Minimal Artificial Body
Introduction
We want to live longer, but what defines "we"? Most agree that the essence of self is the mind which is rooted in the brain, so extending the life of the brain equates to extending life itself. This implies that if brain function can be preserved, the rest of the body is disposable. Aging deteriorates our bodies to a point where they can no longer adequately support the brain. This raises a question: Is it more feasible to repair the damage incurred by aging, or to create an alternative means of sustaining the brain?
The answer depends on various factors and remains uncertain. While much research has focused on combating aging, there is little exploration into bypassing aging through artificial means. In a previous post, I described strategies to bypass aging with various replacement strategies. The current discussion aims to conceptualize one such strategy, the simplest possible life-support system capable of maintaining the functions of a human brain or head outside a complete biological body, in a way that is long term and scalable. I term this hypothetical system the Minimal Artificial Body (MAB).
To design an MAB, we must consider the brain's essential physiological needs and their potential artificial replacements. It may be more practical to preserve the entire head rather than just the brain, as the head houses critical sensory organs and supports vital functions without significantly increasing complexity. There is little to no added mortality risk for retaining the brain, because no death is caused by head but not brain-related issues.
Developing an MAB would require an integrated approach, combining robotics, sensors, fluid management systems, and recombinant DNA technology. While future advancements might allow us to create artificial bodies vastly superior to our biological ones, the pressing nature of aging necessitates a minimal solution first.
If successfully implemented, such a system could benefit not only individuals in advanced ages whose bodies are failing, but also individuals with terminal systemic diseases like metastatic cancer, or victims of traumatic injuries that compromise the body beyond repair.
Note that for the purpose of this exercise, I am disregarding the intrinsic aging of the brain. While an MAB could potentially sustain the brain longer than a biological body, achieving open-ended longevity would ultimately require also addressing the intrinsic aging of the brain itself.
High level description of an MAB
An MAB is designed to support and sustain the human head independently from the rest of the body, maintaining vital functions and neuronal activity. The core of the system is a perfusion device that circulates a nutrient- and oxygen-rich perfusate (a blood analog) through the brain and head, replicating natural circulatory processes to ensure homeostasis.
The MAB is equipped with sensors and electronic systems that continuously monitor and regulate key parameters such as nutrient concentrations, oxygen levels, pH, and temperature. These systems operate in real-time to adjust the perfusate composition, ensuring the brain receives precisely what it needs to maintain optimal function.
Essential elements like synthetic red blood cells for oxygen transport and other plasma components are supplied via a controlled feed. Electrical power sustains the MAB’s operation, powering its monitoring, regulation, and support systems. A built-in computer interface allows for user interaction and control, enabling communication between the person and external devices.
For mobility, the MAB is equipped with wheels and a robotic arm, enabling movement and autonomous transport. This design allows the system to function in various environments, maintaining adaptability while ensuring continuous operation and user interaction.
In what follows, I will provide a more detailed and comprehensive (naturally still very rough of course) description of an MAB, covering everything from the systems responsible for nutrient delivery, waste removal, and temperature regulation, to the mechanisms for maintaining circulation, sensory input, and immune protection. The aim is to fully articulate the general design and functionality of an MAB and demonstrate its relative feasibility.
Detailed description of an MAB
Blood plasma
Role: This is the liquid component of blood. It's mostly water (about 90%) and contains various substances like proteins, electrolytes, nutrients, hormones, and waste products. Let’s go over all of them.
Glucose and carbohydrates
Role: Primary energy source for cells.
Natural source: Dietary carbohydrates processed by the digestive system and absorbed into the blood.
Arteficial alternative
Production
Extraction from Starch: Carbohydrates like starch can be broken down into glucose using enzymatic hydrolysis. Enzymes such as alpha-amylase and glucoamylase efficiently convert starch from sources like corn or potatoes into D-glucose (dextrose).
Synthesis: May also be synthesized chemically through various processes, like fermentation using microorganisms.
Storage and stability: As stable powder, and reconstituted in sterile water on demand.
Amino Acids
Role: Building blocks for proteins, crucial for cell structure, function, and repair.
Natural source: Dietary proteins.
Artificial alternative
Production methods
Extraction: From protein-rich organic sources like soy, wheat, or animal proteins through enzymatic hydrolysis, breaking down the proteins into their constituent amino acids.
Synthesis: Chemical synthesis using methods such as Strecker synthesis or enzymatic catalysis.
Storage and stability: As stable powder.
Fatty Acids
Role: Essential for cell membranes and energy storage.
Natural source: Dietary fats.
Artificial alternative
Production methods
Extraction: From plant oils (e.g., flaxseed, soybean, or fish oil) through cold-pressing or solvent extraction, focusing on essential fatty acids like omega-3 and omega-6.
Synthesis: Processes like Fischer esterification or other organic synthesis techniques.
Storage and delivery: As concentrated liquids to maintain their integrity and prevent oxidation.
Vitamins
Role: Necessary for various biochemical reactions and cellular functions.
Natural source: Obtained from a balanced diet.
Artificial alternative
Production methods
Extraction: From natural sources like fruits, vegetables, or animal products using solvent extraction or pressing methods.
