"...To keep the implants small, many microstimulators will have no battery."
If there are no batteries being used for the microstimulator, how is the microstimulator charged? Is it a super-capacitor that is used on the microstimulator instead of a battery which gets charged through the living tissue when the "credit card sizex" charger is placed on the skin?
Delivering power and commands to an embedded nano blood biochemical analysis 'lab', and then receiving results would be an extremely important advance in diagnostic and preventive medicine. Using the technology for drug delivery and, or, various stimuli would likewise be extremely important.