Embryos get Better Start with IVF on a Chip

CAN conception, the most intimate of human experiences, be automated? Teruo Fujii of the University of Tokyo in Japan and his colleagues are building a microfluidic chip to nurture the first stages of pregnancy. They hope, eventually, to create a fully automated artificial uterus in which egg and sperm are fed in at one end and an early embryo comes out the other, ready for implanting in a real mother. They say using such a device could improve the success rate of IVF.

“While there have been many advances in the production of in vitro embryos, these embryos are still sub-optimal [compared] to their in vivo counterparts,” says Matt Wheeler of the University of Illinois in Urbana-Champaign who is also working on automated IVF systems. One reason for this is that during IVF, eggs or embryos are often moved or washed with culture fluid, causing changes in temperature and pH, he says.

To tackle these problems, Fujii’s team has created a lab on a chip that is 2 millimeters across and 0.5 millimeters high, in which up to 20 eggs can be fertilized and then grown until they are ready for implantation. Endometrial cells, which line real wombs, are also grown in the device, so that the chemicals they produce can reach the embryos and help them grow.

“We are providing the embryos with a much more comfortable environment, mimicking what happens in the body,” Fujii says.

Experiments in mice suggest that the chip is more successful than traditional IVF at producing embryos that will grow into healthy fetuses. Of 50 fertilized eggs grown on the chip, 30 developed into early embryos, compared to 26 out of 50 fertilized eggs grown through microdrop IVF. Here a drop of mineral oil is used to cover the fertilized egg and a small volume of culture fluid to stop the egg drying out.

In a separate experiment, Fujii’s team implanted embryos grown on the chip into mice and found that 44 per cent of them developed into healthy fetuses, compared to 40 per cent of those grown in microdrops. “It’s not just about more embryos surviving to be implanted, they also seem to be doing better once they are implanted,” says Wheeler.

The results were presented at a meeting in Lyon, France, earlier this month. Fujii’s team has approval to test the device on human embryos and will do so later this year.

For now the sperm and eggs are still prepared for fertilization manually but the researchers are working towards automating those steps too. Wheeler’s team has already automated them, but has not compared his chip-grown embryos with ones produced by conventional IVF, nor grown endometrial cells on a chip. He suggests that combining his approach with Fujii’s might produce even better results.

The chip could also be used for growing genetically modified animals, stem cells and cloned embryos, he adds.