The group also says these engineered tissues will be ideal as an in vitro skin equivalent for cosmetics, pharmaceutical and chemical substance testing.
The project is focused on creating an artificial, three-layered “perfused skin model.”
This work has led to what the group says is a means of cultivating a full-thickness skin model – and at greater layer thicknesses than was previously possible.
Vascularization is the key to the process, and it’s one of the most challenging issues in the development of soft tissue. It’s a required process to supply cells with nutrition within the multiple layers of tissue such as artificial skin. At this juncture, it’s only been possible to build the upper layers of the skin – the epidermis and dermis. Those layers have a total thickness of up to 200 µm on the outside the human body, but a complete skin system includes subcutaneous tissue, and that layer may be up to several millimeters thick.
ArtiVasc 3D says their goal is “enabling significantly more complex tissues to be cultivated in vitro by developing artificial blood vessels.”
To make it happen, the scientists at ILT say they’ve combined the freeform methods of inkjet printing with stereolithography, and using those processes, they’ve achieved a very fine resolution for constructing branched, porous blood vessels with layer thicknesses of about 20µm. Using mathematical simulations, they developed the data needed for the construction of these branched structures, and that means the constructs will allow uniform blood supply.
An acrylate-based synthetic polymer, developed specifically for the project, allows the team to construct optimized vessels with a pore diameter in the range of hundreds of microns, and as compared to conventional methods, the ArtiVasc 3D method is the first to arrive at branched and biocompatible vessels in this size.
“A toolbox has been developed that can respond flexibly to diverse materials, shapes and sizes. These results can be viewed as a precursor to a fully automated process chain for the production of artificial blood vessels, and which can also be integrated into existing lines,”
they say in their concluding report. “Another highlight of the project is the successful breeding of adipose tissue in a novel bioreactor. The combination of the fatty tissue with an existing skin model allowed the production of a full-thickness skin model which has a thickness of up to 12mm.”
And ArtiVasc 3D says the project may well prove to be the foundation for more bold feats of three-dimensional tissue engineering such as the construction of larger structures, perhaps even whole organs.
The researchers are prepared to present their findings at Fraunhofer ILT on October 28-29, 2015, in Aachen, Germany.
What do you think of this initiative which promises a solution to the toughest problems when it comes to 3D printing human tissues and skin? Let us know in the ArtiVasc 3D forum thread on 3DPB.com.