According to the World Health Organization (WHO), blood transfusion services in many countries face the challenge of providing enough blood. According to the German Red Cross (DRK), around 112 million blood donations are needed worldwide every year. According to the DRK, one donation can help three injured or seriously ill people.
However, blood donors are not evenly distributed: 40 percent of donors come from high-income countries, even though these countries are home to only 16 percent of the world's population. In addition, blood supplies from Europe are not usually exported, for example to Africa or Asia.
Even in countries with high GDPs, there is a constant need for blood. Often, neither monetary compensation nor attractive gifts or vouchers are enough to motivate enough people to donate blood. In Germany alone, around 15.000 bottles of blood are needed every day.
Animal blood is (still) not an alternative
The idea of genetically modifying animal blood so that it can be used for transfusions in humans is theoretically possible, but the process faces major challenges. Namely, animal red blood cells differ significantly from human ones, especially in their surface structure.
The human immune system would normally recognize animal blood as foreign and reject it. Therefore, all immunologically relevant antigens would have to be removed or replaced with human antigens – which is very complicated. Therefore, the use of animal blood for transfusions in humans is currently still unrealistic.
The search for universal artificial blood
In search of alternatives, scientists around the world are developing different approaches to create artificial blood. For example, they are modifying blood stem cells so that red blood cells can carry more oxygen. They are also developing enzymes that can neutralize blood types so that blood can be universally used. In addition, artificial red blood cells are being developed that have a longer shelf life.
However, the development of artificial blood also carries certain risks. Immunological reactions can occur if the body reacts to foreign enzymes or components of the artificial blood with anaphylactic – i.e. life-threatening – reactions. Artificial blood must therefore fulfill all the functions of natural blood and be universally applicable.
The most promising research approaches
Some methods for producing artificial blood are already almost ready for use, while others require additional testing, including human experiments, to ensure they are safe.
1. Genetic modifications of red blood cells
Scientists at Stanford University and the University of California, San Francisco (UCSF) have developed a new method using CRISPR technology to modify certain stem cells in bone marrow to produce more hemoglobin, a red blood pigment. This allows red blood cells to carry more oxygen. However, so far, the method can only produce very small amounts, about one percent of a blood donation. Since there were no complications or side effects, the results are considered a medical breakthrough.
2. Neutralization of blood groups by enzymes from intestinal bacteria
Scientists from Denmark and Sweden have found enzymes from intestinal bacteria that can remove certain substances from the surface of red blood cells. These substances determine the blood type – for example, A or B. When they are removed, the blood cells become type 0, which can be given to almost anyone. However, small traces of these substances still remain, which can cause severe allergic reactions in some people. Another major challenge is removing the so-called Rhesus factor.
3. Nano-red blood cells: small artificial blood cells
Scientists at Penn State University in the United States are developing tiny, artificial red blood cells (RBCs) that function just like real ones. Although these nanoparticles are ten times smaller than natural ones, they can carry the same amount of oxygen. They are very flexible and can pass through even the narrowest blood vessels. Because they can survive at room temperature for long periods of time, they are ideal for emergencies and disasters.
However, artificial blood cells must not cause clotting, thrombosis or immunological reactions. It is also not yet possible to produce sufficient quantities of these cells in the laboratory. Therefore, their safety and effectiveness on a large scale cannot yet be confirmed.
4. Military use to increase endurance
The US military is supporting research in which natural red blood cells are enriched with special nanoparticles. The DARPA (Defense Advanced Research Projects Agency) research program, called the "Red Blood Cell Factory", is supposed to help soldiers cope better with low oxygen levels - for example, at high altitudes, in extreme temperatures, with great physical exertion or with infections such as malaria. Similar research is reportedly being conducted in China.
5. Universal blood from old stocks
In Japan, researchers at Nara Medical University have been testing artificial hemoglobin bubbles on humans since March 2025. The bubbles are made from old, unused blood supplies. They are able to transport oxygen efficiently and are compatible with all blood types. The first results were published in June 2025 in the Journal of Artificial Organs. Some of the subjects had mild fevers, but the results are so promising that the researchers plan to seek approval for the method by 2030.
These are promising approaches that are being intensively developed. However, it will be several more years before artificial blood is available in sufficient quantities and with the necessary degree of safety for widespread use.
Until then, voluntary blood donation remains indispensable in transfusion medicine.
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