Synthesis: Many vitamins are also synthesized chemically, such as Vitamin C via the Reichstein process, or organically, like B-complex vitamins through microbial fermentation.
Storage and stability: Stable liquid or powder forms.
Minerals and electrolytes
Role: Essential for numerous physiological processes, including nerve function, muscle contraction, hydration, enzyme activity, and structural support.
Natural source: Inorganic elements derived from a balanced diet.
Artificial alternative
Production methods
Extraction: Minerals and electrolytes like calcium, sodium, potassium, magnesium, iron, and zinc can be derived from natural mineral deposits, plants, and other organic sources. They are then purified to achieve the required bioavailability and stability.
Synthesis: Some can be synthesized or chemically refined to ensure the necessary purity and bioavailability for specific uses.
Storage and delivery: Stored in a stable, purified form and dissolved in sterile solutions before delivery to prevent any chemical reactions or crystallization.
Essential plasma proteins
Role: Blood-borne proteins produced outside the brain that are crucial for its survival and function. These include signaling molecules that regulate physiological processes such as mood, sleep, appetite, and stress by enabling communication between neurons and other cells; transport proteins that facilitate the movement of essential nutrients, hormones, and ions into and out of cells; enzymes that catalyze biochemical reactions vital for cellular function and metabolism; and additional proteins that support various other critical functions within the brain.
Natural source: Produced by cells in various organs and glands, such as the liver and thyroid glan.
Artificial alternative
Biological production
Recombinant DNA technology: This involves inserting the gene responsible for producing a specific protein into bacterial, yeast, or mammalian cells, which then produce it in large quantities.
Gene cloning: The gene encoding the signaling molecule is isolated and cloned into a plasmid vector.
Expression systems: The plasmid is introduced into an appropriate host cell (e.g., E. coli, yeast, CHO cells), which expresses the gene and produces the signaling molecule.
Purification: The produced molecule is purified using techniques such as chromatography to ensure high purity and activity.
Examples
Insulin: Produced using recombinant E. coli for diabetes treatment.
Erythropoietin: Produced in CHO cells to treat anemia.
Human growth hormone (HGH): Produced using recombinant E. coli for growth hormone deficiencies.
Thyroid hormones (T3 and T4): Produced in yeast cells for hypothyroidism treatment.
Melatonin: Produced using recombinant yeast for sleep disorders.
Microbial Fermentation: Use bioreactors to produce in scale.
Chemical synthesis: Some components can be chemically synthesized, like cortisol is for immunosuppressive treatments.
Storage: Lyophilization (freeze-drying). Teleflex is the primary company working on freeze-dried plasma technology, in collaboration with the U.S. Army. As of 2023, in late-stage development and undergoing clinical trials.
Exhaustive list of factors: Identifying all the essential plasma factors and determining their optimal concentrations will require more extensive literature review and likely additional empirical studies. One study suggest up to 700 unique proteins. Here is a preliminary list:
Hormones and growth factors
Melatonin: Produced by the pineal gland, regulates sleep-wake cycles.
Cortisol: Secreted by the adrenal glands, involved in stress response.
Insulin: Produced by the pancreas, regulates glucose levels.
Thyroid hormones (T3 and T4): Produced by the thyroid gland, regulate metabolism.
IGF-1 (Insulin-like Growth Factor 1): Supports brain development and repair.
Erythropoietin (EPO): Produced by the kidneys, crucial for oxygen delivery.
Transport proteins
Transferrin: Transports iron to cells.
Ceruloplasmin: Transports copper and has oxidase activity.
Albumin: Maintains oncotic pressure, transports hormones, vitamins, drugs, and waste products, and acts as a pH buffer.
Lipoproteins (HDL, LDL): Transport cholesterol and triglycerides.
Thyroxine-binding globulin: Transports thyroid hormones.
Retinol-binding Protein: Transports vitamin A (retinol).
Transthyretin (TTR): Transports thyroxine (T4) and retinol-binding protein with retinol.
Haptoglobin: Binds free hemoglobin to prevent oxidative damage.
Corticosteroid-binding globulin (CBG): Binds and transports cortisol.
Sex hormone-binding globulin (SHBG): Transports and regulates sex hormones like testosterone and estradiol.
Enzymes
Alpha-1 antitrypsin: Protects tissues from enzymes released during inflammation.
Cholinesterase: Breaks down acetylcholine, a neurotransmitter.
Alkaline phosphatase: Involved in dephosphorylation processes that are essential for various metabolic pathways in the brain.
Immunomodulatory proteins
C-Reactive protein (CRP): Plays a role in neuroinflammation.
Alpha-1 acid glycoprotein: Immunomodulatory functions.
Beta-2 microglobulin: Involved in immune response and helps in maintaining cellular immunity.
Coagulation factors: In a closed MAB system, with no risk of injury, we can omit the entire coagulation cascade. This includes both clotting factors and anti-coagulants, significantly simplifying our synthetic blood composition.
Essential metabolites
Role: Metabolites are crucial small molecules that serve as the intermediates and products of cellular metabolism, playing essential roles in maintaining brain function and survival. These include energy sources necessary for sustaining neuronal activity, precursors for neurotransmitter synthesis, and key molecules involved in cell signaling and membrane structure. Unlike plasma proteins, which are macromolecules involved in structural and functional roles, metabolites are generally smaller and more diverse in function, directly fueling the biochemical processes that sustain life.
