3D bioprinting aims to create functional transplant organs by layering living cells ("bioinks") derived from a patient's own cells to eliminate rejection. The process begins with 3D digital models from patient scans to define the organ's structure, including its intricate blood vessel networks. printers then deposit bioinks layer-by-layer to form the organ's shape. The critical final step is maturation in a bioreactor, where the printed construct is provided with nutrients and mechanical stimuli to develop into functional tissue. The main hurdle is creating the complex vascularization needed to sustain large organs. Currently, while full-scale organs remain a future goal, the technology is already being used to create simpler tissues like skin grafts and cartilage for transplantation, as well as miniature organ models for drug testing.