How does tissue engineering create replacement tissues such as skin grafts and heart valves?

Tissue engineering creates replacement tissues by integrating cells and growth factors with scaffolds made from natural materials, such as collagen, or synthetic biodegradable polymers.21

To create these tissues, human cells are seeded onto a scaffold and incubated in a medium containing growth factors that stimulate the cells to grow, divide, and spread across the structure. As the cells organize, they form a substitute tissue that can be implanted into the body, where the scaffold is eventually absorbed or dissolved. Advances in bioprinting and the use of decellularized organ structures allow for increasingly sophisticated bioartificial tissues.231

While skin grafts are successfully produced using these methods to treat complex wounds like burns, heart valves are often replaced with mechanical prostheses or biological homograft and heterograft valves. Unlike engineered tissues that integrate with the body, mechanical valves are typically made of materials like stainless steel or Dacron and require ongoing anticoagulation therapy to prevent blood clotting.2456