Natural source: Metabolites can be synthesized by various organs, such as liver and muscles, from nutrients absorbed through the diet, or produced directly by metabolic processes.
Artificial alternative
Extraction: Many essential metabolites can be extracted from natural sources, such as glucose from starch or amino acids from protein-rich foods, through processes like enzymatic hydrolysis and fermentation.
Chemical Synthesis: Some metabolites can be synthesized chemically.
Storage and stability: Stable powders or concentrated solutions.
Exhaustive list of metabolites: Identifying all essential metabolites and their optimal concentrations will require extensive literature review and empirical studies. The following is a preliminary list:
Lactate: Utilized by neurons as an energy source.
Tryptophan: Precursor for serotonin.
Tyrosine: Precursor for dopamine, norepinephrine, and epinephrine.
Acetate: Provides acetyl-CoA for energy production and neurotransmitter synthesis.
Glutamine: Precursor to glutamate, a key neurotransmitter.
Water
Role: Vital for all cellular activities. Acts as a solvent, facilitating biochemical reactions.
Natural source: Drinking.
Artificial alternative: Purified through filtration and distillation methods.
Whole plasma extraction
Source: Plasma can be extracted in scale from farm animals like cows, pigs, or sheep to provide essential nutrients, proteins, and hormones.
Compatibility challenges: Plasma from farm animals contains species-specific proteins and molecules that may not function optimally in human physiology. Even with only microglia present in the MAB, these compatibility issues could lead to dysfunction or toxicity.
Purification Requirements: To mitigate risks, the extracted plasma would need to undergo extensive purification. Advanced techniques like affinity chromatography could be used to isolate essential components and remove potentially harmful proteins, allergens, and pathogens.
Oxygen transport
Role: Oxygen transport is crucial for cellular respiration, where oxygen is delivered to tissues and cells to enable energy production via the electron transport chain in mitochondria.
Natural process: Red blood cells (RBCs), or erythrocytes, are the primary carriers of oxygen in the body. RBCs are produced in the bone marrow via hematopoiesis. Each RBC contains hemoglobin, a protein with four heme groups capable of binding oxygen molecules in the lungs. Hemoglobin releases oxygen in tissues with lower oxygen tension, regulated by factors like pH, temperature, and partial pressures of oxygen (pO2). RBCs also help in CO2 transport and pH buffering via carbonic anhydrase activity.
Artificial Alternative
Synthetic Hemoglobin (Free Hemoglobin Strategies): Free hemoglobin-based systems involve using purified or recombinant hemoglobin that is chemically modified to remain stable outside of red blood cells. These hemoglobin molecules are designed to bind and release oxygen in a similar manner to natural hemoglobin but without the need for a cellular structure. Key approaches include:
Polymerized or Pegylated Hemoglobin: Modifications to prevent renal toxicity and extend circulation time.
Cross-Linking: Chemically cross-linked hemoglobin prevents dissociation into subunits and improves stability.
These methods offer universal compatibility, scalability, and long storage potential. However, they present challenges such as short half-life in circulation, risks of oxidative stress, and potential vasoconstriction due to free hemoglobin interacting with endothelial NO pathways.
Cell Mimetics: Attempt to recreate the structure and function of RBCs by encapsulating hemoglobin and necessary enzymes within a synthetic polymer shell or nanoparticle. These systems aim to reproduce the flexible, biconcave shape of RBCs while incorporating functional components like carbonic anhydrase and antioxidant systems to mimic natural RBC behavior. Specific approaches include:
Polymeric Shells: Encapsulating hemoglobin to improve oxygen delivery while preventing free hemoglobin toxicity.
Nanoparticles: Using biocompatible polymers or liposomes to encapsulate hemoglobin and mimic RBC function, providing better oxygen transport and longer circulation times.
Advantages of cell mimetics include reduced oxidative stress and longer circulation in the bloodstream compared to free hemoglobin. However, the complexity of their design makes large-scale production, stability, and immunogenicity key hurdles. Additionally, requires achieving optimal flexibility and flow properties similar to native RBCs.
Bone marrow organoid: The skull contains a small amount of bone marrow, predominantly yellow marrow, which has a low red blood cell (RBC) production capacity. However, if this marrow could be reprogrammed with erythropoietin (EPO) and other hematopoietic growth factors to favor red blood cell lineage, it might supply enough RBCs to meet the brain's oxygen needs when connected to an ECMO (extracorporeal membrane oxygenation) system.
Gas exchange
Role: To oxygenate the blood and remove CO2, maintaining pH balance and gas homeostasis.
Natural process: Oxygen diffuses from the lung alveoli into the blood, binds to hemoglobin in red blood cells, and is transported to tissues. CO2, mostly transported as bicarbonate, is carried back to the lungs and diffuses into the alveoli to be exhaled. Both processes are driven by partial pressure gradients.
Artificial alternative:
Gas Exchange Membrane (Artificial Lung): The perfusate flows through a system of tubes with gas-permeable membranes, where oxygen diffuses in and CO2 diffuses out based on partial pressure differences, replicating the natural gas exchange process.
