Implantable sensors can also work with a series of medical devices that administer treatment automatically if required. Tiny implantable fluid injection systems can dispense drugs electrically on demand making use of microfluidic systems, miniature pumps, and reservoirs. Initial applications may include chemotherapy that directly targets tumors in the colon and are programmed to dispense precise amounts of medication at convenient times, such as after a patient has fallen asleep. Lupus, diabetes and HIV/AIDS applications are also being investigated.

Implantable sensors that monitor the heart’s activity level can also work with an mplantable defribulator to regulate heartbeats. These devices are used with microprocessors to deliver electricity that keeps the heart in rhythm when levels go above or below the person’s normal heart range.

Implantable MEMS devices are also fitted on prostheses to mimic the stability and strain of natural limbs. An artificial leg being developed uses sensors to measure load on the foot, knee angles and motion over 50 times per second. The sensors work with an electronically controlled hydraulic knee to improve its stability.

Implantable medical devices that are greater than 1mm in diameter might unfavorably alter the functions of surrounding tissue. Smaller implantable devices with non-intrusive or minimally-intrusive systems will likely contain nanoscale materials and smaller systems approaching the nanoscale.

Functional Electrical Stimulation (FES) is a method for treating people to regain the use of their paralyzed limbs by electrically stimulating paralyzed muscles with implanted electrodes. Researchers at Aalborg University in Denmark are applying nanostructures to the electrode surfaces to improve biocompatibility and acceptance in the neural/muscle tissue. When placed within a cell membrane, the nanostructures form a bioelectric interface with the neuron or muscle cell that enables the intracellular potential of the cell to be observed and manipulated.

Researchers at Aalborg are also using nanostructures to activate denervated muscles caused by injuries to the lower motor neurons located in the spinal cord. This can result from traumatic spinal cord injury, strokes in the spinal cord, repeated vertebral subluxation, brachial plexus injuries and peripheral myopathies such as polio which destroys the nerve cells controlling muscle (i.e. denervated muscle).

The muscle fibre membrane is incorporated with potential-generating nanostructures that change the transmembrane potential of the muscle fibre and improves the extracellular electrical stimulation. Muscle fibre activation is achieved by illuminating the incorporation site on the muscle fibre to optically activate denervated muscles.