Chronic wounds are deep and can be difficult to repair. The wound may collapse by itself when the area of the injury heals first. This can result in scar tissue and diminished skin function over time.
In APL Bioengineering APL Bioengineering, published by AIP Publishing, researchers from the University of Birmingham and University of Huddersfield created a method to print skin-like substitutes. The material could be used to aid in healing of chronic wounds.
This technique simulates three layers of skin, the hypodermis (or the fatty layer) the dermis, and the epidermis.
In essence there are three types of cells. They all grow at different rates. It isn’t easy to meet the needs of each layer of tri-layered structures.
Alan Smith, Author
To address this issue scientists utilized suspended layer additive manufacturing (SLAM). To support the skin equivalent, they developed a gel-like material. They then twisted and altered the structure of the gel, creating the bed of particles that could support an additional phase.
During printing, the skin layers are put in the support gel which is what holds everything in place. After printing the team washed off the support material and left behind the skin-like layer.
Researchers discovered that if a needle was moved through the support gel it would heal itself faster than other similar techniques. This allows printing intricate skin structures at a higher resolution than other methods.
The authors tried out the skin substitute using the pig’s tissue as a model and then printed a skin replacement to fill in the hole. After culturing the model system for 14 days, they observed indications of wound healing.
“We utilized a stain that allowed us to quantify the level of integration we achieved between the tissue and the original material,” said author Liam Grover. “We were able to demonstrate some integration even after a short period of time.”
The team cannot assess chronic wound healing using the skin substitute since the process takes longer than the model they used, which was only 14-21 days. Their next step is to test longer-lasting models for chronic deep wounds. The ultimate goal is to heal human skin and reduce scarring in all types of patient situations.
Moakes R.J.A., and Al. (2021). A suspended layer additive manufacturing technique for the bioprinting tri-layered skin substitutes. APL Bioengineering. doi.org/10.1063/5.0061361.
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