Chemical Absorption (CO2 Removal): CO2 is absorbed using chemical solutions like sodium hydroxide or carbonate buffers. This process removes CO2 from the perfusate but requires a separate oxygenation system.
Oxygenation via Oxygenators: Oxygenators similar to ECMO (heart-lung machine) are used to introduce oxygen directly into the perfusate.
ECCO2R (Extracorporeal CO2 Removal): Focuses on removing CO2 from the perfusate using low-flow systems, ideal for scenarios where CO2 buildup is the primary concern while maintaining stable oxygen levels.
Metabolic waste removal
Role: Efficient waste removal is critical to prevent toxic buildup and maintain brain function.
Physiological mechanism
Blood: Waste products from brain cells are carried by the blood to the kidneys and liver for filtration and detoxification.
Cerebrospinal Fluid (CSF): CSF also plays a role in removing waste products from the brain. CSF is produced in the ventricles of the brain, circulates through the brain and spinal cord, and is eventually absorbed into the bloodstream via arachnoid villi in the dural sinuses. From there, waste products are filtered out by the kidneys and liver.
Artificial alternative
Closed-Loop System: Filters blood and cerebrospinal fluid (CSF) and reinfuses essential nutrients, electrolytes, and regulatory molecules, mimicking the natural filtration functions of the kidneys and liver.
Hemodiafiltration (HDF) Systems: HDF combines hemodialysis and hemofiltration to effectively remove both small and larger waste molecules, excess ions, and toxins. Using a semi-permeable membrane, HDF provides both diffusion and convection-based clearance, ensuring comprehensive waste removal.
Advanced Filtration: Utilizes methods like nanofiltration or chemical treatments to remove micro-toxins and larger harmful substances.
Synthetic Liver Support Systems: Detoxifies blood using enzyme-based or sorbent-based technologies.
CSF Shunts: Drains excess cerebrospinal fluid into an external filtration device.
Pathogen protection
Role: The brain and head require robust protection against pathogens such as bacteria, viruses and fungi.
Circulating immune cells
Role: Defend against systemic infections and pathogens.
Natural mechanism: Generated in the bone marrow and includes various types such as lymphocytes (B cells and T cells) and neutrophils. T cells mature in the thymus.
Artificial alternative: immune cells harvested from the individual can be expanded ex vivo and periodically re-infused to provide targeted pathogen protection. The presence of hematopoietic stem cells in the skull offers some local immune cell production, but the absence of a thymus and broader bone marrow limits the ability to adapt to new pathogens. Regular monitoring and external immunotherapies or updated engineered immune cell infusions are needed to maintain effective immune defense.
Resident immune cells
Role: Maintenance of cellular debris and removing pathogens.
Natural Mechanism: Brain-resident macrophages (microglia).
Artificial Alternative: Periodically replenished or enhanced microglia.
Immunoglobulins (antibodies)
Role: Critical for immune response, neutralizing pathogens.
Natural Source: Produced by B cells in the immune system.
Artificial Alternative: Monoclonal antibodies produced using hybridoma technology or recombinant DNA technology.
Complement proteins
Role: Enhance the ability of antibodies and phagocytic cells to clear pathogens.
Natural source: Produced mainly in the liver by hepatocytes, and by macrophages.
Artificial alternative: Recombinant technology.
Sterility
Production: All components must be produced in sterile conditions.
Storage: Nutrients, fluids, and components should be stored in sterile environments.
Delivery systems: Use sterile infusion lines and equipment to prevent contamination.
Monitoring: Regularly check for contamination and maintain sterility.
Sealing: head should be encased in a transparent sealed container.
Note: is sterility is attained, immune cells are not essential.
Thermoregulation
Role: Maintaining the brain’s normothermic conditions is crucial for its proper function, as deviations can impair neurological processes.
Physiological mechanism
Thermogenesis: The body organs generate heat through metabolic processes, maintaining homeostasis via feedback mechanisms involving the hypothalamus and hormonal signals.
Implementation strategy
Retaining the head: If the head is retained, it can partially thermoregulate via intrinsic mechanisms such as blood flow regulation and metabolic activity.
Hormonal cues: May require hormonal cues for optimal thermoregulation. Key hormones involved in thermoregulation include thyroid hormones, which influence metabolic rate. Can be infused via artificial blood.
External thermoregulation: via AC system installed in the MAB.
Circulation
Role: Adequate (micro-)circulation is crucial for delivering nutrients and oxygen to the brain and removing metabolic waste products, ensuring optimal brain function.
Physiological Mechanism
Heart: The heart pumps blood through the circulatory system, delivering oxygen, nutrients and other factors to tissues and organs, including the brain, and removing waste products.
Arteries: These vessels carry oxygen-rich blood away from the heart to the body’s tissues. They branch into smaller arterioles and eventually into capillaries, where the exchange of oxygen, nutrients, and waste products occurs at the cellular level.
Veins: Veins return oxygen-depleted blood and waste products from the capillaries back to the heart for reoxygenation and removal of waste via the lungs and kidneys.
