In one form or another and under one name or another, cyborgs were all over the media this past month, with reports of:

• A robot with a rat neuron brain,
• Bionic kidneys and livers,
• Bionic eyes for the blind,
• Brain-computer interfaces for the disabled,
• Artificial gills for aquatic cyborgs, and
• Exomuscles giving us the strength to leap tall buildings in a single bound — or, instead, a genetic manipulation to achieve the same effect with our internal muscles.

Art and the Cyborg

The builders of the “hybrot,” a rat brain in a rudimentary robot body, have now turned a similar creation into an artist. It consists of rat neurons in a petri dish (the “brain”), connected through the Internet to a robot painting arm (the “body”). A computer translates the neural activity of the neurons into movements for the arm. The project is, of course, less about art than about interfacing biological and artificial systems.

The researchers hope to find evidence of learning in the system, presumably in the form of better pictures over time; and presumably there is some feedback mechanism to let the “brain” know how it is doing as an artist. If that is achieved, and the learning process understood at the neuronal level, then neuroprosthetics such as artificial eyes,* eardrums, or limbs could be developed for disabled people — or for robots.

* See also “Bionic Eyes Roundup,” below.

References: Hunter, Dwayne (2003). “Rat Brain Cells Draw with Robot Arm.” Betterhumans, July 10; Keefe, Bob (2003). “Rat brain cells fuel robot’s art.” Toronto Star, July 14.

Bionic Organs

Bioartificial kidneys, livers, and other organs may work wonders, but their full promise cannot be delivered as long as they remain external devices whose cells die after a few weeks. Following remarkable success in a limited trial on patients with acute kidney failure, developers are already pushing forward to the next level: permanent, implantable bioartificial organs.

A key problem is that the pores in the plastic fibers of current extracorporeal bioartificial kidneys and livers, while small enough to block immune cells from entering and destroying the kidney cells lining the inside of the fibers, cannot stop antibodies and other small immune system components. As the kidney cells then die and disintegrate, the detritus causes scarring and clotting in surrounding tissues, sealing off the implant and rendering it dead and useless.

A Boston University biomedical engineer is developing a bioartificial pancreas for diabetics that seeks to overcome this problem through nanotechnology. Silicon capsules filled with living, human pancreatic cells are etched with 12-18 nanometer diameter holes, small enough to block antibody molecules. The implanted capsules worked in rats and produced insulin that maintained the rats’ blood sugar levels through the two-week test period, sustaining rats that would otherwise have perished in a matter of days. Large-animal tests are expected within a year.

Such tiny holes, however, mitigate against filtering the much greater volume of fluid that a kidney has to deal with. A solution being examined is to stretching the nanopores into nanoslits with more efficient fluid dynamics.

Reference: Fairley, Peter (2003). “Saving Lives with Living Machines.” Technology Review, July/August. Fairley’s article is comprehensive and highly recommended reading. See also “Cyborgans” in the August issue of Health Futures Digest.

Bionic Eyes Roundup

Several types of bionic eyes are in development and testing, some in humans. Earlier this year, three people were implanted with a permanent retinal prosthesis that receives signals wirelessly from miniature video cameras mounted on spectacles. The implant’s 16 electrodes stimulate the remaining healthy retinal cells.

Some patients were able to detect if a light was turned on or off, describe the motion of an object, and count objects. But normal vision may need at least 1,000 electrodes. Current technology maxes out at about 100 electrodes in the space available, but even that would mean a considerable vision improvement over a 16-electrode implant and Australian researchers are attempting it. Incidentally, an available “sonic flashlight” handheld ultrasound scanner that displays its images on a 2-inch mirror would give a person with a retinal implant the “x-ray” vision of Superman. (See also “X-ray Glasses” in the Devices section of this issue.)

Another cyborgian approach to treating blindness is a silicon retina under development with 4-5,000 microscopic solar cells, eliminating the video cameras. Researchers are currently looking for a biocompatible material for the solar cells.

A third approach, in phase III clinical trials, is intended for people who have not lost all vision and whose peripheral vision remains intact. The device in this case is a miniature telescopic lens that projects images over the undamaged area of the retina and provides central vision in one eye, leaving peripheral vision to the other eye. A majority of patients implanted with the device in early-phase trials are reported to have “generally improved two to three lines of vision on the eye chart.”

