What Is Artificial Skin?

Artificial skin Artificial skin is a skin substitute artificially developed in vitro using the principles and methods of engineering and cell biology to repair and replace defective skin tissue. According to the composition, it can be divided into pure artificial dermis and Active complex skin with epidermal cell layer.

Chinese name: Artificial skin
Foreign name: Artificial Skin

Purpose: Repair and replace defective skin tissue
Category: Skin substitutes

Artificial skin creates a background

Skin helps us maintain the water balance in our body, and it also acts as a barrier against outside bacteria. Without skin protection, severe burns will cause severe dehydration, and some life-threatening bacteria will take the opportunity to disrupt it. How to do it? Transplanting healthy skin to the injured area is an effective way to solve this problem, but where does the healthy skin that can be transplanted come from?

At first, the method of skin transplantation was to "remove the eastern wall and fill the western wall", that is, to take the healthy skin of the patient and transplant it to the burned area, but this method will cause new scars. Moreover, if it is a large-scale burn, there is little left in its normal skin, it is really "all holes, not enough bricks". In addition, people have used corpse-derived skin or skin of heterogeneous animals such as pigs as temporary coverings of wounds, but transplant rejection often occurs. In this situation, research on artificial skin came into being. Artificial skin is a skin substitute artificially developed in vitro using the principles and methods of engineering and cell biology to repair and replace defective skin tissue. Artificial skin is artificially synthesized, which can greatly improve the survival rate of severe burns. The first piece of synthetic skin was invented by Baker and Janos, who is the head of the Department of Traumatology at Massachusetts General Hospital and Janos is a professor of chemistry at the Massachusetts Institute of Technology. Bai Ke has seen many burn patients in his career, and he has been working hard to find a substitute for human skin that can avoid the threat of infection and dehydration. Jarnos has been working on collagen, a protein found in human skin. The two have collaborated since the 1970s, and they discovered that collagen fibers and long-chain sugar molecules can be combined with each other to form a porous material. This material is similar to skin and appears to promote the growth of new skin cells around it if placed on a wound in an experimental animal. Later, the two scientists invented an artificial skin using shark cartilage and collagen from cowhide. This skin contains two layers, the inner layer is chondroitin, a collagen crosslinked with glutaraldehyde, and the outer layer is covered with a silicone membrane. In continued experimental research, they found that this artificial skin can serve as a framework for the growth of new skin tissue and vascular tissue, although these new cells cannot yet grow the hair follicles or sweat glands normally found in the dermis. As the new skin grows, the skin and shark cartilage in artificial skin begin to degrade and are absorbed by the body. In 1981, Bai Ke and Janos first applied the artificial skin they invented to the clinic. The patient was a woman who was burned on half of her body. After peeling off the burned skin, Baike applied a layer of artificial skin and, if conditions allowed, transplanted the patient's unburned skin to the burned area. After three weeks, the female patient's newborn skin grew at an alarming rate and was the same color as unburned skin. The improved product based on this is called integra artificial skin, which not only plays a temporary replacement function, but also can stimulate capillary, fibroblasts and macrophages to gradually grow from the wound into the artificial skin. Bai Ke's research not only saved many burn patients, but also created a new era of scald medicine.

Structure of artificial skin

Artificial skin has two layers: the top layer and the inner layer. The surface layer is made of a silicone rubber film that blocks the attack of bacteria. The inner layer is a special medium that helps injured skin grow.

Artificial skin is used to provide a base layer for transplanted skin. Artificial skin is made from a polymer (a long chain molecule) combined with other chemicals, including those extracted from shark cartilage. Yannis Yannis was the first to treat a third degree burn with artificial skin.

Main functions of artificial skin

The skin not only protects people from being attacked by dirt or bacteria, but also keeps the body's moisture from escaping. When a large area of skin is severely burned or damaged, the doctor must immediately inject fluid and protect the wound. If only the superficial layer of the skin is damaged, new skin will regenerate. If the patient is severely burned, the skin cannot be repaired on its own, and usually superficial skin from other parts of the body must be transplanted to the wound. Creating synthetic skin starts with a piece of dermis, from which a larger area of skin grows. The skin is one of the important organs of the human body and can be completely renewed within 60 days.

Artificial skin is used in the first phase of skin transplantation. Artificial skin protects wounds from infection and promotes the growth of connective tissue. The body's immune system gradually breaks down polymers, and once the patient's own superficial skin is implanted, the wound will heal quickly.

The key to the success of artificial skin transplantation is whether it can quickly vascularize, so that nutritional supply can be obtained as soon as possible after transplantation. On the one hand, they successfully transferred a vascular endothelial growth factor (VEGF) gene into human fibroblasts, enabling them to secrete VEGF and promote vascularization; on the other hand, they passed autologous endothelial cells and fibroblasts through appropriate The method of implanting the dermal stent to induce the formation of new blood vessels completely solves this problem.

Artificial skin preparation

Artificial skin, silk, artificial

Produced by researchers by extracting proteins from silk, this artificial skin is like silk fabrics, with silky smoothness and flexibility. Moreover, it is safer than the most commonly used pig skin material for treating large areas of injury.

