Current and emerging techniques of fetal cell separation from maternal blood

Intense research has been carried out in recent years into methods that aim to harvest fetal genetic material from maternal blood as substitutes to amniocentesis and chorionic villus sampling. Just over 30 years have past since the first fetal cells were separated from maternal blood using flow cytometry highlighting the prospect of non-invasive prenatal diagnosis of fetal abnormalities. The aim of this review paper is to describe the most commonly used cell separation methods with emphasis on the isolation of fetal cells from maternal blood. The most significant breakthroughs and advances in fetal cell separation are reviewed and critically analyzed. Although much has been accomplished using well established techniques, a rapid and inexpensive method to separate fetal cells with great accuracy, sensitivity and efficiency to maximize cell yield is still required. In the past decade MEMS (Micro Electro Mechanical Systems) technologies have enabled the miniaturization of many biological and medical laboratory processes. Lab-on-chip systems have been developed and encompass many modules capable of processing different biological samples. Such chips contain various integrated components such as separation channels, micropumps, mixers, reaction and detection chambers. This article will also explore new emerging MEMS based separation strategies, which hope to overcome the current limitations in fetal cell separation.