Among the unsolved mysteries of modern biology is the nature of a lining of blood vessels called the ‘endothelial surface layer’ or ESL. In venous micro-vessels, it is half a micron in thickness. The ESL is 10 times thicker than the endothelial glycocalyx (eGC) at its base, has been presumed to be comprised mainly of water, yet is rigid enough to exclude red blood cells. How is this possible? Developments in physical chemistry suggest that the venous ESL is actually comprised of nanobubbles of CO2, generated from tissue metabolism, in a foam nucleated in the eGC. For arteries, the ESL is dominated by nanobubbles of O2and N2from inspired air. The bubbles of the foam are separated and stabilized by thin layers of serum electrolyte and proteins, and a palisade of charged polymer strands of the eGC. The ESL seems to be a respiratory organ contiguous with the flowing blood, an extension of, and a ‘lung’ in miniature. This interpretation may have far-reaching consequences for physiology.

中文翻译：

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内皮表层的结构和功能：解开生物表面的纳米结构

现代生物学的未解之谜之一是被称为“内皮表面层”或 ESL 的血管内层的性质。在静脉微血管中，厚度为半微米。ESL 的底部比内皮糖萼 (eGC) 厚 10 倍，据推测主要由水组成，但其硬度足以排除红细胞。这怎么可能？物理化学的发展表明，静脉 ESL 实际上由 CO 的纳米气泡组成2，由组织代谢产生，在 eGC 中成核的泡沫中。对于动脉，ESL 由 O 的纳米气泡支配2和 N2来自灵感的空气。泡沫的气泡由血清电解质和蛋白质的薄层以及 eGC 的带电聚合物链栅栏分离和稳定。ESL 似乎是与流动的血液相连的呼吸器官，是“肺”的延伸和缩影。这种解释可能对生理学产生深远的影响。