Would you wear bio printed skin?

By Claire Lucille Padilla

​In the dynamic landscape of medical advancements, one topic is particularly thrilling—the revolutionary field of bioprinting. Bioprinting is emerging as a promising method for producing skin substitutes with the potential to revolutionize wound healing and tissue regeneration. ​

 With around 500,000 patients being treated annually in the United States for burn injuries and an estimated 11 million burn injuries occurring globally each year, bioprinting is more important than ever before. Bioprinting will serve to aid those with damage penetrating through many definitions of their skin as there are limitations to current treatment methods such as autologous skin grafting. Autologous skin grafting is a popular treatment of burning where healthy skin is taken from the patient and translated to replace burned areas. However, with such a substantial cost associated with it, this healing method is extremely inaccessible. In attempts to reduce the costs and the invasiveness of healing surgical procedures, biomedical researchers are exploring bioprinted skin. Bioprinted skin is not solely limited to burn wounds, but can benefit several other severe injuries including venous ulcers,  pressure ulcers (bedsores), and diabetic ulcers.

A recent study published October 4th 2023 in Science Translational Medicine explores the use of bioprinting to create skin substitutes that mimic the structural organization of human skin. The researchers were able to successfully bioprint a trilayer skin construct consisting of the epidermis, dermis, and hypodermis using six primary human skin cell types:keratinocytes, melanocytes, dermal fibroblasts, follicle-derived papilla cells, and pre-adipocytes. The efficacy of the bioprinted skin of the multiple cell types’s skin regeneration and development of ridges in the outermost layer of the skin in full-thickness wounds. To test the bioprinted skin, the researchers ran two distinct animal studies, one utilizing mice and the other pigs. 

The study aimed to evaluate the efficacy of bioprinted skin in wound treatment using mouse and pig models. In the mouse study, three groups received different treatments: bioprinted skin, a supportive control hydrogel, and untreated wounds. Beyond application, the researchers assessed the integration of bioprinted skin by examining blood vessel formation, collagen alignment, outer skin layer development, and maturation alongside secondary factors like wound closure time and pigmentation. Six groups underwent diverse treatments in the pig study, highlighting the distinctions between 3D-printed bioprinted skin with donor cells (autograft/allograft) and traditional skin grafting methods. This comprehensive approach provides insights into bioprinted skin's effectiveness and compatibility compared to conventional treatments, offering a nuanced understanding of its role in skin regeneration.

How did the scientists go about fixing these pigs and mice? The scientists used an integrated tissue and organ printer to make skin. They used an integrated tissue and organ printer to make the skin, testing it on both mice and pigs. The researchers tested the skin’s health, by using tests like the LIVE/DEAD test and took pictures of the skin. They monitored the progress of each of the mice and pig groups and photographed their improvement and healing over time through a program called ImageJ. The researchers also looked at the skin under microscopes and used different cell specific stains to see how the skin was growing and how its structure formed. They also used programs to analyze the collagen in the skin and made sure the blood vessels in the new cells were forming and functioning properly.
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The researchers successfully integrated bioprinted skin into wounds in mice, with blood vessels growing into the new skin. The increased blood vessels resulted in a healthy collagen structure. The bioprinted skin also formed an epidermis similar to human skin, which is crucial for function and appearance. These improvements underscore the transformative potential of bioprinting technology in enhancing the natural regenerative processes of the body. The bioprinted skin wounds closed faster in mice without causing excessive skin contraction. In pig studies, the skin grafts improved wound closure and regeneration due to the genes associated with wound healing. The researchers observed increased capillaries in mouse wounds treated with bioprinted skin, suggesting improved blood vessel growth, however no hair follicle growth. Gene analysis in pigs showed gene changes related to wound healing and collagen production. They found that integrating human dermal fibroblasts( skin connective tissue) played a role in making the new epidermis more human-like. This research is expected to continue refining bioprinting techniques and exploring their applications in various skin injuries and wound types. As bioprinting technology advances, we can anticipate more breakthroughs in wound healing and tissue regeneration, bringing hope and relief to patients suffering from various skin injuries.