A British scientist claims to be the first human to have been infected with a computer virus after he contaminated an electronic chip which was inserted into his hand.
Dr Mark Gasson, of the University of Reading, said the device was programmed with a virus which could transfer itself to other electronic systems it came in contact with.
Any other chips that interacted with the infected systems would also contract the virus, he said, raising the possibility that in the future, advanced medical devices such as pacemakers could become vulnerable to cyber attacks.
Dr Gasson's chip, a refined version of the ID chips used to track animals, has been programmed to open security doors for him and to unlock his mobile phone automatically.
The results allegedly prove the principle that in future, human implants like this could contaminate increasingly complex medical devices such as pacemakers and cochlear implants.
Dr Gasson told BBC News: "With the benefits of this type of technology come risks. We may improve ourselves in some way but much like the improvements with other technologies, mobile phones for example, they become vulnerable to risks, such as security problems and computer viruses."
Implanted technology has become increasingly common in the United States, where medical alert bracelets can be scanned to bring up a patient's medical history.
Professor Rafael Capurro, of the Steinbeis-Transfer-Institute of Information Ethics in Germany, added: "If someone can get online access to your implant, it could be serious.
"From an ethical point of view, the surveillance of implants can be both positive and negative. Surveillance can be part of medical care, but if someone wants to do harm to you, it could be a problem."
Dr Gasson, however, said technology with surveillance capabilities could in future become widely used for non-medical purposes.
He said: "If we can find a way of enhancing someone's memory or their IQ then there's a real possibility that people will choose to have this kind of invasive procedure."
The project is not the first time Reading University scientists have combined electronics and the body in futuristic experiments.
In a separate project in 2008, experts created a robot that used cells from the brain of a rat to make decisions, in order to learn more about how the brain functions.
The robot, known as an "animat", interpreted electrical signals from the cells to navigate itself around a laboratory without bumping into obstacles.
Researchers said it could eventually help them design treatments for diseases such as epilepsy, Parkinson's and Alzheimer's.