Suppose there was a fuel cell in the size of AAA battery that could convert human blood sugar into electricity. Assume it safe and efficient without causing allergic reaction. But to avoid the risk of it disintegrate and malfunction it should be put in a place that far away to any critical organ as much as possible. It also need to have large amount of blood to supply anytime

Which place in human body would be the best to put that device in?

  • Wouldn't the answer also depend on the purpose of this implant? You wrote it produces electricity - where is this going to? – Marzipanherz Sep 20 at 12:01
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    My physiology knowledge is pretty thin, but I would guess that 'far away from critical organs' and 'large amount of blood supply' are pretty much diametrical to each other. (unless you don't count large blood vessels as organs or start tempering with stuff like VEGF) – Nicolai Sep 20 at 13:34
  • @Marzipanherz In my hypothesis we could use wireless energy transfer with magnetic induction to charge anything outside our body such as cellphone or just implant the cellphone parts in our body – Thaina Sep 20 at 14:27
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    @Thaina I'm not an expert, but you should consider that many body functions are based on electricity as well, and such an implant might interfere with that. Here is a short summary with further references. – Marzipanherz Sep 20 at 14:31
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    Possibly the safest place for it would be in a dialysis machine, or something similar. But dialysis is not exactly "safe," even if it is often the lesser of two evils - the other one being premature death. – alephzero Sep 20 at 15:54

No, there is no safe place.

Devices in contact with blood are subject to thrombosis and embolism. Even devices designed for bio/hemocompatibility are not 100% safe: they are used because the illnesses and diseases they treat are more dangerous than the side effects. Immune responses and platelet activation that occur in the vicinity of a device could also have effects elsewhere in the body, not just in the vessel you could potentially occlude.

Long term, these effects are reduced only because of healing over the exposed surface. You are proposing something which must be in constant contact with blood, which isn't really possible unless you plan to remove and clean it regularly.

On a side note, for the purposes you describe, there are already devices in development based on mechanical motion to do what you suggest (for example, the motion from walking) that are much safer and more feasible than using blood glucose, which is strictly in the realm of science fiction.


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Wendel, H. P., & Ziemer, G. (1999). Coating-techniques to improve the hemocompatibility of artificial devices used for extracorporeal circulation. European Journal of Cardio-Thoracic Surgery, 16(3), 342-350.

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  • My purpose is not just energy harvest (it is one of purpose too). But to have burn calorie and control blood sugar level by disposing it as useful energy without moving at all (which will be good for lazy diabetes people (such as myself)) that's why I want this technology be possible – Thaina Sep 20 at 15:18
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    @Thaina I understand why you might want the technology to be possible; I'm explaining why it's dangerous. – Bryan Krause Sep 20 at 15:25

I believe the best place for this sort of implant would be the femoral vein in the upper leg. It's one of the larger blood vessels, and on the return trip so you don't have to be as concerned about oxygen removal from the blood on whatever apparatus you have. You're far away from all non-peripheral organs as well.

I would also question whether such an implant would be worth all the engineering challenges implicit in a long-term implant in a major blood vessel, but that's tangential to the question.

  • A vein can be worse in some ways because of the risk of pulmonary embolism, or stroke with a patent foramen ovale. – Bryan Krause Sep 20 at 17:25

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