Synthetic Blood Cells: A New Frontier in Medicine
- MedReport Foundation
- 18 hours ago
- 5 min read
Blood is a limited and highly valuable resource. Blood donations and transfusions
are routinely practiced for sustaining human health and welfare. However,
hemorrhage is still a global cause of death estimated at 1.9 million per year (1).
Scientists are working on new ways to increase the blood supply, from growing
blood in the laboratory to synthetic blood alternatives (2, 3, 4). But before we
explore these solutions, we need to understand what blood is, and why it is a
limited resource.
What exactly is blood?
Blood is a special and complex fluid in your body. It connects all your organs and
keeps them working. It carries oxygen, nutrients, and waste products throughout
the body (5). Blood has four main components. Half of it is plasma, made of a
mixture of water, sugar, fat, and protein. Its main function is to transport nutrients,
hormones, and blood cells through the body. The other half of the blood consists
of red blood cells (called erythrocytes), which are the bright red, donut-shaped
cells that give blood its characteristic color. This red color comes from a special
protein called hemoglobin, which is very abundant in each red blood cell, and
whose main function is to carry oxygen from the lungs to the rest of the body, and
to return carbon dioxide to the lungs for exhalation. The remaining small fraction
of the blood is made of white blood cells (leukocytes), which protect the body
from infections, and platelets, which are made of small cell fragments that help
on the blood clotting (coagulation) process by gathering all together at the site of
an injury (6).
Why is blood a limited resource?
Blood transfusions save lives. People need them during cancer treatment,
surgeries, or after accidents. However, supplies run short in hospitals during
holidays, natural disasters, or pandemics. There are even places with limited
donors where blood is not available at times of need. And there are situations like
emergencies where doctors need to quickly match the patient’s blood type before
making a transfusion. This process can take time and delay treatment when every
second matters (7).
Even more, before a transfusion can be made, the donated blood needs to pass
screening checks before it is eligible for a patient. First, it needs to be free of
infections and viruses (for example HIV, hepatitis B, etc.). Second, the patient
needs to be the same blood type as the donor (A, B, O, AB, positive or negative)
and note that some blood types are more common than others. And finally, the
blood needs to be fresh and well-preserved (7). Blood from donors can only be
preserved and still used for transfusions for up to six weeks according to U.S.,
Australia, and EU regulations. There are even more strict countries like Japan in
which blood can only be stored for three weeks. This means that some blood
bags expire before someone can benefit from them (8).
How to overcome limited blood supplies?
As we already know, blood is a complex body tissue. Many efforts are being made
to increase the blood supplies that the world needs. Some laboratories are
manufacturing blood from scratch, from donated adult human stem cells (body’s
master cells that can generate new cell types). This process is still costly and
time-consuming, although we might see improvements soon, as this approach
has already been tested in healthy humans (2, 3, 4). There are other alternatives
that are being explored, like synthetic blood cells, which we will cover in the next
section.
Synthetic Blood Cells, what are they and do they work?
After numerous attempts, a group of scientists from Japan finally found the key
to transforming expired human blood from donors into lab-made oxygen carriers
that emulate red blood cells. This is what we call synthetic blood (9).
Synthetic blood cells are made by isolating and purifying hemoglobin (the most
abundant protein in red blood cells) and packing hemoglobin inside tiny fat
bubbles (liposomes), which are then called hemoglobin vesicles. Because free
hemoglobin can be harmful to the human body (10), its toxicity is shielded by
liposomal encapsulation, mimicking the red blood cell’s structure. These
mimicked cells are finally deoxygenated for long-term storage (11). Because the
hemoglobin is preserved encapsulated, it becomes stable and functional over a
long period of time. In fact, this synthetic blood can be stored for over two years
at room temperature, making it ideal to solve blood supply problems in isolated
regions, military medicine, and medical emergencies during natural disasters.
Moreover, this synthetic blood works for everyone (it has universal compatibility).
It does not depend on blood type (A, B, O, AB, positive or negative), so it can be
given to any patient. It is also free of viruses, and it has a low risk of immune
reactions because it does not contain white blood cells.
What therapeutic uses does synthetic blood have?
Synthetic blood has been proved safe to use in preclinical studies, as it has
stopped hemorrhages from mice and dogs without negative immunological
reactions (9). It has also been successfully tested as an alternative for blood
transfusion and oxygen carrier in healthy humans. New clinical trials with higher
doses are already being conducted in humans (12).
Deoxygenated hemoglobin vesicles (synthetic blood) might also be promising for
targeted tumor therapy, ischemic strokes and cardiovascular event mitigation,
because deoxygenated hemoglobin naturally accumulates where oxygen is low
(like happens in tumors and strokes). Another promising aspect is that the lipidic
capsules can be modified, making them specially targeted for anti-inflammatory
or antioxidative treatments (9). We will have to wait for new clinical outcomes to
see if synthetic blood can meet our welfare needs.
References
1. Cannon JW. Hemorrhagic shock. N Engl J Med. 2018;378(4):370-9.
doi:10.1056/NEJMe1805705
2. Kutikuppala LVS, Ponnaganti SVK, Kale SSS, Kode R, Kuchana SK.
Transfusions with lab-grown red blood cells: a new development in
science. Exp Hematol. 2023; doi:10.1016/j.exphem.2023.01.004
3. Dufour S. Blood factories: the future of transfusions [Internet]. MedReport;
[cited 2026 Apr 06]. Available from:
transfusions
4. Jassal S. Lab-grown blood: the future of transfusions [Internet].
MedReport; [cited 2026 Apr 06]. Available from:
transfusions
5. Weatherholt AM, Fuchs RK, Warden SJ. Specialized connective tissue:
bone, the structural framework of the upper extremity. J Hand Ther. 2012
Apr-Jun;25(2):123-31.
6. American Society of Hematology. Blood basics [Internet]. Washington
(DC): American Society of Hematology; [cited 2026 Apr 06]. Available
7. World Health Organization. Blood safety and availability [Internet].
Ginebra: WHO; [cited 2026 Apr 06]. Available from:
availability
8. Chang TMS, Bulow L, Jahr J, Sakai H, Yang C. Nanobiotherapeutic based
blood substitutes. Singapore: World Scientific Publishing Co. Pte. Ltd;
2022.
9. Sakai H, Kobayashi N, Kure T, Okuda C. Translational research of
hemoglobin vesicles as a transfusion alternative. Curr Med Chem.
2022;29(3):591-606. doi:10.2174/0929867328666210412130035.
(Source for illustration figure, adapted)
10. Vallelian F, Buehler PW, Schaer DJ. Hemolysis, free hemoglobin toxicity,
and scavenger protein therapeutics. Blood. 2022 Oct 27;140(17):1837-
1844. doi:10.1182/blood.2022015596
11. Kure T, Sakai H. Preparation of artificial red blood cells (hemoglobin
vesicles) using the rotation-revolution mixer for high encapsulation
efficiency. ACS Biomater Sci Eng. 2021;7(6):2835-44.
doi:10.1021/acsbiomaterials.1c00424
12. Azuma H, Amano T, Kamiyama N, Takehara N, Jingu M, Takagi H, et al.
First-in-human phase 1 trial of hemoglobin vesicles as artificial red blood
cells developed for use as a transfusion alternative. Blood Adv.
2022;6(21):5711-5. doi:10.1182/bloodadvances.2022007977
Illustration adapted from (9) and from image by Artster Design (ID:
2539656441), Shutterstock.
