Advancements in Skin Regeneration: Swedish Researchers' Breakthrough with 3D Bioprinting
I. The Criticality of Skin Regeneration in Severe Burns and Trauma
In the realm of treating severe burns and trauma, skin regeneration assumes a life - and - death significance. Conventionally, extensive burns are managed through the transplantation of a thin epidermal layer, the outermost stratum of the skin, sourced from other body regions. However, this approach has significant drawbacks. Not only does it lead to the formation of large scars, but it also fails to restore the skin to its original functional state. A skin can only be considered normal and viable when the dermis, the layer beneath the epidermis housing blood vessels and nerves, is regenerated.
II. Swedish Researchers' Pioneering Work
A. Development of 3D Bioprinting Techniques
Swedish researchers have made strides that potentially bring the medical community closer to achieving living skin regeneration. They have developed two distinct 3D bioprinting techniques aimed at artificially generating thick, vascularized skin, i.e., skin containing blood vessels. One technique focuses on creating cell - packed skin, while the other enables the formation of arbitrarily shaped blood vessels within the tissue. These two methods, despite their different approaches to the same challenge, are detailed in two studies published in the journal Advanced Healthcare Materials.
B. The Concept Behind the Approach
Johan Junker, an associate professor at Linköping University and a plastic surgery specialist leading this research, stated, "The dermis is an extremely complex structure. We are currently unable to grow it in the laboratory, as we don't even fully comprehend all of its components. This is why our team, along with many others, believes that transplanting the building blocks and allowing the body to construct the dermis itself might be a viable solution."
C. The μInk Bio - ink
- Composition and Creation
Junker and his team designed a bio - ink named "μInk". In this bio - ink, fibroblasts, the cells responsible for producing dermal components such as collagen, elastin, and hyaluronic acid, are cultured on the surface of small spongy gelatin grains and then encased in a hyaluronic acid gel. By leveraging a 3D printer to build up this ink in three dimensions, they were able to create a skin structure with a high - density cell distribution at will.
- Transplantation Experiment Results
In a mouse transplantation experiment, the researchers verified that living cells thrived within the tissue fragments fabricated from this ink. These cells secreted collagen and reconstructed the components of the dermis. Additionally, new blood vessels formed within the graft, indicating that the conditions for long - term tissue fixation were met.
D. The REFRESH Technology
- Function and Material
Blood vessels are of utmost importance in artificial tissue construction. Without them, regardless of the number of cultured cells in a tissue model, oxygen and nutrients cannot be uniformly distributed to all cells, and as the tissue grows, the central cells will perish. To address this, the research team developed a technology called REFRESH (Rerouting of Free - Floating Suspended Hydrogel Filaments). This technology enables the flexible construction of blood vessels in artificial tissues by printing and arranging threads of a hydrogel that is 98% water. These threads are significantly more robust than ordinary gel materials. They can maintain their shape even when tied or braided and possess shape - memory properties, allowing them to regain their original form even after being crushed.
- Vessel Formation Process
Notably, these threads can be disassembled without leaving a trace through the action of a specific enzyme. When the hydrogel threads placed in the tissue disappear, only a long, thin cavity remains in their original location. By utilizing this cavity as a flow channel equivalent to a blood vessel, a network of blood vessels can be freely formed within the artificially created tissue. By integrating this technology with the μInk - based skin creation, it becomes possible to incorporate a freely designed blood vessel network into the thick, cell - filled artificial skin, ensuring that oxygen and nutrients can reach every part of the skin.
- Complex 3D Network Construction
The researchers also successfully constructed a complex 3D network by forming the hydrogel threads into knots or braids. In the future, they aim to combine this with automation technology to efficiently distribute a blood vessel network throughout an artificial organ.
III. Challenges and Future Prospects
A. Wound Environment Uncertainties
Despite these promising developments, numerous uncertainties persist in the wound environment. Issues such as avoiding inflammation and bacterial infection need to be carefully addressed. Rigorous verification of these techniques is essential to bridge the gap between laboratory results and clinical implementation.
B. Potential Breakthrough in Regenerative Medicine
Nonetheless, these technologies hold the potential to represent a significant breakthrough in resolving long - standing issues in regenerative medicine.
This story was originally published on WIRED Japan and has been translated from Japanese.