Cyborgs, humans whose physical abilities are extended beyond their limitations, are no longer fiction, researchers write in a recently published article. But not everyone agrees about the definition of cyborg.
In "Terminator," Arnold Schwarzenegger probably plays the world's best-known cyborg, a human whose physical abilities are extended beyond his limitations by machines. Thanks to that movie, superhuman machines that kill while running around disguised as a person is an image that a lot of people have in mind when they think of cyborgs. But they are more than that, some researchers say.
The term cyborg also includes people wearing pacemakers or the disabled who regain the use of their limbs with the help of machines, according to scientist Christof Niemeyer from the Karlsruhe Institute of Technology. His research focuses on the interfaces between technical devices and living cells. In "The chemistry of cyborgs: interfacing technical devices with organisms," Niemeyer and his colleagues summarized what cyborg technology can already do.
"Nowadays, rejection is no longer a problem. We have very good coatings and special alloys." he told DW.
A good example are titan alloys. The patient's body may recognize the implant as a foreign object but it doesn't identify it as a threat. In most cases, the body enwraps the implant with tissue. Many synthetic polymers are also good for making body parts and they can serve as a coating over a metal part and protect it from the direct contact with the immune system. For example, polyethylen is used for artificial sockets of hip replacements.
Telling nerve cells what to do
But researchers want to do more than incorporate implants into the body: they want the devices to interact with it. Pacemakers for example send signals to the heart muscle cells so that they contract at a given time.
To treat neurological disorders like Parkinson's or severe depression, doctors can implant electrodes into the patient's brain, which send electronic signals to a specific part of the body. This works, but today's deep brain stimulation is like driving a metal bar through thousands of nerve cells, according to Niemeyer. So it’s not possible to interact with one specific single nerve cell.
"We have to develop techniques to activate very specifically one kind of ionic channels in a nerve cell membrane," Niemeyer says.
Ionic channels are microscopic structures that regulate how stimuli are transmitted in a nerve cell. The challenge is to control them with machines, Niemeyer says.
Cyborg technology can enable the disabled to move their limbs. Researchers have already managed to treat paralysed patients this way. Patients can seize objects with a robotic hand using their willpower.
Researchers have also managed to control cockroaches and other insects. Tiny electrodes were implanted into the insects and certain nerves were stimulated with electricity, allowing the researchers to control the movements.
US-based company Backyard Brains even offers modified cockroaches for sale on the Internet. The buyer can control the left and right movement of "the RoboRoach" using his smartphone and a BlueTooth connection: something the company markets as "the world's first commercially available cyborg."
But if remote-controlling an insect is already possible, the question is whether it will one day be possible to assume full control of a person with the help of a few electrodes.
"Presently, these [electric] signals [from outside] are not suitable for controlling the entire organism, a scenario suggested in numerous examples of cyborg fiction," Niemeyer and his co-authors write. "The brains of most living organism are too complex."
'Cyborgs don't exist'
But not all scientists agree with the Niemeyer's use of the term cyborg.
"Maybe they will exist in the future, but at the moment there aren't any cyborgs yet," says Dieter Sturma, director of the German Reference Centre for Ethics in the Life Sciences in Bonn.
A human being with implants or electrodes inside his brain is still the same person and not a cyborg, he explains.
The bioethicist believes that using devices in the human body is not much of an ethical problem when the technical devices are used for medical therapy.
"When technical systems reduce the suffering of a patient, we should always be open for them," he says, while warning that it becomes a problem if the technology aims to enhance people.