The topicality: the shortage of donors is a serious medical problem, the tendency is that there are fewer and fewer patients who need donor organs. In addition, transplantation means a lifelong use of immunosuppressants for the recipient, and this makes people more susceptible to illness and can lead to cancer.
The relevance of the study is that bioprinting allows you to abandon the two main problems of transplantology and offers promising solutions in the treatment of organ failure for which the future.
The purpose: to study the method of 3D-bioprinting and its application in medicine. Materials and methods: Analysis of domestic and foreign sources in order to become familiar with the mechanism of 3D bioprinting and review of the spectrum of application of tissue bioconstructs
Results: Bioprinting is a biomedical application of layer-by-layer three-dimensional printing to solve the problem of obtaining copies of living organs for subsequent transplantation to a patient, computer-controlled technology or digital three-dimensional printing.Computer-generated graphic design of the body in a standard 3D graphics data exchange format is a mandatory attribute of bioprinting, three-dimensional tissue bioconstructs should form the tissue fibrous base themselves without an additional polymer skeleton / matrix. Bioprinting is a technology of bioproduction, based on the principles of synthetic anatomy: from the particular to the general through the reconstruction of the organ structure according to the known laws of physiology and developmental biology [1, 2].
3D-bioprinter is a biological variation of the reprap technology, a device capable of creating organs and tissues, layer-by-layer by applying cells to each other. The sterility of the bioprinting process is ensured by placing the bioprinter in a sterile box equipped with special systems to create an optimal and comfortable environment for working with living tissue. Bioprinter uses two types of “ink” - cells of different types and auxiliary materials (collagen, growth factors, supporting hydrogel), designed to strengthen the created structure until natural bonds form between the cells [3, 5].
Modern printers have nozzles with a predetermined volume of capacity, allowing the dispensing of bioink and bio paper. Three nozzles are designed for bio-ink. In each nozzle can be placed either spheroids of various types and diameters or various cell suspensions, materials. Each nozzle can be given the number of dispensed tissue spheroids, or for example, the thickness of the printed layer, as well as other parameters. Two nozzles of a different type - designed for bio paper [4].
Various methods of applying bio paper are possible, such as spraying (Nordson nozzle) and dispensing (Fishman nozzle).
Scaffold is an implantable or injected construct, the appearance of which varies depending on the type of tissue grown. Despite this, three main properties must be present in this three-dimensional structure: porosity, adhesiveness, and mechanical integrity, which is similar to the native projected structure. Scaffold allows delivery of progenitor cells and growth factors while maintaining the desired shape of the implant.
Collagen is used as a material for the production of scaffold; however, it is difficult to predict the process of its biodegradation; therefore, in most cases, chitosan, which is a derivative of chitin, is used, in addition, it has anti-bactericidal properties. What does the “production chain” of bioprinting consist of? The technology is based on tissue spheroids. This is an elastic clot of living cells (from 1000 to 10 000 units) with a size of 200-300 microns, which is used in the works of Forgach, Mironov, Wen and other researchers as the main material for bio fabrication. In fact, it is a brick of a tissue building, which is created in artificial conditions. A simple version of this structure can be obtained by incubating suspensions of various patient cells in a small volume of culture medium, for example, in forms in the form of small honeycombs.
Currently, a study on embryonic tissues has shown that the joint cultivation of human cells from the umbilical vein and mesenchymal stem cells significantly increases their proliferation, in contrast to the cultivation of monoculture cells of the umbilical vein. This can be the result of the interaction of two types of cells through an intercellular interaction and a diffuse paracrine signal. It is well known that stem cells can produce bioactive growth factors, such as vascular endothelial growth factors, thus stimulating the growth of cells from the umbilical vein. More importantly, stem cells have the ability to proliferate in vitro and differentiate into different cells, such as osteoblasts, chondrocytes, adipocytes, myocytes, as well as vascular cells, depending on the state of the environment. Differentiation of stem cells occurs in the basal medium and culture medium mixed in proportions of 1: 1.
Conclusions: According to scientists, the future of cellular technologies is the use of autologous (cells originating from the patient’s own body) adult cells.
Firstly, the best bank for storing patient cells is himself.
Secondly, reprogramming technologies allow to correct those defects of the genome that have arisen during the patient's life.
Thirdly, autologous cells do not have an artificially introduced risk of tumors compared with embryonic cells.
List of references:
- Gaurav Shah, Bernard J. Costello. Soft Tissue Regeneration Incorporating 3-Dimensional Biomimetic Scaffolds - Oral and Maxillofacial Surgery Clinics, Volume 29, Issue 1, Pages 9-18, 2016
- Jinah Jang, Hun-Jun Park. 3D printed complex tissue construct using stem cell-laden decellularized extracellular matrix bioinks for cardiac repair - Biomaterials, 2017-01-01, Volume 112, Pages 264-274, 2016
- Weitao Jia, P. Selcan Gungor-Ozkerim. Direct 3D bioprinting of perfusable vascular constructs using a blend bioink-Biomaterials, 2016-11-01, Volume 106, Pages 58-68, 2016
- Mironov Vladimir Aleksandrovich. Vsled za sozdatelem. Tehnologii bioprintinga // Nauka iz pervyih ruk. 2013. #4 (52) S.14-25.
- Obrazovatelnyiy portal o tehnologii biopechati [Elektronnyiy resurs]. - http://edu.bioprinting.ru/