Synthesis of cell structures

The shortage of organs for transplantation has provided the impetus for increasing investigation into the development of artificial organs. Organs themselves consist of three-dimesional structures made up of cells with different degrees of specialization, an extracellular matrix, and a variety of tubes and ducts to transport their products and waste into the blood stream. One can imagine the need for an artificial pancreas to treat patients with type I diabetes mellitus, an artificial liver to treat acute fulminant hepatitis and as a bridge to transplantation for other liver diseases, an artificial kidney to replace dialysis, artificial hearts and lungs, artificial skin, artificial endocrine glands, artificial reproductive organs, and artificial vision. The inherent complexity of each of these devices is related to both the incorporation of cells and our ability to create three-dimensional structures for them. Autologous cells, which would not require immunosuppression, create a need for complex processes to harvest the host’s own cells, when available, and require additional interventions. The use of homologous cells or xenogeneic cells creates a level of complexity, immunologically, for which there clearly is not a simple solution. Nevertheless, the quest for artificial organs will continue unabated, and the possibility that microfabrication and nanotechnology can contribute to this process is substantial.