Theoretical model and experimental validation for underwater oxygen extraction for realizing artificial gills

Abstract

Many recent studies have employed biomimicry to develop practical systems inspired by natural mechanisms. For instance, several attempts have been made to develop an artificial gill system by mimicking plastron mechanisms, which demonstrates the potential for terrestrial animals to breathe under water by extracting dissolved oxygen and discharging carbon dioxide. In this study, we propose a theoretical model for such artificial gill system comprising essential engineering parameters such as the partial pressure of oxygen inside the system, gas permeability, surface area, and the thickness of membranes. We experimentally investigated the effect of each engineering parameter on the oxygen extraction/supply rate and then validated the theoretical model with experimental results. We also applied the same model and engineering guidelines to develop a scaled-up artificial gill system for a stag beetle. The artificial gill system extracts sufficient dissolved oxygen from water, thus demonstrating that stag beetle can survive for more than 60 h in water; however, carbon dioxide accumulates over time. We believe that the established model and supporting experimental results can further advance artificial gill technology, thereby making it possible for humans to breathe under water without using a conventional scuba gear.