Facial features are closely linked to our sense of identity. When an accident, disease or violent act alters a person’s face, the damage can be profound – physically, psychologically and socially. Personalized facial reconstruction is therefore in high demand. In recent years, tissue engineering of individual facial components such as bone, fat, skin and muscle has been demonstrated. However, until now, truly thick composite tissues that combine several facial layers in a single, living transplant have not been available.
A major barrier is blood supply. Large engineered grafts can only survive if they are rapidly perfused after implantation. This requires not only one or two large vessels, but a full vascular hierarchy: macrovessels that can be surgically connected to the patient’s circulation, and dense capillary networks where oxygen and nutrient exchange actually occur.
In VesselNet, we set out to create such a hierarchical vascular network within engineered tissues in vitro. Using advanced 3D bioprinting, we developed methods to fabricate customizable, multilayered composite tissues that incorporate perfusable macrovessels interconnected with fine microvascular networks, creating thick, functional grafts that could be surgically connected to host vessels and maintained by blood flow.
Within the project, we established new bioinks, support materials and bioprinting strategies that allow us to build stable, anatomically relevant tissues. We demonstrated that these vascularized constructs support tissue survival, maturation and regeneration in relevant preclinical models, and we scaled them up towards human facial defect dimensions.
The outcomes of VesselNet significantly advance the state of the art in vascularized tissue engineering. They bring personalized, full-thickness facial reconstruction closer to reality and provide powerful new tools to study tissue organization, disease mechanisms and regenerative therapies.
