by Kinjal Parekh

Graphic design by Raymond Zhang

Imagine being a paramedic treating a trauma patient who’s bleeding uncontrollably. Every second feels like a countdown, yet your options are limited. The patient needs platelets to survive, but those lifesaving cells are stored within hospital blood banks, far from the scene of the crisis. Severe hemorrhage is the leading cause of death among trauma patients before they reach the hospital, and it accounts for up to 40% of in-hospital trauma fatalities.¹ Given this reality, what if synthetic platelets were readily available to quickly reach the site of injury and stop bleeding? 

Though this may sound like science fiction, it could soon become a reality, thanks to synthetic platelets which are designed to mimic the wound-healing functions of natural platelet and hold immense potential to transform trauma medicine.² If proven safe and effective, they could one day become a routine treatment for first responders and clinicians to control blood loss and save countless lives.² For now, however, further testing and careful clinical translation remain essential.

The Roles and Limitations of Natural Platelets

Platelets play a critical role in the body’s defense against blood loss. When a blood vessel is injured, they sense the damage, travel to the site, and trigger the coagulation cascade, a chain reaction that forms a stable clot and stops bleeding. Without them, even minor injuries could become fatal.³

The current standard of treatment for severe bleeding is the transfusion of blood products, such as platelets.² While lifesaving, these donated platelets have notable limitations. They have a short shelf life of five days and must be stored at room temperature while constantly being shaken to prevent clumping, making them difficult to transport and maintain.² They can also trigger immune reactions in recipients and carry a risk of bacterial contamination, making them the blood component most frequently associated with transfusion-related sepsis.⁴

These clinical challenges are compounded by supply shortages. In 2022, the American Red Cross declared its first-ever national blood crisis, reporting the worst shortage in over a decade. Hospitals were forced to delay vital transfusions, and platelet donations were in particularly short supply,⁵ underscoring the urgent need for sustainable, alternative ways to manage bleeding emergencies.

Efforts to improve bleeding management have led to several alternative approaches. Recombinant clotting factors, which are lab-produced versions of the body’s natural clotting proteins, can help restore coagulation in certain conditions, but their high cost limits widespread use, particularly in low-resource or emergency settings.⁶ Another option is topical sealants, often used in surgery, which can help control external bleeding by forming a physical barrier over wounds.⁷ However, they are ineffective against internal bleeding, which remains one of the leading causes of preventable death in trauma.⁷ These limitations have driven scientists to explore a new frontier: artificial platelet-mimetic materials that can work with the body’s own repair mechanisms. Such technologies could one day bridge the gap between current treatments and the urgent need for safe, shelf-stable, and rapidly deployable solutions.

The Potential of Synthetic Platelets

A promising advance comes from the lab of Dr. Ashley Brown, an associate professor in the Joint Department of Biomedical Engineering at North Carolina State University and the University of North Carolina at Chapel Hill. Her team has developed platelet-like particles (PLPs), synthetic materials designed to replicate the key behaviours of natural platelets.²

These PLPs are made from ultrasoft hydrogels, which are soft, water-based polymers that can deform and respond dynamically to their environment. What makes them remarkable is their ability to recognize and bind to fibrin, a protein that naturally forms at injury sites to stabilize blood clots. This fibrin-targeting mechanism acts as a biological “homing signal,” guiding the synthetic platelets directly to the wound.⁷ Once attached, the PLPs change shape and contribute to clot retraction, a critical process that pulls the wound edges together and strengthens the clot, just as real platelets do. This helps seal the injury and may also accelerate tissue repair and recovery.⁷

In preclinical studies, these synthetic platelets have shown highly encouraging results. In mouse models of liver injury, PLPs rapidly localized to the site of bleeding and significantly reduced blood loss compared to natural platelet transfusions. Treated animals displayed smaller wounds, more stable clots, and faster recovery. Similar outcomes were observed in rat and pig models, where PLP treatment led to reduced bleeding and effective clot formation.⁷

Importantly, the particles did not accumulate in major organs like the liver, a common concern for nanoparticle-based therapies. Instead, they were safely filtered and cleared by the kidneys within hours. Even in healthy animals without injury, PLPs circulated harmlessly without triggering unwanted clotting elsewhere. This selective, injury-dependent activity is a major step forward in ensuring both safety and precision.⁷

In addition to their safety profile and efficient wound healing, synthetic platelets offer another key benefit: their availability. These platelets can be produced in laboratories, making them readily available to patients regardless of blood type, which is a major advantage in emergencies where time is critical. Because their production does not rely on blood donations, they could help overcome ongoing platelet shortages and ensure a consistent, high-quality supply.⁸

Dr. Ronald Warren, a program director in the Division of Blood Diseases and Resources at the National Heart, Lung, and Blood Institute, explains, “By developing a new generation of treatment options for emergency medicine, this research may help improve patient outcomes while potentially reducing healthcare costs.”²

Dr. Brown’s team is now exploring how best to store these particles. Early findings show they can be freeze-dried, making them ideal for ambulances, military settings, and remote areas, or kept in liquid form for hospital use. With continued refinement and testing, synthetic platelets could soon offer a safe, scalable, and life-saving tool for controlling bleeding.²

Innovation with Caution

While the results are exciting, innovation in medicine always requires careful testing. These synthetic platelets, though impressive, do not yet replicate all the complex functions of natural ones, including how real platelets work together to build and strengthen a clot. So far, they have only been tested in experimental settings, where they were given as a single treatment and not in combination with other therapies. In the future, researchers will need to evaluate how well they work alongside regular platelets or other bleeding treatments, and whether repeated doses are safe and effective.⁷ Most importantly, there have been no in-human clinical trials yet, which is critical for these synthetic platelets to become a reality.⁷ 

Nonetheless, even in these early stages, the potential of synthetic platelets is undeniable. Representing a new generation of trauma care, these engineered particles, with continued research, collaboration, and cautious optimism, could one day become a standard treatment in trauma settings, transforming how we save lives when every second counts. 

References

1.Raykar NP, Makin J, Khajanchi M, et al. Assessing the global burden of hemorrhage: The global blood supply, deficits, and potential solutions. SAGE Open Medicine. 2021 Jan;9:205031212110549.

2. A potential game-changer for emergency medicine: synthetic platelets. National Heart, Lung, and Blood Institute. 2024. Available from: https://www.nhlbi.nih.gov/news/2024/potential-game-changer-emergency-medicine-synthetic-platelets

3. Holinstat M. Normal Platelet Function. Cancer and Metastasis Reviews. 2017 Jun;36(2):195–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5709181/

4. Levy JH, Neal MD, Herman JH. Bacterial contamination of platelets for transfusion: strategies for prevention. Critical Care. 2018 Oct 27;22(1).

5. American Red Cross. Red Cross Declares First-ever Blood Crisis amid Omicron Surge. Redcross.org. 2022. Available from: https://www.redcross.org/about-us/news-and-events/press-release/2022/blood-donors-needed-now-as-omicron-intensifies.html

6. Blankenship C. To manage costs of hemophilia, patients need more than clotting factor. Biotechnology Healthcare. 2008 Nov 1;37–40.

7. Nellenbach K, Mihalko E, Nandi S, et al. Ultrasoft platelet-like particles stop bleeding in rodent and porcine models of trauma. Science translational medicine. 2024 Apr 10;16(742).

8. Synthetic platelets stanch bleeding, promote healing using advanced materials. National Science Foundation. 2024. Available from: https://www.nsf.gov/news/synthetic-platelets-stanch-bleeding-promote-healing.