Amphibio is a conceptual design project by designer Jun Kamei proposing a wearable device that allows humans to breathe underwater by mimicking the biological function of an insect gill. This 3D-printed accessory consists of a gill-like structure and a respiratory mask designed to extract dissolved oxygen directly from the surrounding water. Amphibio is envisioned as a lightweight alternative to complex scuba gear, bridging the gap with simple free-diving. It is intended as a tool for short-term underwater exploration, enabling a user to stay submerged for longer periods.
The Science Behind Water-Air Separation
The core scientific principle behind Amphibio is biomimicry, drawing inspiration from aquatic insects like the diving beetle. These organisms survive by trapping a thin layer of air against their superhydrophobic skin, creating a physical gill known as a plastron. This air pocket functions as a gas-exchange membrane, allowing the insect to continuously replenish its oxygen supply from the water.
The mechanism relies on the physics of gas diffusion, driven by differences in partial pressure. When a user exhales, the oxygen concentration inside the air pocket drops compared to the dissolved oxygen in the surrounding water. This low partial pressure causes oxygen molecules to diffuse from the water across the membrane and into the air pocket.
Simultaneously, the exhaled breath increases the partial pressure of carbon dioxide (CO2) inside the gill. This concentration gradient forces the CO2 molecules to diffuse out of the air pocket and dissolve into the water. The air pocket acts as a stable boundary layer, facilitating the continuous, passive exchange of gases needed for respiration.
3D Printing and Material Engineering
The complex structure of the Amphibio gill is only possible through additive manufacturing, or 3D printing. Traditional methods cannot produce the intricate, microscopic network of channels and pores required for the gill’s function. This technology allows for the creation of precise, highly detailed branching structures necessary to maximize the surface area available for gas exchange.
The garment requires a specialized material that is both flexible and extremely water-repellent to create the stable air pocket. This is achieved using a custom 3D-printing filament based on elastomeric polymers, such as Thermoplastic Elastomers (TPE). These materials are chosen for their rubber-like flexibility and hydrophobic nature, which prevents water from penetrating the porous membrane while still allowing gases to pass through.
The material must be microporous, containing pores small enough to trap air and repel water, yet large enough to permit the diffusion of oxygen and carbon dioxide molecules. This specific engineering is fundamental to establishing and maintaining the plastron effect underwater. 3D printing allows the designer to tailor the garment’s form to maximize this functional surface area, often taking cues from highly folded structures found in nature.
Real-World Viability and Device Status
Amphibio remains a proof-of-concept prototype and is not a fully functioning life-support system capable of sustaining human breathing. The primary scientific challenge is the vast difference between the concentration of oxygen in air (approximately 21% by volume) and the concentration of oxygen dissolved in water (less than 1%). Extracting sufficient oxygen from this low-density source demands an enormous surface area.
Estimates suggest that a gill surface area of at least 32 square meters, and perhaps up to 80 square meters, would be required to meet the basal metabolic rate of a resting human. The current prototype is significantly smaller than this requirement, meaning it cannot provide enough oxygen for sustained survival. The practical challenge is compounded by the need to constantly move water across the large surface area to prevent the immediate depletion of dissolved oxygen directly next to the membrane.
While the device successfully demonstrates the principle of gas exchange—extracting oxygen and expelling carbon dioxide in laboratory tests—it is currently only viable as an aid to extend the time spent underwater. It is not a replacement for traditional breathing apparatus. Deep-sea diving, which requires a much higher oxygen intake and greater pressure resistance, remains impossible with the current technology.