Artificial Alternative
Total Artificial Heart (TAH): A mechanical device, already in use today, designed to replicate the function of the natural heart, ensuring continuous blood flow and pulsatility (although currently ther is no consensus on whether continuous or pulsatile flow is preferable for organ perfusion).
Components
Pumping mechanism: Mimics the heart's ability to generate pressure and move blood through the circulatory system. It typically includes:
Ventricular chambers: Artificial chambers that receive and eject blood.
Valves: One-way valves to ensure unidirectional blood flow.
Diaphragms or pistons: Mechanisms that create the pumping action.
Control systems: Advanced electronics that regulate the pump’s speed and output to match the head’s needs. This means maintaining sufficient flow rates to achieve adequate and homogeneous perfusion, and maintaining laminar (non-turbulent) flow, while avoiding unnecessary shear stress. This requires:
Sensors: Monitor real-time blood pressure, flow rate, and oxygen levels.
Microprocessors: Process sensor data to adjust the pump dynamically.
Battery and power supply: Ensures the TAH operates continuously, with options for external power and rechargeable batteries.
Communication interface: Allows for remote monitoring.
Fluidic System: A biocompatible network of pipes cannulated to the head’s and brain’s major blood vessels, designed to carry synthetic blood in and out, effectively replicating the natural circulatory process.
Mechanical support
Role: The brain requires structural support and protection to ensure its functionality and prevent injury.
Physiological mechanism
Skull: Provides a hard, protective casing that shields the brain from external impacts.
Cerebrospinal fluid (CSF): Cushions the brain, maintaining pressure and providing a buffer against mechanical shocks.
Implementation Strategy
Retain the entire head: including the skull and facial structures, to provide natural protection and support.
Transparent shield: Add an additional layer of protection by installing a tough, transparent shield over the head.
Dynamic homeostasis management
Release of materials: Materials can be stored within specialized compartments controlled by a computer that will manage their precise release at the correct doses and timing.
Continuous monitoring: Continuously track not only nutrient levels but also other critical factors like temperature, pH, hormone levels, and oxygen saturation in the artificial bloodstream.
Adaptive regulation: Implement advanced feedback systems that automatically adjust the delivery of nutrients, hormones, and other essential components based on real-time sensor data.
Comprehensive data integration: Use machine learning models to anticipate the brain's needs based on historical and real-time data, adjusting the artificial environment proactively.
User feedback: Incorporate subjective feedback from the individual, such as stress levels, sleep quality, and mood.
Hormones example
Hormone Levels: Use biosensors to continuously measure levels of signaling molecules like insulin, thyroid hormones, cortisol, and melatonin in the synthetic blood.
Secondary hormones: Monitor levels of other hormones that respond to these signaling molecules for a comprehensive feedback loop (e.g., ACTH for cortisol regulation).
Examples:
Insulin: Continuous glucose monitoring (CGM) sensors in synthetic blood.
Thyroid Hormones (T3 and T4): Sensors measuring metabolic rate and oxygen consumption.
Cortisol: Sensors detecting cortisol levels and secondary markers (e.g., ACTH).
Melatonin: Light sensors simulating natural light-dark cycles and melatonin levels.
Closed-loop system
Blood recycling: Approximately 1K liters of blood circulate through the brain each day. Practically, recycling a few liters of blood via filtration and replenishing systems, similar to natural body processes, is essential.
Filtration and replenishment: Implement advanced filtration systems to remove waste and toxins, while replenishing essential nutrients and electrolytes to maintain blood quality.
Input materials
Manufacturing
Bioproduction: Utilize large-scale bioreactors for the synthesis or extraction of essential molecules, including proteins, amino acids, fatty acids, vitamins, and metabolites. This method ensures high-purity production on an industrial scale.
Formulations: Develop ready-made formulations that combine essential proteins and nutrients in precise ratios, tailored to specific physiological needs (e.g., high-energy demands, maintenance).
Storage
Stability: Manage the limited shelf-life of substances by employing techniques like lyophilization to preserve them in a stable powder form for long-term storage.
Freeze-drying: Use freeze-drying to create stable, reconstitutable powders from sensitive materials, ensuring long-term viability.
Cooling: Incorporate cooling systems to extend the shelf life of perishable materials.
Mobility
Portable supply unit: Design a compact, mobile storage unit with integrated freeze-dried formulations, cooling mechanisms, and reconstitution systems to sustain brain function during movement or disconnection for several days.
Power supply
Power source: Filtration systems, pumps, and other critical components will require a reliable electrical energy supply.
Batteries: High-capacity, rechargeable batteries should be used to ensure continuous operation, even during mobility or temporary disconnection from external power.
Renewable energy: Incorporate solar panels as a supplementary energy source to enhance system reliability and reduce dependency on conventional power sources.
Approximation of energy Demands for a MAB
Filtration systems: Typically, dialysis machines require about 1–2 kWh per treatment, which could be a rough baseline.
Pumps: Heart pumps (like those in artificial hearts) generally consume about 5–15 watts continuously.
Cooling systems: Depending on the design, could add another 50–200 watts.
Monitoring and control systems: Could require an additional 10–50 watts.
Daily energy consumption: Approximately 2-8 kWh per day, depending on the exact configuration and usage.
