Stem cells have incredible potential for regenerative medicine, but getting hold of them in large enough numbers can be tricky. Amniotic fluid may be a plentiful source, and now scientists from Lund University in Sweden have developed a method and device that can collect the fluid during delivery of a baby by caesarean section, to safely harvest large amounts of stem cells.

With the ability to replicate into other cells in the body, stem cells are valuable as a potential starting point for treating a wide range of illnesses, such as cardiovascular disease, diabetes, cancer and Alzheimer's, and potentially restoring impaired hearing or vision. The problem is that current methods of extracting them are either invasive and painful – as is the case from bone marrow – ethically controversial when sourced from human embryos, or don't have a very high yield, such as from umbilical cord blood.

Amniotic fluid, the nutrient-rich liquid that surrounds and protects a developing fetus, may be one of the most promising sources of stem cells. It provides a substantial amount at once and, when collected during a planned caesarian section, it's no more invasive than the birthing procedure already is.

The Lund team developed a new device and method for collecting the fluid and harvesting the stem cells from it, specifically Mesenchymal Stem Cells (MSCs). The device, which is 3D printed out of bio-inert plastics, forms a seal with the fetal cavity, allowing doctors to gently and safely extract the fluid that is usually regarded as medical waste. The liquid is then run through a gauze filter, a 100-micron cell strainer, and finally a centrifuge to isolate the MSCs, which are then grown in culture.

"We showed that using our device, we can collect up to a liter of amniotic fluid at full-term caesarean deliveries," says Andreas Herbst, corresponding author of the study. "The collection added on average 90 seconds to the operation, and was safe for both mother and child."

MSCs can differentiate into a wide variety of cell types, but the researchers took them a step further. They found that the MSCs can then be converted into a state similar to that of embryonic stem cells, which means they can potentially become any cell type in the body.

"The combination of this novel device and the coupled cellular selection and cultivation methods could be transformative for the stem cell field, as large quantities of newborn-MSC's can be provided by utilizing this waste material," says Marcus Larsson, corresponding author of the study. "The safety standards we adhere to are also a central component for gaining clinical acceptance. The obvious next step would be to evaluate these cells further in the laboratory and, if successful, in disease models."

The research was published in the journal Stem Cell Research & Therapy.

The harvesting technique is demonstrated in the following animation.