One of the least-understood organs in the human body is the placenta. It forms only in the presence of a fetus, and the body expels it after the baby is born, so its formation and function has been very difficult to study. Learning more about it, however, is vital to understanding dangerous conditions that can threaten the lives of both mother and child. A couple of years ago, the first 3D bioprinted placenta model was created to study preeclampsia, and now researchers at TU Wien (Vienna) have 3D printed a placenta on a chip.
Organs on chips are tiny cell cultures that mimic the the structure and function of actual human organs. The TU Wien researchers created a placenta on a chip to specifically study the permeability of the placenta and gain a better understanding of how it works. One of the things they were interested in was how glucose passes from the mother to the child. This is important because studies have shown that conditions such as diabetes and high blood pressure can pass from mother to child, but it has been nearly impossible to study exactly how this happens.
“The transport of substances through biological membranes plays an important role in various areas of medicine,” said Professor Aleksandr Ovsianikov of the Institute of Materials Science and Technology at TU Wien. “These include the blood-brain barrier, ingestion of food in the stomach and intestine, and also the placenta.”
Ovsianikov and his colleagues have developed a special femtosecond laser-based 3D printing process to produce customized hydrogel membranes directly within microfluidic chips, which are then populated with placenta cells.
“Our chip consists of two areas – one represents the fetus, the other the mother,” said Denise Mandt, who worked on the project as part of her thesis. “We use a special 3D printing process to produce a partition between them – the artificial placenta membrane.”
TU Wien has spent years working on high-resolution 3D printing that uses laser beams to create 3D structures, point by point, with resolutions in the micrometer range.
“In our case it involves a hydrogel with good biocompatibility,” said Ovsianikov. “Based on the model of the natural placenta, we produce a surface with small, curved villi. The placenta cells can then colonise it, creating a barrier very similar to the natural placenta.”
The researchers can use the chip to closely monitor biological parameters such as the pressure, temperature, geometry and nutrient supply of the mini-placenta. They can also test different drugs on the 3D printed tissue, observing the progression of diseases and the rate of cure.
“This ‘organ-on-a-chip’ technology is a revolutionary approach in biomedicine, which has generated a great deal of interest in clinical diagnostics, biotechnology and pharmaceutics in recent years,” said Professor Peter Ertl, head of the cell chip research group which played a key role in the project. “The creation of human mini organs on a chip should allow the development of patient-specific therapeutic approaches, and also represents a vital method for replacing animal experiments.”
In initial testing, the placenta on a chip has behaved the way a natural placenta does, allowing small molecules to pass through while holding back larger ones. The 3D printed model will be used to study nutrient transport from the mother to the fetus.
You can read more about the study in a paper entitled “Fabrication of placental barrier structures within a microfluidic device utilizing two-photon polymerization.”
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