In the heart of Toronto, a team of researchers led by Ehsan Samiei from the University of Toronto’s Department of Mechanical and Industrial Engineering has made a significant stride in the field of tissue engineering. Their work, published in the journal Nano Select (translated to English as “Nano Choice”), focuses on creating collagen-based microgels using a technique called droplet microfluidics. This innovation could potentially revolutionize the way we approach tissue engineering and biofabrication.
Collagen, a protein abundant in our bodies, has been a staple in tissue engineering due to its biocompatibility and ability to form gels. However, its use has been limited by its poor shear-thinning behavior and lack of control over porosity during gelation. Samiei and his team have tackled these challenges head-on. “We wanted to create a granular biomaterial that could address these constraints,” Samiei explained. “Our goal was to develop a method that would allow us to control the size and shape of the microgels, making them suitable for a wider range of applications.”
The team employed a droplet microfluidic approach, a technique that involves creating droplets of a liquid within another immiscible liquid. In this case, they created droplets of fibrillar collagen and collagen-glycosaminoglycan (GAG) copolymer in a continuous oil phase. This method allowed them to produce up to 5,500 microgels per second, with sizes ranging from 40 to 170 micrometers.
The resulting microgels were found to promote the attachment and proliferation of human fibroblasts and mesenchymal stromal/stem cells. Moreover, when packed at densities exceeding 65%, these granular materials exhibited shear-thinning rheological behavior, a crucial property for injectable biomaterials and bioinks.
One of the most compelling aspects of this research is its potential impact on the energy sector. While the immediate applications are in tissue engineering and biofabrication, the principles behind this work could inspire new ways of thinking about materials design and manufacturing. For instance, the ability to control the size and shape of granular materials could lead to the development of new types of energy storage devices or more efficient catalysts.
Samiei’s team also demonstrated the potential of their microgels in a case study. They created a skin tissue model using fibroblast-containing collagen-GAG microgels, which they covered with an epithelium. After a month of air-liquid interface culture, the model exhibited immunohistochemical markers associated with intact human skin.
This research opens up new avenues for exploration in the field of tissue engineering. As Samiei puts it, “Our work is just the beginning. We’ve shown that it’s possible to create granular biomaterials with controlled properties, but there’s still much to be done in terms of optimizing these materials and exploring their potential applications.”
The implications of this research extend beyond the lab. As we continue to push the boundaries of what’s possible in tissue engineering and biofabrication, innovations like these could pave the way for new treatments and therapies, ultimately improving the quality of life for millions of people around the world.