Science: New bio-printer heals chronic wounds
Open wounds cause half of all leg amputations and can be life-threatening. Therefore, researchers have now developed a printer where the ink is the patient's own cells. Trials show that the printer heals wounds that were previously impossible to close.
The patient's own cells turn into printer ink
Detailed 3D scans, printer ink made from skin cells and nozzles that are programmed to follow the wound's special structure - the new bioprinter can seal wounds that previously required donor skin, and speed up healing by several weeks.
The researchers cut a piece of the patient's healthy skin and used the tissue sample to isolate the so-called horn and fibroblast cells that make up the outermost and middle layers of the skin, respectively.
Then the cells are placed in a dish together with a powerful growth cocktail of hormones and amino acids that cause the cells to grow and divide.
The researchers mix the skin cells with special water-soluble glue - a so-called hydrogel. The hydrogel is a biodegradable material that glues the cells together and creates a kind of molecular scaffold, where the cells can grow and multiply. The hydrogel and the cells form the so-called bio-ink that is poured into the nozzles.
Using data from a detailed 3D scan of the wound, the printer's nozzles can place the bio-ink so that it fits precisely into the wound's structure. The middle layer of the skin, the skin of the skin, is filled with fibroblast cells, and the outermost layer of the skin, the epidermis, is filled with horn cells. The cells stay in the hydrogel until they grow together with the tissue around the wound.
American actor Christopher Reeve became world-famous in the 1980s when in the role of a movie hero, The Superman saved the world from countless villains. Still, in reality, the person behind the hero character came to fight an entirely different battle.
A tragic riding accident in 1995 led to Christopher Reeve being paralyzed from the neck down. He became wheelchair-bound and bedridden around the clock.
The paralysis caused him to develop huge pressure ulcers on the areas of the body that were constantly resting on a surface, as the pressure from the bodyweight blocked the small blood vessels in the skin and created dead skin tissue.
On October 10, 2004, his body resigned. The bacteria that entered the body through the open pressure ulcers had infected the blood and spread to the internal organs through the bloodstream.
The doctors tried to fight the infection with antibiotics, but without success. Finally, the actor’s heart stopped beating.
And Christopher Reeve is far from alone about having been aware of the severe consequences of chronic wounds. According to a study by the scientific journal Wound Repair and Regeneration, seven million people suffer from permanent wounds in the United States alone.
And as many as 28 percents of patients usually die within two years due to illnesses and complications that follow.
Also, patients with open wounds are estimated to account for as much as six percent of total hospital care expenditures in the developing countries, which corresponds to an annual cost of €30 billion.
But thanks to researchers from the Wake Forest Institute for Regenerative Medicine in the United States, help will be available soon. The researchers have developed a new bio-printer, which is the first of its kind that can print two layers of skin cells directly on the patient’s wounds at the hospital bed.
Time can be crucial for quick and effective healing in the future – in the end, it can be the difference between life and death.
The body’s defense defeats enemies
The skin is vital to us because as a natural armor prevents viruses, bacteria, cold, heat, and other external threats from penetrating to the bloodstream and the body’s other organs.
If there is a hole in one or more layers of the skin, then the body is in danger. But unlike almost all other organs, the skin has an outstanding ability to repair itself.
The repair is initiated by the immune system’s various white blood cells, which arrive at the wound area through the bloodstream in just a few hours and secrete many substances that promote wound healing.
Unfortunately, in millions of people around the world, the skin’s own toolbox doesn’t work quickly or effectively enough to repair superficial wounds.
The ability to heal wounds can deteriorate with age. This is partly because the blood supply is weakened, so that the skin is both less durable and ultimately becomes harder to recover.
Compilations show that one in 100 men and women over the age of 65 suffers from chronic wounds – four times more than in the younger population.
But the largest group of chronic wounded patients is found in patients with diabetes, who are particularly vulnerable due to lost feeling, and poor circulation.
Studies show that open wounds caused by diabetes are the cause of 50 and 70 percent of all bone and foot amputations.
A large part of the amputations can hopefully be avoided with the help of the new bioprinter. The printer takes up so little space that it can stand next to the hospital bed.
This is important because rapid treatment without the need to move patients from one place to another is crucial to prevent infections and increased scar tissue.
Scanner maps the wound
The new bioprinter works by doing a 3D scan of the entire wound with a laser. The scan provides a three-dimensional map of the wound’s elevations and recesses, which researchers can use to navigate the printer nozzles.
The researchers then cut a small portion of the patient’s healthy skin and isolate the so-called horn cells that primarily make up the outer layer of the skin, the epidermis. After that, the fibroblast cells that mainly make up the skin’s middle layer are isolated, the leather skin.
The two different cell types are then allowed to grow and multiply in a petri dish clothed with amino acids, vitamins, and hormones – a so-called nutritional medium.
Finally, the researchers mix the cells with a special water-soluble adhesive, the so-called bio-ink, which is printed directly on the wound.
The researchers from the Wake Forest Institute for Regenerative Medicine are currently trying to get clinical trials on humans approved. So far, they have only tested the bioprinter on mice and pigs – with good results.
Three weeks after the treatment, the wounds in the trial had been replaced by a fine skin layer, which is two weeks less than the healing time for traditional skin transplants.
Another advantage of the bio-printer is that the skin cells are the patient’s own. In large and severe wounds that require donor skin, there is a risk that the body’s immune system perceives the transplanted skin as a foreign body and repels it.
Therefore, patients undergoing major skin transplants must take immunosuppressive drugs. However, patients who are treated with the bioprinter need not worry. Besides, they do not have to wait for a possible donor.
The treatment of open wounds also leads to development opportunities in other areas. At the Wake Forest Institute for Regenerative Medicine, more than 300 researchers are currently working on developing and testing bioscripts so that in the future, it will also be possible to print functional hearts, kidneys, and other organs directly from the printer.