Sensory input
Role: While not strictly necessary for survival, sensory input is crucial for experiencing the external environment, which is essential for maintaining long-term brain function and overall well being.
Physiological Components
Cranial Nerves: There are 12 pairs of cranial nerves, each with specific functions:
Olfactory nerve (I): Sense of smell.
Optic nerve (II): Vision.
Oculomotor nerve (III): Eye movement and pupil dilation.
Trochlear nerve (IV): Eye movement.
Trigeminal nerve (V): Facial sensation and chewing.
Abducens nerve (VI): Eye movement.
Facial nerve (VII): Facial expressions, taste, and salivary glands.
Vestibulocochlear nerve (VIII): Hearing and balance.
Glossopharyngeal nerve (IX): Taste and swallowing.
Vagus nerve (X): Autonomic functions, mainly gut regulation (not needed in an artificial setup).
Accessory nerve (XI): Shoulder and neck muscle movement.
Hypoglossal nerve (XII): Tongue movement.
Spinal cord: Transmits sensory and motor signals between the brain and the rest of the body.
Sensory organs
Eyes: Vision.
Ears: Hearing and balance.
Nose: Smell.
Tongue: Taste.
Skin: Touch, pressure, temperature, and pain.
Implementation strategies
Retention of cranial nerves: By retaining the entire head, most cranial nerves are preserved, maintaining the functionality of sensory organs.
Exceptions: The vagus nerve can be excluded since it is primarily involved in gut regulation, which is not necessary in an artificial setup. The spinal cord is also not essential as there is no body to transmit signals to.
Output
Role: Communicating thoughts to other individuals.
Physiological components
Mouth and vocal cords: Enable speech production and verbal communication.
Facial expressions: Convey emotions and non-verbal communication.
Implementation strategy
Retaining the head: Muscles should still function, allowing for non-verbal communication through expressions. While retaining the head preserves the mouth, without the lungs and throat, vocal sounds cannot be generated naturally.
Artificial alternative
Eye-tracking communication systems: A computer system that tracks eye movements to generate audio, similar to the technology used by Stephen Hawking. This system converts gaze patterns into speech or text, providing a means of communication.
Brain Machine Interface (BMI): Direct neural control of speech synthesis systems, enabling more fluid and natural communication.
Mobility
Transportability: The MAB should be designed to be relatively easy to transport in case of emergencies.
Autonomous motion: wheels can be installed to allow autonomous movement, controlled by the user’s eye movements for added flexibility and mobility.
Head movement: Head can be installed on an arm that can rotate in all directions.
Surgical procedure
Arteries fusion
Objective: Ensure continuous and stable blood flow to the brain.
Procedure
Fuse the four major cranial arteries: two internal carotid arteries and two vertebral arteries, as well as the two facial arteries, with the MAB system.
Use vascular anastomosis techniques to connect these arteries securely to the MAB system, ensuring a seamless connection that maintains proper arterial blood flow.
Continuously monitor arterial pressure and flow rates to ensure that the perfusion is adequate and stable.
Venous drainage management
Objective: Ensure efficient removal of deoxygenated blood and prevent intracranial pressure buildup.
Procedure
Cannulate the internal jugular veins and any other major venous pathways to facilitate venous outflow.
Connect these veins to the MAB system to maintain a closed-loop circulation, allowing for the continuous removal of deoxygenated blood.
Regularly monitor venous pressure and flow to ensure that the system is functioning correctly and preventing venous congestion.
Body removal
Objective: Isolate the head while maintaining the integrity of the vascular connections.
Procedure
After confirming stable blood flow through the MAB system and proper venous drainage, carefully sever the connections between the head and the rest of the body.
Use surgical precision to avoid damaging the remaining vascular structures.
Immediately apply hemostatic agents to control any bleeding from the severed vessels, ensuring minimal blood loss.
Capillary management
Objective: Prevent blood loss from smaller vessels in the neck region.
Procedure: Apply hemostatic agents or cauterization techniques to seal any exposed capillaries or small vessels in the neck.
Sealing the neck
Objective: Create a secure closure at the base of the head to prevent any exposure or leakage.
Procedure
Use the remaining skin and tissue from the neck to fashion a sealed closure around the base of the head.
Reinforce the closure with medical-grade adhesives, sutures, or synthetic barriers to ensure a strong and durable seal.
Complexity
One of the major challanges is developing synthetic red blood cells, especially when considering the need for large-scale production. Although advancements are being made, the technology is still in its early stages. Synthesizing blood plasma is as complex. While some components, like nutrients, can be extracted from organic compounds, replicating the full spectrum of human plasma proteins will require synthesis. Creating universal recombinant plasma with all the necessary proteins is a daunting task, because different proteins often requires specific processing and conditions. Moreover, while blood donations involve allogeneic blood transfer, it remains unclear how the residual endogenous immune system might respond to this exogenous plasma over the long term. Of course, tailoring the proteins to each person’s DNA adds yet more complexity.
The challanges in making brain perfusate are somewhat analogous to the challenges faced in developing media for cultivated meat, growing organoids, or supporting artificial wombs. However, my instinct is that maintaining homeostasis in an already developed and vascularized organ is generally less complex than facilitating embryonic development or unphysiological in vitro organ development.
