3D bioprinting is a technology that uses a 3D bioprinter to create a cell scaffold, and then seed cells into the scaffold to allow cells to grow. Bioprinting uses a layer-by-layer manufacturing method, using bioinks, to create cell scaffolds that mimic living tissue and can generate precisely controlled 3D tissue structures with tissue-like complexity. It has great applications in the fields of medical and tissue engineering. Bioprinting can currently be used to print tissues and organs for drug testing, as well as to make cell scaffolds. These scaffolds can be used in articular cartilage or ligament regeneration techniques
1. The concept of 3D bioprinting
With the development of biological 3D printing, its concept is also continuously extended and expanded. At present, biological 3D printing can be divided into two concepts: broad and narrow. In a broad sense, 3D printing that directly serves the field of biomedicine can be regarded as the category of bio-3D printing, while in a narrow sense, the process of manipulating cell-containing bioinks to construct active structures is usually called bio-3D printing.
※ In a broad sense, biological 3D printing can be roughly divided into 4 levels:
① Manufacture of structures without biocompatibility requirements, such as 3D printing of products currently widely used in surgical path planning.
② Manufacture of non-degradable products with biocompatibility requirements, such as titanium alloy joints, silicone prostheses for defect repair body, etc.
③ Manufacture of biocompatibility requirements, degradable products, such as active ceramic bone, degradable blood vessel stents, etc.
④Narrow bio-3D printing, that is, manipulating living cells to build biomimetic three-dimensional tissues, such as printing cell models for drug screening and mechanism research, liver units, skin, blood vessels, etc. The process of manipulating cells in bio-3D printing can also be called cell printing ( cell printing)
※ In a narrow sense, the concepts of cell printing and bio-3D printing can be interchanged. In addition, organ printing is sometimes seen.
The concept of organ printing, usually this concept can also be considered interchangeable with cell printing and biological 3D printing in a narrow sense
2. The core material of 3D Bioprinting is bioink
3D printing organisms mainly use bioinks to create imitation living tissues. Bioinks must first have very good biological activity, similar to the extracellular matrix environment in the body, which facilitates the further development of printed cells and establishes communication between cells.
At present, there are four main types of bioinks: ion-crosslinking, temperature-sensitive, photosensitive and shear-thinning:
◆ The ionic cross-linking type mainly realizes the curing of the hydrogel through the ionic cross-linking reaction, such as the alginate series ink, when the sodium ion in the sodium alginate is replaced with the calcium ion, the calcium alginate hydrogel is obtained.
◆ Temperature-sensitive ink mainly realizes the transition from sol state to gel state by heating or cooling, such as gelatin ink, when printing, it is necessary to heat the nozzle to melt the gelatin, and cool the bottom printing platform to achieve gelatin setting;
◆ The photosensitive ink mainly uses light to activate the photoinitiator in the ink to realize the transition of the ink from the sol state to the gel state. -GM series) material.
◆ Shear thinning ink mainly uses the phenomenon that the apparent viscosity of some materials decreases with the increase of shear stress. In the sol state, for example, carbomer glue plus GelMA or collagen is used to form bioink.
3. 3D Bioprinting Process
According to the different forming principles and printing materials, biological 3D printing technology can be subdivided into 3DP, SLS, FDM, SLA printing, etc.
4. Applications of 3D Bioprinting
Since 3D bioprinting can not only manufacture structures of specific shapes, but also provide a three-dimensional culture environment for cells, 3D bioprinting has a wide range of applications in the manufacture of tissues and organs. Currently, it is mainly used in cartilage, skin, blood vessels, tumor models and other complex organs. 's print.
5. The future of 3D bioprinting
3D bioprinting is a new technology that combines biomanufacturing and additive manufacturing. It is a multidisciplinary cutting-edge technology such as machinery, materials, biology, and medicine. It provides a new way for research in the field of tissue engineering and regenerative medicine. Currently Bioprinting has made a lot of progress in bioink preparation, printing process research and development, printing equipment development and medical application research, but at present, most of these researches focus on solving manufacturing problems. Functional breakthroughs and applications.
