Nanowired ultra-capacitor based power sources for implantable sensors and devices

Various examples related to power sources for implantable sensors and/or devices are provided. In one example, a device for implantation in a subject includes circuitry for sensing an observable parameter of the subject and a power source comprising a nanowired ultra-capacitor (NUC), the power source having a volume of 10 mm3 or less. The NUC can have a surface capacitance density in a range from about 25 mF/cm2 to about 29 mF/cm2 or greater. Such devices can be used for, e.g., ocular diagnostic sensors or other implantable sensors that may be constrained by size limitations.