Human implantable technologies

Human implantable batteries belong to a unique class of land applications that defines yet another set of strict requirements. There is the necessity for reliability, with no tolerance for the risk of failme because in the case of fiiUy implantable devices, a smgery is required each time the battery needs to be replaced. The cells must be small and provide reliability to deliver adequate cycle life to gain the most out of the procedure to implant them. Depending on the type of implant, the surgery is sometimes followed by a lengthy recovery period. Additionally, due to the direct contact with human tissues, the cell technology for this application must be well-sealed, especially with the use of a nonaqueous electrolyte. 

Today, with the exception of bone marrow for hematopoietic reconstitution, therapeutic cellular transplantation is an emerging technology. In recent years novel approaches in the potential restoration of function through cellular transplantation have included the use of fetal human or xenogeneic neural tissue for Parkinson s disease, ectopically implanted pancreatic islets for diabetes, Schwann cells and olfactory ensheathing glia for spinal cord injury, encapsulated chromaffin cells for pain, and various types of stem cells for the treatment of diabetes, cardiac disease, and central nervous system injuries or disease [2], There have also been trials of encapsulated cells to provide enzymes that either remove toxic products or provide activation of prodrugs to therapeutics, usually anticancer derivatives. 

In the early 1930s during his tenure at Rockefeller University, Charles Lindbergh, the aviator, first contemplated preclinical development of manufactured human organs (neo-organs) for implantation into the body [1], However, it took 50 years of scientific research and technology advancements... 

Technology has made modern batteries smaller, safer, and more dependable than our crudely constructed copper-zinc voltaic cell. In fact, the silver cell (Figure 9.11) is sufficiently safe and nontoxic that it can be implanted in the human body as a part of a pacemaker circuit that is used to improve heart rhythm. A rather futuristic potential application of voltaic cells is noted in A Medical Perspective Turning the Human Body into a Battery on page 261. 

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