Exploring Artificial RBCs
- One could imagine artificial red blood cells as devices capable of O2/CO2 uptake and release. Ones a little bit simpler than full on respirocytes
How RBCs are made
- Primer on how RBCs are made naturally
- Summary:
- Stem cell ā ejects nucleus & organelles ā intakes hemoglobin ā Finished RBC
- How hemoglobin is made: iron, B12, B9, globin chains
- body makes makes 2 million RBCs a second
- They live for ~100 days
Their structure
- Bi concave shape
- flexible membrane
- 1 RBC is filled with ~280 million Hemoglobin molecules (1 Hemoglobin carries 4 O2 molecules so one RBC carries ~1.2 billion O2 molecules)
Materials
- flexible structural proteins e.g. actin & spectrin
- Hemoglobin
Gas exchange function
- Primer on gas exchange in RBCs
- Key principle= Pressure parity allowing gases to passively diffuse. i.e. When in air sacs, because of pressure parity, oxygen is more favoured to bind to Hemoglobin. And when in tissues, because of pressure parity, Carbon Dioxide is more favoured to bind to Hemoglobin.
- O2 uptake in lungs and release in tissues:
- In lungs, where air sacs have higher O2 pressure than in blood vessels, O2 therefore diffuses into blood vessels and meets Hemoglobin which is selective to latch on to O2ā¦.. Hemoglobin + oxygen ā Oxyhemoglobin
- Red blood cells are small and flexible, and therefore can fit through many tiny capillaries.
- When at tissue sites, Oxygen is passively released, turning oxyhemoglobin back to regular hemoglobin.
- When depleted goes back to lungs to be reoxygenated.
- CO2 uptake in tissues and release in lungs
- After O2 is released, because of pressure parity, Carbon Dioxide is more favored to bind to Hemoglobin.
- Post binding, they leave and head to the lungs where CO2 is released and Oxygen in suptaken.
- Some more on the chemistry of the CO2 uptake https://youtu.be/HoaHtxgZrJ0?si=1d3ATVEJcda349bN
Synthetic ones would:
- be biconcave discs(or other suitable geometry) with diameters
- Thin membranes made of flexible gas-soluble materials
- Filled O2-CO2 selective molecules (could be hemeoglobin or alternative)
- Potentially have utility modifications e.g. higher oxygen-CO2 affinity molecules than hemoglobin, chemosensitive molecules to aid in active gas exchange, etc.