No matter how perfect the mechanism is, sooner or later it will break. So is the human body. Gradually wearing out, it ceases to perform its tasks. Fortunately, it is now possible to replace most of its parts, restoring the lost functions.
Ancient dentists inserted teeth, carved from stone or pieces of shells, to replace the fallen ones, securing them with gold wire. Modern implants were invented only in 1938. They are made from porcelain, acrylic and resin composite. The operation to implant artificial teeth takes from two to eight hours, depending on the level of complexity. First, all excess is removed, and then four or six implant pins are installed in the gum, to which the holders that fix the prosthesis are screwed with titanium screws.
The loss of an arm is no longer a sentence. If earlier instead of limbs they offered metal products, sometimes sheathed with leather for beauty and equipped with a pair of hooks, now bionic prostheses have been developed that not only move, but also “feel”. Tactile stimulation occurs thanks to electrodes implanted under the skin, which are attached to the nerves of the rest of the hand.
Scientists have developed an algorithm that converts the "recoil" when you touch various objects into a signal that goes through the prosthesis to the nerves and then to the brain. In 2015, a 28-year-old paralyzed patient was able to touch objects using a bionic hand. During the experiment, he was blindfolded and his ears were plugged, so he controlled the actions of his hands only with the help of sensations. The patient quickly learned to take different things, to determine their shape and texture.
Joints are one of the most vulnerable parts of the body, especially in the elderly. Their first artificial counterparts were made of ivory at the end of the 19th century. Then they were made from glass, steel and acrylic. However, all materials, including modern synthetic ones, have a rather low wear resistance, therefore, due to constant interaction with the joint cup, they are erased. Now scientists are trying to solve this problem radically by strengthening the implant with polyethylene and carbon nanotubes. The service life of such an endoprosthesis will be about 15 years.
The main problem of materials for artificial joints is their low wear resistance. AP Photo / M. Spencer Green
There is also the problem of making artificial bones. Scientists have been looking for a non-toxic and durable alloy for a long time. Titanium was generally suitable for this, but it does not have the flexibility inherent in human bones. As a result, the living tissue ceases to receive stress and dies off, because the body no longer needs it. The connection of the tissue with the implant disappears, it loosens, so it needs to be replaced. To improve the properties of titanium, it is mixed with zirconium and niobium. Bone of any shape can be made from such an alloy using 3D printing.
Making an artificial eye is much easier. The problem with doing this is getting him to see. When people lose sight, their retinas no longer send signals from photoreceptors (rods and cones) to the brain, so it needs to be completely replaced. The implanted structure is a plate on which, among other things, components similar to photoreceptors are located. They take over the functions of color-discriminating cones, which work to provide vision in daylight. At the end of 2017, two retinal replacements were performed in Russia. The first patient already sees the outlines of large symbols.
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So we got to the most important part of our body - the brain. To date, scientists have managed to grow a certain rudimentary brain the size of a pea, however, so far from rat tissue. Let's say that a full-sized brain will also be grown, but how to transfer information there from the previous "data warehouse"? Our knowledge is an emerging connection between neurons, which is not yet possible to repeat exactly. It is no coincidence that half of those who used the technology of posthumous freezing did not want to preserve the whole body, which can be changed almost completely, but only the brain, the full reconstruction of which is still in question. In fact, we are talking about an artificial copy of our intelligence.
Sooner or later, the obstacles to the creation of any artificial organs will be removed, but will it be a boon? Knowing that we have high-quality, durable, fatigue-free artificial organs at our service, won't we take less care of our body?