A fourth approach interfaces an external camera directly with the brain through electrodes attached to the visual cortex, essentially bypassing the eye.

References: Sandhana, Lakshmi (2003). “Bionic Eyes Benefit the Blind.” Wired News, July 16; Koerner, Brendan I. (2003). “8 Super Powers: Forget Science Fiction. Here’s the Science.” Wired, Issue 11.08, August.

Brain-Computer Interface

If technology can mediate from the outside world to the inner world of the brain, as in the case of the cortical vision implant mentioned in the previous article, then in principle it can as well mediate in the opposite direction, from the brain to the outside world. Brain-computer interfaces (BCIs) to do just that are making progress, primarily with the goal of enabling the disabled to operate wheelchairs and robotic prosthetic limbs, control their environment (lights, heat, etc.) or communicate via computer.

One research team has created a virtual apartment in which volunteers equipped with a virtual-reality headset and an EEG skullcap (to “read their minds,” so to speak) have been able to switch lights on and off, stop a car, and turn on a television set — just by thinking.

Getting a computer to interpolate a person’s intent through the gross, noisy signals read by an EEG is far from a refined technique, but one team has managed to detect which of several specific mental tasks a test subject performs — such as writing a letter, performing a complex multiplication, and visualizing numbers written on a board — with up to 70 percent accuracy.

European researchers are pursuing the less invasive skullcap EEG approach to enable the disabled to operate a motorized wheelchair using only their thoughts. Early trials suggest that a user could pick up the technique in as few as two days. The desire to move in a particular direction generates a unique pattern of brain activity, which is detected and measured by the EEG and interpreted by AI software which is smart enough to know that “Turn left!” means “Turn left as soon as it there is an opening on the left.” Infrared sensors in the wheelchair will detect walls and objects, and prevent the chair from turning left until it is safe to do so.

External EEG devices such as this avoid the potential problems of implants, but have the drawback of being slower and more coarse grained. To compensate, the wheelchair control system uses a neural network that can be trained to recognize complex patterns and relationships in real time. Yet to be determined is whether there will be a drop in the quality of the EEG signals when the user is actually sitting in the chair as it moves, since the user’s focus on the specific task (say, turning left) will not appear as salient to the system as many other events demand the user’s attention and spark a cacophony of brain activity.

Internal implants are by no means out of the picture. One company hopes to begin clinical trials of its Braingate Neural Interface next year. Braingate builds on experiments on monkeys that were able to play computer games and control robotic devices using thought alone, through an implanted BCI. The trials will equip five severely disabled patients with similar permanent implants.

References: Sandhana, Lakshmi (2003). “I Think, Therefore I Communicate.” Wired News, July 30; Graham-Rowe, Duncan (2003). “Wheelchair moves at the speed of thought.” New Scientist, July 24.

See also an article in the July issue about a brain-powered web browser. This editor’s book, Technology and the Future of Health Care: Preparing for the Next 30 Years (Jossey-Bass, 2000), describes the pioneering BCI implant work done at Emory University in 1998.

Fishborger?

Japanese researchers are building an artificial gill enabling divers to breathe underwater indefinitely. It is made from a material woven from silicone strands covering a membrane filled with a concentrated hemoglobin solution. The hemoglobin soaks up oxygen from the surrounding water and releases it when heated, whereupon it is delivered to the diver’s scuba mouthpiece. The current prototype has been made compact enough for field tests but apparently does not yet deliver enough oxygen.

Reference: Koerner, Brendan I. (2003). “8 Super Powers: Forget Science Fiction. Here’s the Science.” Wired, Issue 11.08, August.

Exomuscles

The U.S. Army is paying MIT’s Institute of Soldier Nanotechnologies $50 million to create a uniform fitted with artificial “exomuscles” made of electroactive polymers* that contract and expand in response to electrical charges, and 100 times stronger than human muscles.

A molecular biologist at Johns Hopkins, is taking a faster route to a similar end, through genetic engineering. He has already created a muscle-bound “Mighty Mouse” – a rat genetically engineered to block expression of the gene that codes for myostatin, a protein that limits muscle growth. Add this to the Designer Babies R Us catalog of available optional extras for your progeny.

* Electroactive plastics have been mentioned several times in Health Futures Digest; see here, for example.

Reference: Koerner, Brendan I. (2003). “8 Super Powers: Forget Science Fiction. Here’s the Science.” Wired, Issue 11.08, August.