. Nemescu, D.; Constantinescu, D.; Gorduza, V.; Carauleanu, A.; Caba, L.; Navolan, D.B. Comparison between paramagnetic and CD71 magnetic actived cell sorting of fetal nucleated red blood cells from the maternal blood. J. Clin. Lab. Anal. 2020, 34, e23420.
  28. Zimmermann, S.; Hollmann, C.; Stachelhaus, S.A. Unique monoclonal antibodies specifically bind surface structures on human fetal erythroid blood cells. Exp. Cell Res. 2013, 319, 2700–2707.
  29. Wei, X.; Ao, Z.; Cheng, L.; He, Z.; Huang, Q.; Cai, B.; Rao, L.; Meng, Q.; Wang, Z.; Sun, Y.; et al. Highly sensitive and rapid isolation of fetal nucleated red blood cells with microbead-based selective sedimentation for non-invasive prenatal diagnostics. Nanotechnology 2018, 29, 434001.
  30. Johnson, P.; Molloy, C. Localization in Human Term Placental Bed and Amniochorion of Cells Bearing Trophoblast Antigens Identified by Monoclonal Antibodies. Am. J. Reprod. Immunol. 1983, 4, 33–37.
  31. Cacheux, V.; Milesi-Fluet, C.; Tachdjian, G.; Druart, L.; Bruch, J.F.; Hsi, B.L.; Uzan, S.; Nessmann, C. Detection of 47, XYY trophoblast fetal cells in maternal blood by fluorescence in situ hybridization after using immunomagnetic lymphocyte depletion and flow cytometry sorting. Fetal Diagn. Ther. 1992, 7, 190–194.
  32. Pötgens, A.J.; Schmitz, U.; Kaufmann, P.; Frank, H.-G. Monoclonal Antibody CD133–2 (AC141) Against Hematopoietic Stem Cell Antigen CD133 Shows Crossreactivity with Cytokeratin 18. J. Histochem. Cytochem. 2002, 50, 1131–1134.
  33. Kilpivaara, O.; Dhanjal, S.; Hulte’n, M.A. Cytotrophoblasts-specific antibodies for identification of fetal 76 cells in maternal blood. In Early Prenatal Diagnosis, Fetal Cells and DNA in the Mother; Karolinum Press: Prague, Czech Republic, 2002; pp. 34–39.
  34. Kølvraa, S.; Singh, R.; Normand, E.A.; Qdaisat, S.; van den Veyver, I.B.; Jackson, L.; Hatt, L.; Schelde, P.; Uldbjerg, N.; Vestergaard, E.M.; et al. Genome-wide copy number analysis on DNA from fetal cells isolated from the blood of pregnant women. Prenat. Diagn. 2016, 36, 1127–1134.
  35. Guetta, E.; Gutstein-Abo, L.; Barkai, G. Trophoblasts isolated from the maternal circulation: In vitro expansion and potential application in non-invasive prenatal diagnosis. J. Histochem. Cytochem. 2005, 53, 337–339.
  36. van Wijk, I.J.; Griffioen, S.; Tjoa, M.L.; Mulders, M.A.; van Vugt, J.M.; Loke, Y.W.; Oudejans, C.B. HLA-G expression in trophoblast cells circulating in maternal peripheral blood during early pregnancy. Am. J. Obstet. Gynecol. 2001, 184, 991–997.
  37. Hatt, L.; Brinch, M.; Singh, R.; Møller, K.; Lauridsen, R.H.; Uldbjerg, N.; Huppertz, B.; Christensen, B.; Kølvraa, S. Characterization of fetal cells from the maternal circulation by microarray gene expression analysis—Could the extravillos trophoblasts be a target for future cell-based non-invasive prenatal diagnosis. Fetal Diagn. Ther. 2014, 35, 218–227.
  38. Sargent, I.L.; Choo, Y.S.; Redman, C.W. Isolating and analyzing fetal leukocytes in maternal blood. Ann. N. Y. Acad. Sci. 1994, 731, 147–153.
  39. Benirschke, K. Anatomical Relationship between Fetus and Mother. Ann. N. Y. Acad. Sci. 1994, 731, 9–20.
  40. Purwosunu, Y.; Sekizawa, A.; Koide, K.; Okazaki, S.; Farina, A.; Okai, T. Clinical potential for noninvasive prenatal diagnosis through detection of fetal cells in maternal blood. Taiwan. J. Obstet. Gynecol. 2006, 45, 10–20.
  41. Mouawia, H.; Saker, A.; Jais, J.-P.; Benachi, A.; Bussières, L.; Lacour, B.; Bonnefont, J.-P.; Frydman, R.; Simpson, J.L.; Paterlini-Brechot, P. Circulating trophoblastic cells provide genetic diagnosis in 63 fetuses at risk for cystic fibrosis or spinal muscular atrophy. Reprod. Biomed. Online 2012, 25, 508–520.
  42. Gänshirt, D.; Garritsen, H.; Miny, P.; Holzgreve, W. Fetal cells in maternal circulation throughout gestation. Lancet 1994, 343, 1038–1039.
