The artificial lung in the microfluidic chip

In cooperation with the Organs-on-Chip Technologies Lab headed by Prof. Olivier Guenat, from the University of Bern, Torson Injex AG was able to participate in the production of a complex microfluidic chip. The challenges were manifold, but the result was impressive. Precise micro injection molding to produce the smallest structures and the processing of sophisticated materials were required. The result is a microfluidic chip that enables the cultivation of human cells on a biological membrane. This showcase not only demonstrates progress in medical research but also emphasizes the innovative strength and future viability of cooperation between industry and research institutions.

The Challenge

In April 2021, Tobias Weber from the Organs-on-Chip Technologies Lab approached Torson Injex to ask whether a multilayer microfluidic chip could be made from COC. In addition, different surface structures had to be applied. Different functions were required depending on the area. In the central areas, a high level of transparency should enable the cultivated cells to be observed. In the fluid channels, a smooth but not polished surface was required and in the outer areas, a deliberately rough texture was needed to facilitate the joining of the individual chip layers.

It should also be possible to pump air and liquids on the chip in a targeted manner. This requires some of the smallest channels with dimensions of 100x500 micrometers. The material to be used, TOPAS® COC from Polyplastics, was also a challenge. Thanks to its outstanding properties in terms of transparency, purity and impermeability, it is the ideal material for microfluidic applications. However, processing it in injection molding is not trivial and required some fine-tuning.

The Results

Less than four weeks after the three components were ordered, the first injection-molded samples in the desired COC material were shipped. Thanks to Torson Injex's in-house toolmaking department, even the most demanding requirements could be implemented in the shortest possible time and according to customer specifications. And all within a budget of less than CHF 20'000. The subsequent design iterations were also successfully implemented within a very short space of time.

The Chip in Action

At the University of Bern, the three layers are bonded together in a final process step to form the final chip. The result is impressive.

The chip contains structures for producing a biological membrane. A gold grid and a thin hydrogel form the basis on which cells from lung tissue are cultivated. Integrated fluidic structures continuously supply the cells with nutrients. The chip also simulates the rhythmic stretching of breathing, which stimulates the growth of alveolar cells.

The chip is connected to pressure regulators to precisely control the pneumatic valves. The chips with the cells on the membrane are then stored in an incubator at 100% humidity and 37°C, which are optimal growth conditions for the cells. The cells are then placed in the incubator, stretched by the pumps and, depending on the experiment, drugs can be tested on the cells or diseases can be induced to study their progression outside of a living organism. Thanks to the transparency of the chip, it is also possible to observe the cells with a microscope through the chip and to study their development and behavior in more detail.

Conclusion

The project was a complete success for everyone involved. Torson Injex was able to demonstrate its in-house expertise and gain valuable experience in the field of microfluidics. At the University of Bern, the microfluidic chip opened new doors for organs-on-chip research and showed how innovative technologies can shape the interface between research and industry. In the meantime, further projects in this field have already been implemented.