Last month we wrote about bionics—the integration of human and machine, resulting in “cyborgs”—from a nervous system perspective. Specifically, we described developments in the “brain–machine interface” that connects electromechanical bionic devices—artificial limbs and organs—with the human nervous system. But bionics is not just about artificial devices. It is also about artificial materials that more or less (increasingly, more) mimic human tissues and cells.

We offer no essay this month. Instead, we provide a simple descriptive selection of recent exemplary advances. The selection serves, we hope, to show that “trans-humanism”—a movement which (according to Wikipedia) aims to eliminate aging and greatly enhance human intellectual, physical, and psychological capacities—may be not quite as preposterous, or as distant if you are inclined to be open-minded or generous, as it sounds.

Artificial Bone

An artificial bone graft called FortrOss, on the market in the US since 2008, mimics the nanostructures of natural bony tissue and is thus accepted by the body. It could eventually have a rival in the form of artificial bones made of chemically and heat-treated rattan wood. In animal trials using sheep, they are turning out to be strong and durable enough to last a lifetime, with no signs of rejection or infection in the sheep. However, human clinical trials are still about five years away, so FortrOss can breathe easy for a while.

Artificial Muscle Advance

Carbon-nanotube ribbons stronger than steel, as elastic and flexible as rubber, light as air, able to withstand temperatures ranging from -190 to over 1,600 °C, transparent, and electrically conductive have been developed for use (among other things) as artificial muscle fibers for prosthetics and robotics. The ribbons change shape and size in response to electrical or chemical signals and can exert 100 times more force than natural human muscle over the same area.

Sheets woven from the ribbons currently generate 32 times as much force per unit area as heart muscles, though electroactive polymers generate up to eight times as much force per unit area as the nanotube sheets. Polymer actuators also need just a few volts to contract, vs. three to five kilovolts for the ribbons—too strong for use in humans and risky even in robots. But it’s early days, and future development may improve the ribbons’ performance. Already, they can change dimensions much faster than polymer actuators.

Artificial Collagen for Cartilage Repair/Replacement

A stable and ultra-strong artificial human collagen has been developed that could be used to treat arthritis and other conditions that result from collagen defects, as well as burn and other wounds. Bovine-derived collagen carries the risk of rejection in human patients.

Artificial Arteries

An artificial artery for use as a bypass graft is about to begin human trials in coronary artery and lower-limb arterial surgery. Made from a polymer material, the graft mimics the natural pulsing of human blood vessels, which enables them to deliver nutrients to the body’s tissues. Other plastic grafts made with nylon work well for larger grafts but are less successful for grafts of less than 8mm. The new artificial artery has been designed to mimic the natural artery’s characteristic strength, flexibility, resistance to clotting, and rhythmic pulsing in sync with the heartbeat.

Artificial Blood Platelets

Synthetic blood platelets capable (like natural platelets) of clotting have been shown to quickly reduce bleeding in rodents with severed arteries. The nano-sized platelets stick to natural platelets to stanch bleeding more effectively than an expensive clotting drug currently used to stem uncontrolled blood loss. The platelets do not accumulate in non-injured tissue to form dangerous clots. At unnecessarily high doses the platelets led to breathing issues in some of the tested mice. Tests in larger animals are planned. It will be some time before human trials are attempted.

Artificial Red Blood Cells

Biodegradable, biocompatible particles with the size, shape, and flexibility of red blood cells have been created that could transport not just oxygen but also drugs and imaging agents. So far, the particles have been shown to be capable of compressing sufficient to squeeze through capillary-sized tubes, carrying drugs, and encapsulating iron-oxide nanoparticles as a potential contrast agent for MRIs. The next step is to find out from animal tests whether the particles will remain in the bloodstream for as long as two to three months, like real red blood cells, without arousing an immune response.

Artificial Larynx

A prototype artificial larynx that tracks contact between the tongue and palate to determine which word is being mouthed, and uses a speech synthesizer to generate sounds, is expected to be a great improvement over existing devices used in many patients with advanced laryngeal cancer who have their voice box removed. The system contains 118 embedded touch sensors on a “palatometer” placed in the mouth, and an external synthesizer that (after training) translates the touch patterns into words and speaks them. A predictive-analysis system considers the last word mouthed to help determine the next word. The result is 94 percent accuracy, excluding words the system classifies as “unknown” and skips to avoid “some very difficult social situations,” as a researcher put it. There remains much development work to do before the device will be ready for market.


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