Although the develpment of an MAB entails considerable R&D, I believe they are all tractable within a reasonable timeframe (two decades if taken seriously like the manhattan project). None of the proposed artificial alternatives require a scientific breakthrough to be realized. The project primarily demands engineering expertise to integrate existing technologies effectively. Success will depend much on how fine-tuned the plasma composition has to be for the brain to remain viable. In comparison, age-reversal technologies face numerous unresolved questions and potentially hard limitations, such as damage types with no endogenous repair, making it, in my opinion, a more uncertain endeavor.
The regulatory path for an MAB is likely shorter and more straightforward. Unlike age-reversal treatments, which would require extensive clinical trials involving thousands of participants iteratively over many years, the MAB could progress through a more focused and accelerated testing process. Initial trials could be conducted on pigs (mice and rats are too small), progress to non-human primates, and eventually on to comassionate use for terminally ill humans patients. Even a single human case study could provide invaluable insights to enable fine-tuning the MAB.
A more direct alternative to rejuvenation is cloning. If a biological clone could be generated and grown in a lab setting, it would primarily require advancements in surgical techniques to attach a living head/brain. A universal clone might be developed with an immune system tailored to each patient, improving scalability. However, it is unclear if this approach would be faster. On the one hand, it utilizes natural developmental processes. On the other hand, it is a slow process. Moreover, ethical concerns would necessitate suppressing parts of the clone's brain, which poses a significant complication, because it might affect development. Even with this modification, cloning is likely to remain highly controversial. In contrast, an android body offers the advantages of being inherently scalable, independent of biological time constants, and more amenable to future augmentation. Ultimately, the transition to android bodies seems unavoidable in the long term.
State of the art
Some progress and POC has already been made in developing brain perfusion devices. In 2019, Yale researchers made significant progress in this area by creating a specialized perfusion system designed to support pig brain homeostasis outside the body. This device, known as the BrainEx system, used a custom perfusate, delivering oxygen and nutrients while removing waste products. The system maintained circulation and metabolic activity within the brain, preserving the structural integrity of brain cells and reducing cell death.
Building on this progress, another study explored the maintenance of pig brain function under extracorporeal pulsatile circulatory control (EPCC). EPCC systems use pulsatile flow patterns to better mimic natural circulation, providing a rhythmical supply of oxygen and nutrients to brain tissue. This method aims to replicate the physiological conditions of a living organism more accurately than traditional steady-flow perfusion. The pulsatile nature of EPCC can improve microcirculation within brain capillaries, enhancing the delivery of oxygen and nutrients while aiding in the removal of metabolic waste. This study indicate that with carefully controlled perfusion systems, it is possible to maintain not only the viability but also the functional activity of complex brain tissues ex vivo.
These perfusion experiments and others rely on physiological blood or simple perfusates, which is not a scalable approach. However, several companies are advancing synthetic RBCs and hemoglobin-based replacements. While no company is currently focusing solely on synthetic plasma, significant work is being done on comprehensive blood substitutes. For example, DARPA has invested $46 million into the University of Maryland School of Medicine to develop a whole blood product that can be stored at room temperature, with the goal of transfusing wounded soldiers within 30 minutes of injury. This project aims to combine synthetic RBCs from KaloCyte, synthetic platelets from Haima Therapeutics, and a freeze-dried plasma product from Teleflex, creating a fully functional blood substitute for use in field settings.
Several key players are pushing the frontiers in synthetic RBCs and hemoglobin-based therapies:
HbO2 Therapeutics: Developing Hemopure (HBOC-201), a hemoglobin-based oxygen carrier derived from bovine hemoglobin. Approved in South Africa and Russia and used under compassionate use in over 60 countries, Hemopure boasts longer shelf life and universal compatibility. However, it faces challenges such as short half-life, risk of vasoconstriction, and potential oxidative stress.
Prolong Pharmaceuticals: Developing Sanguinate, a pegylated bovine hemoglobin with a carbon monoxide-releasing molecule. It is in Phase 2 trials for sickle cell disease and other indications. While pegylation may reduce toxicity and CO release provides anti-inflammatory benefits, long-term safety and efficacy remain to be proven.
HEMARINA: Exploring natural extracellular hemoglobin from the marine lugworm Arenicola marina in their product M101. This product, in preclinical and early clinical stages, has shown promise in organ preservation due to its high oxygen affinity and ability to function over a broad temperature range. However, scalability and immunogenicity remain challenges.
RedC Biotech: Developing biomimetic RBCs, with polymeric shells filled with hemoglobin and key RBC enzymes to mimic natural RBC function. Still in preclinical stages, this approach has potential for longer circulation and the inclusion of antioxidant enzymes to reduce oxidative stress. However, the manufacturing complexity and potential immunogenicity pose significant hurdles.
KaloCyte: Developing ErythroMer, a nanoparticle-based synthetic RBC encapsulating hemoglobin and other vital components. This product is designed to mimic multiple RBC functions, including oxygen delivery and carbonic anhydrase activity. It is in the preclinical stage, with research funded by the U.S. Department of Defense. Challenges include scaling up production and optimizing circulation time.