This new type of artificial skin. At first glance, it looks like artificial skin, but it is very tough with pull. Take it out of the refrigerator, thaw naturally, disinfect and soak it, and stick it on the wound skin surface. The wound will slowly heal in about half a month. In order to verify its efficacy, scientific researchers have selected 15 large white rabbits for animal tests in 5 batches, and found that after applying artificial skin, the wound with a diameter of 3 cm was healed in less than 20 days.

Artificial skin connective cells

Artificial skin named ICX-SKN

Developed by: Intercytex Group

Called ICX-SKN, this artificial skin is fully integrated with the body after 28 days, closing and healing the wound. In preliminary clinical trials, artificial skin transplantation achieved breakthrough success due to its realistic texture and good durability.

ICX-SKN is a matrix produced by autologous skin cells, namely connective tissue cells. Connective tissue cells can form collagen in natural skin. These connective tissue cells can form a tissue structure similar to real skin.

The experiment only involved small-area local skin transplantation, and the effect on transplantation of large-area burn patients is unknown.

Artificial Skin White Rat Transplant

Artificial skin grafted on a mouse

Developed by: researchers at the Fourth Military Medical University

A small amount of skin tissue was taken from newborn or pre-natal test mice, and after sterilizing, digesting, separating, culturing and other methods were obtained, a sufficient number of cells were obtained, and then tissue engineering was used to reassemble them to successfully develop Epidermal tissue and connective tissue of the skin. The metaphor of this process is to "plant the skin" in the vessel. The experimenters transplanted these artificial skins into white rats. After observation, it was found that the artificial skin not only has some functions of normal skin, but also has a good effect of repairing skin trauma. So far, no immune rejection has been found. It can be said that artificial "ratskin" has been successfully developed. Of course, there is still a gap between this kind of skin and real skin, for example, there are no appendages such as sweat glands and hair.

The advanced nature of this technology is that domestic artificial skin research can only reproduce the epidermis, and the Fourth Military Medical University has developed skin with a second layer of connective tissue. Although the research on artificial skin in China started later than the western developed countries, it has been highly valued by the country. The Department of Burns, Changhai Hospital affiliated to the Second Military Medical University of the People's Liberation Army has established rapid culture and expansion technology of epidermal cells with state funding, and developed a wide range of low-cost, cell-free dermal matrix polymer film and other artificial dermis. The composite skin containing epidermal cells is used to repair deep skin defect wounds. The graft survival rate is high, and some achievements have reached the international leading level.

Artificial skin carbon nanotubes

A new type of artificial skin developed by NASA scientists

The vertical carbon nanotube layer is arranged on the rubber polymer used in cosmetic surgery. It is like implanting a piece of skin. The carbon nanotubes are fixed together by a series of gold wires. These carbon nanotubes are distributed on a rubber-like polymer. This artificial skin combining rubber polymers and carbon nanotubes can transfer the heat from the contact surface to the sensor network, just as the skin can obtain this information in time. When carbon nanotubes increase the piezoelectric induction on the polymer, the sensor is able to generate a signal to the robot's brain.

Vladimir Rumelski, a technical expert at NASA's Goddard Space Flight Center, implants sensors into the skin cover of the robot. This high-tech robot skin can make robots better perform space exploration tasks. Humans Unlike the "body condition" of the robot, in order to realize the intelligence of the robot, the robot also needs to have a certain touch on the sensitive skin.

A robot skin capable of generating pressure and temperature is developed. This artificial skin can detect various things in synchronization with human skin. The transistors used in circuits and semiconductors become "skin organ raw materials" based on carbon atom chains, so that robots can be as tactile as humans.

Although artificial hands are becoming more realistic in terms of movement and flexibility, almost all artificial skins remain at the level of unperceived plastic coatings. John Sim, senior research scientist in the Nanomaterials Synthesis and Attributes Group at Oak Ridge National Laboratory, USA "Using carbon nanotube technology, we can create artificial skin that not only approximates real skin characteristics, but even surpasses these characteristics," said Dr. Pusen.

Heart-lung machine is an important temporary artificial organ as a device that temporarily replaces natural heart and lung function. The artificial heart-lung machine is mainly composed of a blood pump (heart) and an oxygenator (lung). The current types of artificial heart-lung machines are bubble-type artificial lungs and membrane-type artificial lungs. Blood pumps mainly use roller pumps and pulsating pumps. Since the membrane oxygenator is an ideal artificial lung, it has basically replaced the bubble oxygenator. In addition, since the pulsating pump simulates the pulsation of the natural heart, the pulsating pump has a tendency to replace the rolling pump. At present, most of the membrane artificial lungs use hollow fiber type, and the research focus is mainly on improving the performance of hollow fiber through pretreatment. For example: the treatment of hollow fiber heparin can prevent the activation of body fluids and cells and improve their biocompatibility; the use of silicone resin coating can prevent plasma leakage during use; the use of membrane passive coatings such as albumin and carmeda can improve blood compatibility.

Artificial Skin Extended Reading

[1] Brohem CA, da Silva Cardeal LB, Tiago M, Soengas MS, de Moraes Barros SB, Maria-Engler SS. Artificial skin in perspective: concepts and applications. Pigment cell & melanoma research. 2011; 24: 35-50.

[2] Sun Wei. Artificial Skin. Life World. 2011: 58-61.

[3] Binbin. Artificial skin growth can be precisely controlled. Frontiers in Medicine. 2012: 29-.

[4] Bao Jingjing. Artificial skin growing. Science and technology entrepreneurship. 2012: 82-3.