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Blood reserves are in short supply around the world. According to the World Health Organization (WHO), blood donation services in many countries are simply unable to meet demands for collecting and storing healthy blood. Germany's Red Cross (DRK) estimates that some 112 million annual donations are required to cover the need. The DRK adds that one blood donation can be enough to help up to three injured or extremely ill patients.
Blood donations, however, vary greatly according to national wealth, with 40% of 118.5 million annual donations coming from high-income countries that make up only 16% of the world's population.
Yet, even wealthy countries constantly need to draw from and replenish their blood banks. Germany alone uses some 15,000 units of blood each day. Often, even promises of money, gifts or vouchers are not enough to encourage donor participation.
Animal blood not (yet) an alternative
Although animal blood could theoretically be used in human transfusions if successfully altered with the use of gene-editing technology, the impediments to getting there are incredibly complex. Animal blood cells are significantly different from human blood cells, especially regarding surface structure.
The human immune system would immediately recognize non-altered animal blood cells as foreign and reject them. That is why all immune-related antigens would have to be removed or human antigens added, a highly complicated procedure. These issues have rendered the potential use of animal blood for human transfusions unrealistic in the near future.
The quest to create a new, universal blood type
At the moment, different approaches to finding a solution to blood shortages are being taken by scientists around the world. Researchers have, for instance, altered blood stem cells, also known as hematopoietic stem cells or HSCs, in ways that allow them to transport more oxygen. They have developed enzymes to neutralize blood type, doing away with the problem of compatibility. Artificial, longer-lasting red blood cells are being developed, too.
But the promise of blood substitutes also comes with considerable risk. Such blood can trigger potentially deadly anaphylactic reactions when, for example, the immune system recognizes foreign enzymes or elements contained in artificial blood. Any such blood substitute must replicate all of the functions of biological blood and be universally compatible — similar to naturally occurring Type O blood, which is considered a "universal donor" type.
What is your blood made of? Where is it formed?
The most promising research approaches so far
Several methods for producing lab-made blood are nearly ready for use; others need more trials, including human testing, to ensure such new blood products are safe. Here, a list of five top prospects:
1. Genetically modifying red blood cells
Researchers at Stanford University and the University of California San Francisco (UCSF) have used CRISPR gene-editing technology to develop a new method for altering bone marrow stem cells in a way that increases their production of hemoglobin in red blood cells, allowing these to carry more oxygen.
So far, returns have been modest when compared to biological blood, with researchers only producing roughly 1% of the hemoglobin that a donor would. Still, when the team's trial was completed with no complications or side-effects to participants, it was celebrated as a medical breakthrough.
2. Neutralizing blood type with gut bacteria enzymes
In Denmark and Sweden, scientists have found an enzyme in intestinal bacteria that can remove particular elements from blood cells, namely the ABO blood type antigens that determine the different biological blood groups, among them A and B. When these determiners are removed, blood cells become Type O, meaning they can be used for almost every possible patient.
Still, until now scientists have been unable to remove the determiners in their entirety, leaving small traces behind and thus posing a risk of allergic reaction in some individuals. Another major hurdle is the removal of the so-called rhesus factor — a surface protein key in determining blood compatibility.
3. Nano RBCs: Microscopic artificial blood cells
Researchers at Penn State University in the US are currently producing tiny, artificial red blood cells (RBC) that function just like the real thing. Although nano-RBCs are only one-tenth the size of normal blood cells they can transport just as much oxygen. These little cells are extremely flexible and can even move through small blood vessels. They would also seem ideally suited for emergency situations and natural catastrophes as they can be stored at room temperature for long periods of time.
4. Military application for enhanced performance
The US military is backing research that loads up red blood cells with special nanoparticles. The Pentagon's Defense Advanced Research Projects Agency, better known as DARPA, is creating what it calls a "Red Blood Cell Factory" that will help soldiers cope with lack of oxygen at altitude, in extreme heat or cold, and when affected by pathogens or endemic illnesses such as malaria. China is reportedly conducting similar research.
5. Using blood banks to create a universal donor blood
Researchers at Japan's Nara Medical University began testing artificial hemoglobin in humans in March 2025. Scientists there are harvesting hemoglobin from unused blood bank reserves. They are efficient in transporting oxygen and can be used with any blood type. Initial data was published in the June issue of the Journal of Artificial Organs. The report said that some test persons developed a slight fever but that the results were so promising that researchers are hoping to make the method available for use by 2030.
All of these approaches are being pursued at great pace. Yet, it will still be years before safe artificial blood can be produced at scale.
Until then, human blood donations remain essential for transfusions to continue.
This article was originally written in German and translated by Jon Shelton.