Inherent limitations
Brain aging
I aknowledged upfront that as long as intrinsic brain aging is not address, open-ended longevity cannot be attained. True, there is a “parabiosis effect” where young circulating factors slow and counter brain aging. Potentially, optimizing the MAB can buy us some time, but probably not beyond the current maximum human lifespan. To acheive open-ended longevity, the MAB must be complemented by either a brain rejuvenation therapy (which may defeat the purpose, because it could be broadly applied to the entire body), or progressive brain replacement as proposed in the previous post.
Experience
Having a physical body is a crucial aspect of the human experience. If feasible, rejuvenating the natural body is vastly superior to relying on an MAB, which represents a significant reduction in quality of life. Though advancements in robotics and neural interfaces may eventually restore mobility, sensation, and other functions—or even surpass physiological functions—the MAB is currently justifiable only in extreme circumstances. These include cases involving severely injured, ill, or extremely aged individuals whose bodies are afflicted by chronic pain and fatigue. In these cases too, the MAB should be viewed as a temporary measure and a stepping stone toward becoming an android in the more distant future when augmentation becomes available.
Dependence on supplies
Unlike natural human bodies that can sustain themselves with food, water, and air—all readily available in the environment—an MAB creates a dependency on specific, artificial supplies. Mobility may be limited, and a person using an MAB would require access to artificial blood products. In the event that these supplies run out, there are few viable alternatives, with perhaps plasma donations offering only short-term survival. This can theoretically be resolved if a bioreactor that intakes simple nutrients is installed in the MAB, but this constitutes a considerable complication.
Market strategy
The various components of the Mind-Associated Body (MAB) each offer independent benefits and can be developed concurrently, creating multiple market opportunities. Some key applications include:
Organ preservation: Developing techniques to keep the brain or head alive will likely progress through applications in other organs first. Enhancing organ perfusion and preservation techniques is valuable, as extending organ shelf life is a major challenge in transplantation. Improved perfusion methods could reduce organ rejection rates and increase the availability of viable organs for transplant, addressing a critical need in medical practice.
Blood transfusion: Blood transfusions for traumatic injuries currently rely on donated blood, which can be limited and costly. Developing an affordable artificial blood substitute would meet a significant demand in healthcare, not only for emergency trauma care but also for surgeries, chronic anemia management, and other medical conditions requiring regular transfusions. This market is vast, and an effective synthetic alternative could provide a reliable and consistent supply.
Immune cell grafts: Engineering immune cells derived ex vivo from a patient's bone marrow or circulating immune stem cells presents a valuable opportunity. Individuals could bank a small sample of their bone marrow, which could later be used to create personalized immune cell therapies. These engineered immune cells could be re-infused in old age to boost the immune system, potentially combating age-related immune decline and providing a tailored approach to immune health.
Beyond the MAB
Brain-Machine Interface (BMI)
BMI technologies are advancing to make artificial bodies more immersive. Sensory input enhancements involve using robotic systems with sensors that detect touch, pressure, temperature, and pain, converting these stimuli into electrical signals that the brain can understand. Direct stimulation using microelectrodes on the sensory cortex is another approach, aiming to provide a more realistic and precise sensory experience. For output, BMIs can decode brain signals related to speech, translating them into synthesized voice outputs. These systems can adapt to the user’s unique speech patterns, creating more natural communication. Robotic faces and digital avatars can be used to replicate human expressions, enabling realistic non-verbal communication and interaction. As the technology evolves, it could also enable broader applications, such as enhanced cognitive functions and direct interfacing with remote digital systems.
Robotics
Robotics integrated with BMI can significantly enhance mobility and functionality. Advanced prosthetics and exoskeletons controlled by BMI allow users to perform precise movements, closely mimicking natural motor functions. Machine learning algorithms can improve these systems by learning from user interactions, making control more intuitive and responsive over time. These improvements aim to provide seamless integration between the brain and robotic components, allowing users to navigate and interact with their environment effectively. The goal is to make life with an artificial body as fulfilling and natural as possible by closely replicating human physical and sensory capabilities. These augmentation technologies will probably develope in tandem with MAB and irrespective of the MAB mission.
Virtual reality
An alternative to MAB physical augmentation is fully committing to virtual reality. Since our experiences are ultimately processed in the brain, a highly immersive virtual reality that stimulates the senses could potentially offer a preferable existence, free from the physical limitations and suffering of the real world. In such a scenario, individuals connected to MABs could form communities, creating a shared virtual environment similar to "The Matrix," but with the awareness of being in a virtual setting.
This concept may seem dystopian to some, influenced by Hollywood’s portrayal of virtual reality as inherently negative. Personally, I don’t see the inherent wrong in choosing to live in a carefully crafted virtual world, as long as it is sustainable. The individuals will be fully aware of the context, so it’s not like “taking the blue pill”, i.e. subscribing to a delusion. It’s about choosing a reality that maximizes well-being and quality of life within the confines of technological possibilities.
Expert input needed
While the MAB concept may sound highly speculative, potential implementation is under consideration. If you have expertise in any of the relevant domains contributing to this technology, I would be interested in having a conversation.