Tissue engineering involves using cells, biomaterials, and growth factors to repair or replace damaged tissues and organs. It combines three main components: cells from the patient or donor, biochemical signals to guide cell growth, and scaffolds that support new tissue formation. Researchers are working on techniques like autologous chondrocyte implantation to regenerate cartilage, intervertebral disc regeneration, encapsulating pancreatic islets, and developing bone and cartilage substitutes using stem cells.