  43. Kavanagh, D.; Kersaudy-Kerhoas, M.; Dhariwal, R.; Desmulliez, M. Current and emerging techniques of fetal cell separation from maternal blood. J. Chromatogr. B 2010, 878, 1905–1911.
  44. Mohamed, H.; Turner, J.N.; Caggana, M. Biochip for separating fetal cells from maternal circulation. J. Chromatogr. A 2007, 1162, 187–192.
  45. Huang, R.; Barber, T.A.; Schmidt, M.A.; Tompkins, R.G.; Toner, M.; Bianchi, D.W.; Kapur, R.; Flejter, W.L. A microfluidics approach for the isolation of nucleated red blood cells (NRBCs) from the peripheral blood of pregnant women. Prenat. Diagn. 2008, 28, 892–899.
  46. Autebert, J.; Coudert, B.; Bidard, F.-C.; Pierga, J.-Y.; Descroix, S.; Malaquin, L.; Viovy, J.-L. Microfluidic: An innovative tool for efficient cell sorting. Methods 2012, 57, 297–307.
  47. Wang, Z.; Cheng, L.; Wei, X.; Cai, B.; Sun, Y.; Zhang, Y.; Liao, L.; Zhao, X.-Z. High-throughput isolation of fetal nucleated red blood cells by multifunctional microsphere-assisted inertial microfluidics. Biomed. Microdevices 2020, 22, 75.
  48. Huang, C.-E.; Ma, G.-C.; Jou, H.-J.; Lin, W.-H.; Lee, D.-J.; Lin, Y.-S.; Ginsberg, N.A.; Chen, H.-F.; Chang, F.M.-C.; Chen, M. Noninvasive prenatal diagnosis of fetal aneuploidy by circulating fetal nucleated red blood cells and extravillous trophoblasts using silicon-based nanostructured microfluidics. Mol. Cytogenet. 2017, 10, 44.
  49. Ma, G.-C.; Lin, W.-H.; Huang, C.-E.; Chang, T.-Y.; Liu, J.-Y.; Yang, Y.-J.; Lee, M.-H.; Wu, W.-J.; Chang, Y.-S.; Chen, M. A Silicon-based Coral-like Nanostructured Microfluidics to Isolate Rare Cells in Human Circulation: Validation by SK-BR-3 Cancer Cell Line and Its Utility in Circulating Fetal Nucleated Red Blood Cells. Micromachines 2019, 10, 132.
  50. Gur, O.; Chang, C.L.; Jain, R.; Zhong, Y.; Savran, C.A. High-purity isolation of rare single cells from blood using a tiered microchip system. PLoS ONE 2020, 15, e0229949.
  51. Sun, Y.; Cai, B.; Wei, X.; Wang, Z.; Rao, L.; Meng, Q.-F.; Liao, Q.; Liu, W.; Guo, S.; Zhao, X. A valve-based microfluidic device for on-chip single cell treatments. Electrophoresis 2018, 40, 961–968.
  52. Voullaire, L.; Ioannou, P.; Nouri, S.; Williamson, R. Fetal nucleated red blood cells from CVS washings: An aid to development of first trimester non-invasive prenatal diagnosis. Prenat. Diagn. 2001, 21, 827–834.
  53. Bianchi, D.W.; Flint, A.F.; Pizzimenti, M.F.; Knoll, J.H.; Latt, S.A. Isolation of fetal DNA from nucleated erythrocytes in maternal blood. Proc. Natl. Acad. Sci. USA 1990, 87, 3279–3283.
  54. Twu, Y.C.; Chen, C.P.; Hsieh, C.Y.; Tzeng, C.H.; Sun, C.F.; Wang, S.H.; Chang, M.S.; Yu, L.C. I branching formation in erythroid differentiation is regulated by trascription factor C/EBPalpha. Blood 2007, 110, 4526–4534.
  55. Sitar, G.; Brambati, B.; Baldi, M.; Montanari, L.; Vincitorio, M.; Tului, L.; Forabosco, A.; Ascari, E. The use of non-physiological conditions to isolate fetal cells from maternal blood. Exp. Cell Res. 2005, 302, 153–161.
  56. Calabrese, G.; Fantasia, D.; Alfonsi, M.; Morizio, E.; Celentano, C.; Franchi, P.G.; Sabbatinelli, G.; Palka, C.; Benn, P.; Sitar, G. Aneuploidy screening using circulating fetal cells in maternal blood by dual-probe FISH protocol: A prospective feasibility study on a series of 172 pregnant women. Mol. Genet. Genom. Med. 2016, 4, 634–640.
  57. Guanciali Franchi, P.; Palka, C.; Morizio, E.; Sabbatinelli, G.; Alfonsi, M.; Fantasia, D.; Sitar, G.; Benn, P.; Calabrese, G. Sequential combined test, second trimester maternal serum markers, and circulating fetal cells to select women for invasive prenatal diagnosis. PLoS ONE 2017, 12, e0189235.
