Electric circuits are offering more and more possibilities as a means to help diagnose and monitor patient health. For example, devices can be implanted under the skin or within the body to measure physiological signals. To be viable, these devices must be small and reliable.
Integrated circuits are electronics at microscopic scales. One thousand micrometers (mm) fit into one millimeter (mm), so a lot of electronics can be packed into a small circuit.
This image is a schematic of a 180mm x 140mm circuit I have been designing. Each colour represents a different layer in the circuit, wires, different chemical implants and connections.