Oxygen transport to tissue by persistent bubbles: Theory and simulations

Persistent gas bubbles able to traverse capillaries can be prepared from a slowly permeating gas or with a mechanical structure surrounding a gas phase. If they are permeable to gases, such bubbles will carry O₂ from the lungs to the tissues via the blood stream. Using a mathematical model based on physical laws, we present simulations of the behavior of bubbles stabilized by a slowly permeating gas (gas X). We show that the bubble persists longer if the tissue and venous blood contain N₂ to dilute gas X and slow its outward diffusion. A 6-μm-diam bubble carries 0.11 pl of O₂ during the breathing of pure O₂, so 4.6 x 10⁸ bubbles/ml in the blood will supply a normal arteriovenous difference. In conditions used for hyperbaric O₂ therapy, a bubble carries ~0.26 pl of O₂. Stabilized bubbles have the potential to transport O₂ efficiently; they release O₂ to tissue at high PO₂ and require injection of only small amounts of a foreign substance.