  58. Von Koskull, H.; Gahmberg, N. Fetal erythroblasts from maternal blood identified with 2,3-bisphosphoglycerate (BPG) and in situ hybridization (ISH) using Y-specific probes. Prenat. Diagn. 1995, 15, 149–154.
  59. Wachi, T.; Katagawa, M. Studies on preliminary concentration methods for recovery of fetal nucleated red blood cells in maternal blood. Congenit. Anom. 2004, 44, 196–203.
  60. Takabayashi, H.; Kuwabara, S.; Ukita, T.; Ikawa, K.; Yamafuji, K.; Igaras, T. Development of non-invasive fetal DNA diagnosis from maternal blood. Prenat. Diagn. 1995, 15, 74–77.
  61. Wachtel, S.S.; Sammons, D.; Manley, M.; Wachtel, G.; Twitty, G.; Utermohlen, J.; Phillips, O.P.; Shulman, L.P.; Taron, D.J.; Müller, U.R.; et al. Fetal cells in maternal blood: Recovery by charge flow separation. Hum. Genet. 1996, 98, 162–166.
  62. Byeon, Y.; Ki, C.S.; Han, K.H. Isolation of nucleated red blood cells in maternal blood for Non-invasive prenatal diagnosis. Biomed Microdevices 2015, 17, 118.
  63. Boyer, S.H.; Noyes, A.N.; Boyer, M.L. Enrichment of erythro-cytes of fetal origin from adult–fetal blood mixtures via selective hemolysis of adult blood cells: An aid to antenatal diagnosis of hemoglobinopathies. Blood 1976, 47, 883–897.
  64. Kitagawa, M.; Sugiura, K.; Omi, H.; Akiyama, Y.; Kanayama, K.; Shinya, M.; Tanaka, T.; Yura, H.; Sago, H. New techniques using galactose-specific lectin for isolation of fetal cells from maternal blood. Prenat. Diagn. 2002, 22, 17–21.
  65. Henkelman, S.; Rakhorst, G.; van der Mei, H.C.; Busscher, H.J. Use of hydroxyethyl starch for inducing red blood cell aggregation. Clin. Hemorheol. Microcirc. 2012, 52, 27–35.
  66. Vona, G.; Beroud, C.; Benachi, A.; Quenette, A.; Bonnefont, J.-P.; Romana, S.P.; Dumez, Y.; Lacour, B.; Paterlini-Bréchot, P. Enrichment, Immunomorphological, and Genetic Characterization of Fetal Cells Circulating in Maternal Blood. Am. J. Pathol. 2002, 160, 51–58.
  67. Béroud, C.; Karliova, M.; Bonnefont, J.; Benachi, A.; Munnich, A.; Dumez, Y.; Lacour, B.; Paterlini-Bréchot, P. Prenatal diagnosis of spinal muscular atrophy by genetic analysis of circulating fetal cells. Lancet 2003, 361, 1013–1014.
  68. Saker, A.; Benachi, A.; Bonnefont, J.P.; Munnich, A.; Dumez, Y.; Lacour, B.; Paterlini-Brechot, P. Genetic characterisation of circulating fetal cells allows non-invasive prenatal diagnosis of cystic fibrosis. Prenat. Diagn. 2006, 26, 906–916.
  69. Bolnick, J.M.; Kilburn, B.A.; Bajpayee, S.; Reddy, N.; Jeelani, R.; Crone, B.; Simmerman, N.; Singh, M.; Diamond, M.; Armant, D.R. Trophoblast retrieval and isolation from the cervix (TRIC) for noninvasive prenatal screening at 5 to 20 weeks of gestation. Fertil. Steril. 2014, 102, 135–142.e6.
  70. Fritz, R.; Kohan-Ghadr, H.R.; Sacher, A.; Bolnick, A.D.; Kilburn, B.A.; Bolnick, J.M.; Diamond, M.P.; Drewlo, S.; Armant, D.R. Trophoblast retrieval and isolation from the cervix (TRIC) is unaffected by early gestational age or maternal obesity. Prenat. Diagn. 2015, 35, 1218–1222.
  71. Hall, J.M.; Adams, S.; Williams, S.; Rehse, M.A.; Layton, T.J.; Molesh, D.A. Purification of fetal cells from maternal blood using an avidin-biotin immunoaffinity column. Ann. N. Y. Acad. Sci. 1994, 731, 115–127.
  72. Hultén, M.A.; Dhanjal, S. A novel assay for rapid and simple non-invasive prenatal diagnosis of genetic anomalies. In Early Prenatal Diagnosis, Fetal Cells and DNA in the Mother; Karolinum Press: Prague, Czech Republic, 2002; pp. 59–71.
  73. Evans, M.I.; Sharp, M.; Tepperberg, J.; Kilpatrick, M.W.; Tsipouras, P.; Tafas, T. Automated Microscopy of Amniotic Fluid Cells: Detection of FISH Signals Using the FastFISH® Imaging System. Fetal Diagn. Ther. 2006, 21, 523–527.
Video Production Service