(Credit: Helena Paffen via CC)
3D printed skin is used for grafting as well as toxicology and chemical testing, but currently lacks complex features such as pigmentation or hair follicles. However, by controlling the distribution of melanin-producing skin cells on a biomimetic tissue substrate, human-like skin pigmentation can be produced. The work is described in the journal Biofabrication.
"3D bioprinting is an excellent platform for the precise deposition of biomaterials and living cells to make biomimetic skin, in large volumes with great repeatability,” said lead author Wei Long Ng, from Singapore’s Nanyang Technological University.
“However, non-uniform skin pigmentation is often seen, and this remains a huge challenge to be solved.”
The research team featured scientists and engineers from the Singapore Institute of Manufacturing Technology (SIMTech) as well as Nanyang’s Singapore Centre for 3D Printing (SC3DP). Three different types of skin cells - keratinocytes, melanocytes, and fibroblasts – were used to create the pigmented skin, in what is described as a two-step ‘drop on demand’ bioprinting method.
"The two-step bioprinting strategy involves the fabrication of hierarchical porous collagen-based structures (that closely resembles the skin's dermal region), and deposition of epidermal cells such as keratinocytes and melanocytes at pre-defined positions on top of the biomimetic dermal skin constructs, to create 3D in-vitro pigmented human skin constructs,” said Wei Long.
"When we compared the 3D bioprinted skin constructs to those made using a manual-casting method, we found two distinct differences between the two fabrication approaches - the cell distribution on top of the dermal regions, and the microstructures within the dermal regions. The two-step bioprinting strategy enables the standardised distribution of printed cells in a highly-controlled way, as compared to the manual casting approach."
According to the team, the bioprinting technique has the additional benefit of allowing pore size to be manipulated, something that is much more challenging when casting skin manually.
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