Isolation of foetal cells from the blood of pregnant women

Background
Many pregnant women wishes to have their foetus tested for genetic defects as e.g. Down's Syndrome so they have the possibility of having the pregnancy terminated. However, the methods used for prenatal genetic diagnostics today i.e. amniocentesis and chorionic villus sampling are invasive procedures that carry a substantial risk of pregnancy loss (0.5-1%) or even harming the foetus [1]. Therefor are new diagnostic methods desired that will allow prenatal diagnosis without the risk of harming the foetus. It has been reported that a small number of cell of foetal origin are present in mothers blood (about 1:106-107) [2]. The aim of the project is to develop a simple and cheap method to isolate these few foetus cells from a blood sample form the mother.
The system
A new method for isolating foetal cells form a blood sample from the mother is being developed at the Microelectronic Centre in collaboration with Rigshospitalet. In this methods antibodies against the foetal cells are applied. In one end these antibodies are attached to small paramagnetic particles so when they are mixed with the blood sample the foetal cells becomes paramagnetic. The foetal cells are separated from the mother cells in a channel system on a silicon chip. The channel system has two outlets and the non-magnetic mother cells are led out of one outlet whereas the paramagnetic foetal cells are led to the other outlet using magnets. This system should make it possible to isolate foetal cells faster and cheaper and the system can be made disposable which eliminate the risk of cross contamination from one sample to the next.