Organoid technology aims to use 3D culture technology to
mechanisms taste. In fact, listening or not has nothing to do with the ears, and twisting the ears is also an inappropriate corporal punishment for children.
Can I change an obedient ear? In theory, this is possible. With the help of new technologies in the field of organoid research and development, this desire can generally be achieved. You might ask, what are organoids?
Organoids, in a narrow sense, refer to structures formed by the differentiation of animal cytoplasm and possessing the functions of certain animal organs.
Obviously, culturing organoids is one of the core technologies. The researchers cultured the isolated embryonic or pluripotent stem cells on a scaffold made of extracellular matrigel, which is actually a gel-like substance (also called a hydrogel) in which cells can grow for three-dimensional objects.
This technology has relatively high requirements on the medium. It not only needs to have important matrix components such as type IV collagen, laminin, and nestin, but also has high tensile strength. This cultured matrigel generally needs to be stored in a low temperature environment of -80°C to -20°C.
After cells are implanted in cultured matrigel, the signaling pathway between them is roughly the same as the signaling pathway that cells develop and maintain homeostasis in the human body. Therefore, scientists can activate or inhibit specific signaling pathways involved in organoid formation by adding growth factors and small molecules to the culture matrigel. That is, different combinations of additives are used according to the needs of preparing different organoids.
At present, some organoids with some key physiological structures and functions have been successfully cultivated, including liver, brain, intestine, pancreas, prostate, and retina.
So, what are the uses of cultured organoids?
The applications of miniature “organoid”
organoids are vast and their potential is staggering.
Different from the traditional culture of cells in nutrient solution, the organoids cultured in Matrigel contain a variety of cell types, breaking through the pure physical contact between cells, and a closer interaction between cells and matrix, thus forming a Functional “microorgans”.
These micro-organs can better simulate the occurrence process and physiological and pathological states of organ tissues. For example, tiny brain organs could help us explain why people are left-handed or right-handed.
Cultivating a miniature human brain, this seemingly unprecedented “big project” is not difficult for scientists. What’s especially surprising is that they grew their miniature brains out of ordinary skin cells. They first converted these skin cells into stem cells. As the stem cells continue to grow, the brain cells gradually differentiate, then stop the supply of nutrients to the cells, and finally they are implanted in a cultured matrigel and cultured in an incubator.
Now, scientists have found a way to boost the growth of the cerebral cortex, that is, increase the proliferation of neural progenitor cells, which can promote cortical tissue expansion and increased cortical folds in brain organoids.
The finding is significant because the cerebral cortex is thought to underlie the unique intelligence of humans. This means that in the near future, “low IQ” will be saved.
There are about 300,000 patients waiting for organ transplants in China every year, but only about 1/30 of them can get the chance to transplant. In addition to paying high medical expenses, these patients also have to bear problems such as rejection reactions that may occur after surgery and life-long medication.
Cultivated organoids and then transplanted into the human body to repair damaged organs have always been the goal of scientists. However, at the moment we only see hope, and there is still a long way to go before a real transplant.
Among them, the lack of vascular system in organoids is a major problem. As we all know, blood vessels are an important structure for organ growth and development to obtain energy. Without this system, organoids cannot survive in humans. In addition to blood vessels, scientists have been unable to make organoids have connective tissue and an immune system.
However, scientists abroad have transplanted liver and small intestine organoids into experimental mice. These organoids did their job in a short period of time. This is already a huge improvement.
In addition, some scientists transplanted the micro-tissues cultured by organoid technology into the body of premature infants, hoping to grow a gut-like in the body to treat intestinal damage caused by infection.
Experts predict that in 10 years, there will be a qualitative breakthrough in organoid human transplantation technology.
Cancer has long been a major threat to human health, caused by genetic mutations that cause certain cells in the body to proliferate uncontrollably.
Doctors have found in clinical treatment that each cancer cell is different even if it occurs in the same organ. They consist of a mixture of cells that carry different mutations that determine the ultimate effect of the treatment. Cultivating malignant tumor cells, conducting anti-cancer drug screening, and finally determining which drug to use is the key to treating cancer.
In the past, doctors have typically grown 2D cell lines of malignant tumors in petri dishes, or have done so in mouse models. However, 2D cell culture is not the natural state of cell growth, and thus gene expression, signaling, and morphology may all differ from natural cells. Mouse models are not only time- and resource-intensive, but also have very different pathways from human cancers.
The application of organoid technology can more closely replicate some of the key properties of the primary tumor, while also saving time and resources than mouse models. In short, it helps doctors find the right cancer drug faster and more accurately. Although it may not cure the disease, it can at least improve clinical outcomes, that is, prolong life.
At present, it is difficult to print “organoids”
organoid culture technology above the millimeter scale, that is, it cannot reach the size of organs in the human body, which limits its application in regenerative medicine and other fields. The biological 3D printing technology can realize the precise spatial arrangement of cells and biological materials, but it cannot make the cell tissue achieve macroscopic arrangement by itself, that is, it cannot grow by itself.
Therefore, if these two technologies can be combined, it is possible to obtain highly simulated organ products. In theory, this is a bioprinted product based on microscopy technology.
It works roughly by aspirating the cells and depositing them precisely inside the precursor of the culture matrix glue liquid, and then controlling the final cell density by adjusting the nozzle size, flow rate and printing speed. After the first printed cell culture has developed a certain shape and function, it is put back into the printer for a second printing, that is, printing a second cell tissue around the already developed cell tissue.
In this way, scientists can finally precisely control the development of the printed cell tissue.
There is no doubt that printing organoids is a very complex and difficult technology, involving expertise and cutting-edge technologies in medicine, imaging, physics, and biology.
Currently, the technology for printing organoids is still in the laboratory stage. However, some scientists have poured cold water on it. They warn that organs made with limited technology cannot interface with infinitely complex human systems unless absolutely necessary, because we don’t know what the side effects will be if implanted.
In conclusion, scientific research is a complex practice that is both challenging and risky.
Organoid technology aims to use 3D culture technology to