Intraoperative bioprinting for improved facial skin reconstruction
Researchers have intraoperatively bioprinted full-thickness skin directly onto mouse facial wounds. The repaired skin healed successfully and could facilitate hair growth, which could enable better matching of patients’ original facial features.
In a recent study, researchers at Penn State University (PA, USA) were the first to bioprint facial skin directly onto facial wound sites during surgery. The precisely dropped bioinks successfully achieved full-thickness skin capable of closing wounds with a possibility for hair growth. The group hopes the technology could pave the way for safer and better-matched facial skin grafts.
The sensitivity of cosmetic outcomes and the presence of vital structures around the head and neck make reconstructive facial surgery particularly challenging. Currently, skin grafts carry a number of possible risks, including scarring, poor restoration of facial features, alopecia and complications at the donor site. Researchers are now looking to 3D bioprinted skin as an alternative to these autologous grafts.
Skin is made up of three layers: the epidermis, which is the visible outermost layer; the dermis, a middle layer that includes sweat glands and hair follicles; and the hypodermis, the innermost layer consisting of fat and connective tissue to support the skin over the skull. The hypodermis also hosts downgrowths, which are the precursors to hair follicles.
The research group created a bioink containing adipose (fat)-derived extracellular matrix and stem cells. Using a system of bioprinting valves, they precisely ejected droplets of the bioink directly onto the wound site during surgery to create a two-layered system consisting of the hypodermis and dermis. This is the first time that skin has been bioprinted during surgery, rather than beforehand.
After two weeks, the mice had grown an outermost epidermis layer at the wound site, demonstrating successful full-thickness skin reconstruction. Their wounds were also almost entirely healed. Excitingly, the researchers also found downgrowths in the hypodermis, indicating the possibility for future hair growth.
“In our experiments, the fat cells may have altered the extracellular matrix to be more supportive for downgrowth formation,” explains lead researcher from the group, Ibrahim Ozbolat. “We are working to advance this, to mature the hair follicles with controlled density, directionality and growth.”
The authors hope to advance their bioprinting technology to enable better matching of facial reconstructions to patients’ native features, opening the door to a range of applications in the surgical and dermatological fields.