Artificial Skin: Advanced Tissue Engineering for Burns, Wounds, and Future Regenerative Therapies

Background

Skin, the body’s largest organ, shields us from disease, physical trauma, and helps regulate temperature. It consists of two primary layers: the epidermis—home to keratinocytes, melanocytes, and Langerhans cells—and the dermis, rich in connective‑tissue fibers such as collagen that nourish the epidermis.

When severe damage occurs—whether from burns, diabetes‑related ulcers, or other injuries—natural healing can be too slow or inadequate. Traditional skin grafts, derived from a patient’s own skin (autografts) or from cadavers (allografts), have long been used to close wounds and correct deformities. However, autografts are limited by donor site availability, and allografts carry risks of infection and rejection, particularly when grafted to a new recipient.

In the mid‑1980s, a collaboration between cell biologists and chemical engineers sparked the field of tissue engineering, driven by a critical shortage of transplantable organs. In 1984, Harvard surgeon Joseph Vacanti discussed the scarcity of livers with MIT engineer Robert Langer. Together, they envisioned growing new tissues in the lab, beginning with skin as a proof‑of‑concept. Langer’s key insight was to build a biodegradable scaffold that would support cultured fibroblasts harvested from donated neonatal foreskins, a practice that would later become the cornerstone of artificial skin production.

Two main manufacturing strategies emerged: the mesh‑scaffolding method, where fibroblasts are grown on a polymer mesh derived from lactic and glycolic acids, and the collagen‑based method, where fibroblasts are embedded in a collagen gel extracted from young bovine tendons. In both cases, keratinocytes are later seeded to form a functional epidermal layer.

Artificial skin grafts offer clear advantages over traditional grafts: they eliminate the need for donor tissue, can be mass‑produced and cryopreserved for future use, and are rigorously screened for pathogens—such as influenza virus, hepatitis B and C, and mycoplasma—reducing infection risk. Because the engineered tissue lacks immunogenic cells, it is largely non‑reactive to the recipient’s immune system, accelerating rehabilitation and reducing scarring.

Raw Materials

Key biological components are sourced from neonatal foreskins removed during circumcision. One foreskin can yield enough cells to produce grafting material for roughly four acres of skin. Fibroblasts are isolated from the dermal layer, quarantined, and tested for viruses and other contaminants. The donor’s medical history is recorded. Once cleared, fibroblasts are cryopreserved in liquid nitrogen at –94°F (–70°C) and stored until needed. In the collagen approach, keratinocytes are similarly extracted, tested, and frozen.

For mesh scaffolding, a polymer is synthesized by polycondensation of lactic and glycolic acids, producing a biodegradable material that degrades as new tissue forms. In the collagen method, bovine collagen is extracted from the extensor tendon of young calves, mixed with an acidic nutrient medium, and stored refrigerated at 39.2°F (4°C).

Essential laboratory equipment includes glass vials, tubing, roller bottles, grafting cartridges, molds, and freezers.

The Manufacturing Process

The manufacturing workflow is deceptively straightforward, designed to coax cultured fibroblasts into behaving as if they were in their native environment, thereby promoting natural tissue formation.

Mesh Scaffolding Method

• 1. Thaw and expand fibroblasts. Cells are transferred from cryovials into roller bottles—akin to soda bottles—rotated on their sides for 3–4 weeks to ensure adequate oxygenation.
• 2. Transfer to a bioreactor. Cells are mixed with nutrient media and flowed through tubes into cassette‑like bioreactors containing the biodegradable mesh. Sterilization is achieved via e‑beam radiation. The cells adhere to the mesh, proliferate, and gradually consume the polymer as the dermal layer matures. Daily monitoring of oxygen, pH, nutrient flow, and temperature maintains optimal growth conditions.
• 3. Finalize and store. Once the dermal matrix is complete, the tissue is rinsed, cryoprotectant is added, and individual cassettes are labeled and frozen for future use.

Collagen Method

• 4. Embed fibroblasts in collagen. A small volume of cold collagen (≈12% of the total solution) is mixed with fibroblasts, dispensed into molds, and allowed to warm to room temperature, where it gels and traps the cells.
• 5. Add keratinocytes. Two weeks after collagen setting, thawed keratinocytes are seeded onto the dermal scaffold, allowed to proliferate, and then exposed to air to encourage epidermal differentiation.
• 6. Completion. The engineered skin is harvested, sterilely packaged, and stored until required.

The Future

Artificial skin technology is rapidly expanding beyond burn care into broader organ reconstruction. Engineered tissue is being explored to replace metal and plastic prostheses for joint and bone repair, to grow ear and nose cartilage on polymer meshes, and to regenerate breast and urethral tissues in the laboratory. With continued advances, there is potential to fabricate functional livers, kidneys, and even hearts from human cells, heralding a new era of regenerative medicine.