Unexplainable: The Real Quest for Fake Blood

Episode Release Date: April 23, 2025

Introduction: The Unsung Hero of Blood Donation

The episode opens with Noam Hassenfeld recounting the remarkable story of James Harrison, an 88-year-old who quietly saved nearly two and a half million lives through his extraordinary blood donations. Harrison, a humble railway clerk, possessed a rare antibody in his blood that was pivotal in creating a medication saving countless babies worldwide. Despite his fear of needles and the demanding schedule of over 1,200 donations spanning 64 years, Harrison's unwavering commitment underscores the critical yet often overlooked role of blood donors.

Understanding the Complexity of Blood

Nikki Twilley, a science writer, delves into the multifaceted nature of blood, highlighting its crucial roles:

• Oxygen Transport: "Picking up oxygen in the lungs and releasing it around the body" [04:32].
• Nutrient Delivery and Waste Removal: Transporting hormones and eliminating toxins like carbon dioxide and urea.
• Regulatory Functions: Maintaining body temperature, pH balance, and chemical homeostasis.
• Immune Defense: Serving as the body's first line of defense against pathogens and toxins.

Twilley emphasizes, "Blood is alive. It's filled with cells that are doing things, and it's very hard to keep it alive outside the body" [03:56]. This complexity makes replicating blood a formidable scientific challenge.

The Quest for Synthetic Blood

The discussion shifts to contemporary efforts to create artificial blood. Dr. Alan Doctor, leading a $46 million DARPA-funded initiative, is at the forefront of this research. Twilley explains Dr. Doctor’s innovative approach to synthesizing red blood cells:

"It's a fatty synthetic shell that is jammed full of hemoglobin, which is an iron-rich protein that picks up oxygen in your lungs, carries it safely around the body, and releases it" [07:04]. The challenge lies in replicating the dynamic nature of hemoglobin, which in the body is aided by enzymes to release oxygen effectively. Despite the ingenuity of Dr. Doctor's method, replicating this biological process synthetically remains elusive.

Historical Hurdles: The Hbox Failures

Twilley recounts the history of synthetic blood development, highlighting the notorious Hbox (Hemoglobin-Based Oxygen Carriers) trials during the AIDS crisis:

"They were on the verge of success... but it was a complete flop. People were like, ‘I guess we really can't make a synthetic blood. It's too complicated for us’" [11:34]. One such trial by Baxter Pharmaceuticals resulted in a tragic outcome where 24 out of 52 patients died, leading to the project's termination by the FDA [12:15]. This failure cast a long shadow over the field, illustrating the profound risks and complexities involved in creating safe synthetic blood alternatives.

Lab-Grown Blood: A Promising Avenue

Shifting focus, Twilley explores the burgeoning field of lab-grown blood, which leverages human embryonic stem cells to cultivate red blood cells in controlled environments.

"Once you tell the stem cell that it wants to be a red blood cell, it knows how to do oxygen delivery" [18:03]. Despite the potential, current production methods are prohibitively expensive and yield minimal quantities—only about 8ml per culture at a staggering cost of $75,000 per syringe [19:10]. However, the UK's National Health Service has initiated trials injecting lab-grown blood into healthy humans, showing promising early results with no immediate side effects [19:38].

Current Trials and Future Prospects

In the UK trials, participants have received lab-grown blood with encouraging outcomes. Twilley observes, "There have been no side effects at all" [20:38], though rigorous long-term studies are ongoing to evaluate the longevity and compatibility of these synthetic cells within the human body.

Dr. Doctor reflects on the potential impacts, comparing the innovation to the revolutionary advances seen with mRNA vaccines:

"I think, you know, I went in the skeptic. I came out thinking, well, this is not going to be saving your life anytime soon... it might down the line actually get there" [22:59]. The research hints at broader therapeutic applications, such as delivering drugs within red blood cells without triggering immune responses, potentially transforming future medical treatments.

Conclusion: A Balance of Skepticism and Hope

The episode culminates with a nuanced perspective on the future of synthetic and lab-grown blood. While acknowledging the significant hurdles and historical setbacks, Twilley remains cautiously optimistic about the long-term benefits and scientific advancements spurred by this research:

"I fully believe humans can get there one day, but it's a complicated project" [13:31]. The ongoing efforts not only aim to solve the immediate crisis of blood shortages but also pave the way for groundbreaking medical therapies beyond the realm of transfusions.

Key Takeaways:

• James Harrison's Legacy: A testament to the life-saving impact of blood donors.
• Blood’s Multifaceted Roles: Critical for oxygen transport, waste removal, regulation, and immune defense.
• Synthetic Blood Challenges: Replicating the complex functionality of natural blood remains difficult.
• Historical Lessons: Past failures like the Hbox trials highlight the risks and intricacies involved.
• Lab-Grown Blood Advances: Promising trials in the UK indicate potential, despite current limitations in scalability and cost.
• Future Implications: Beyond transfusions, synthetic blood research could revolutionize drug delivery and other medical treatments.

This episode of Unexplainable meticulously unpacks the intricate journey towards creating artificial blood, blending human stories with scientific exploration to illuminate a quest that bridges the known and the unknown.

Notable Quotes:

• "Blood is alive. It's filled with cells that are doing things, and it's very hard to keep it alive outside the body." – Nikki Twilley [03:56]
• "What if we could just make it ourselves?" – Noam Hassenfeld [02:26]
• "I fully believe humans can get there one day, but it's a complicated project." – Nikki Twilley [13:31]
• "It's like we can't help being entranced by blood." – Noam Hassenfeld [15:19]

Credits: Produced by Noam Hassenfeld with contributions from Nikki Twilley and Alan Doctor. Special thanks to the Unexplainable team: Jorge (editing), Christian Ayala (sound design), Thomas Liu (production support), and Melissa Hirsch (fact-checking).