| Developers: | Tsinghua University |
| Date of the premiere of the system: | 2020/08/14 |
| Branches: | Pharmaceutics, medicine, health care |
Main articles:
2020: The announcement of printing living cells on a stomach model wall
On August 14, 2020 it became known that the Chinese scientists created a prototype of the bioprinter which can treat defects of a wall of a stomach, printing on it from within "patch" the hydrogels containing cells of the corresponding fabrics. He is brought in a stomach on a gullet like the endoscope, and then opens the put parts and begins to put layers of hydrogels. Authors of development showed operation of the bioprinter on stomach model, having printed on its internal surface layers from cages of an epithelium and smooth muscles. Article is published in the Biofabrication magazine.
As it was explained, bioprinters are devices which can create volume constructions from the materials containing living cells of the person or other animals that afterwards they turned into full-fledged fragments of fabric. So far to printing of full-fledged bodies — the ultimate goal — for August, 2020 this technology, however, is far. One of problems which prevents creation of artificial organs or their fragments is that for treatment of defects of internals it is necessary to perform invasive operations.
Recently the group of scientists from Belgium, China and the USA found the solution of this problem. They developed the method allowing to enter liquid procurement under skin, and then to cure it using infrared radiation. The method showed previously quite good results, but it can be used only on the fabrics located superficially under skin.
Wenxiang Zhao and Tao Xu from National Tsing Hua University created 3D - the bioprinter which can be used even in digestive tract without surgical cuts of fabrics. By the principle of work it is similar to the endoscope, but with wider tube with a diameter of three centimeters. It is more, than at the endoscopes used for August, 2020, but diameter is limited only on the end where the printer is located, and in other parts where only a few cables and a tube are located, it can be made much less.
The printer on the end of a tube has construction of the delta robot: it consists of three parts connected on the end between which the tube for hydrogel supply is located. The principle of operation of the delta robot is that each of three sections is controlled one simple motor in the basis, but together they can move the end in any direction. The nozzle for printing is installed in the printer on the end of the delta mechanism. During mechanism section printing partially go beyond diameter of a tube, but for the period of input of the device in a gullet they can develop.
Hydrogel for printing consists of water solution of gelatin and alginate of sodium and also the cages of the necessary type added to it. Authors created two types of "ink" for printing: with cages of a gastric epithelium or with cells of gastric smooth muscles in concentration 1.5 × 10-6 cages on a milliliter. Researchers tested the printer for models of a human stomach from the polymer created on the basis of KT-pictures of a stomach. The printer printed trellised structure from two layers repeating arrangement of fabrics in a stomach. The low layer was printed with gel with muscle cells, and upper epithelium cages. After that the printer gave the calcium chloride acting as the connecting agent through a nozzle.
After printing researchers checked survival of cages right after drawing and also in three, seven and ten days. They used for this purpose two substances, one of which is absorbed by living cells and create substance with green fluorescence, and the second gets through membranes of dead cages, contacts their DNA and fluoresces in red color.
The analysis of the printed fabrics showed that in the first days the survival was about 94 percent, and only after ten days decreased a little, at the same time having all the same remained at the level of higher than 90 percent. Besides, cages actively shared, proliferirovat and changed the morphology. Thus, when testing for stomach models the method was successful. Further scientists will try to repeat results in actual practice.[1]
Notes
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