The Lichen Limb

Julian Kennedy and Aviv Hirsch
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Brief - Julian Kennedy

 Poor air quality is a significant global health issue that is not going away. Well over 4 million deaths a year are attributed to outdoor air pollution. The "Lichen Limb" is an air-purifying arm prosthetic that uses lichen to help humans now, and to prepare them to adapt to and mitigate air pollution issues projected for the future. Like all plants, lichen naturally scrubs excess co2 from the air, but unlike most plants, it does not need dirt to survive. This makes it the perfect natural, mobile, co2 scrubber. 

Many similar natural air-purifiers use algae and an air pump to scrub co2. The "Lichen Limb" instead uses lichen because it is lighter, easier to maintain, and does not require electricity to operate. The device is designed with internal air tunnels lined with lichen that scrub away excess co2 as air passes through. The lichen tunnels spiral around a 3D-printed cone-shaped base. The tunnels are spiraled in order to maximize surface area, and two hinged pieces of clear acrylic fit around the base in order to air seal the tunnels. These features improve the efficiency of the co2 scrubbing. The "Lichen Limb" was designed as a prosthetic for practicality and social impact. The device is rather bulky and would be very difficult to attach to someone is fully limbed. Designing it as a prosthetic for below the elbow amputees allows for the necessary size of the device. Along with the goal of air purification, the "Lichen Limb" hopes to empower different limbed peoples and destigmatize disability.

Brief - Hagar Hirsch

The Lichen Limb is a prosthetic arm that hosts lichen that naturally filters toxins and provides clean air for the user. According to The United States Environmental Protection Agency’s Air Quality, living in Boston for a year one takes in a number of toxins equivalent to living with a smoker for three months. Air pollution levels in Boston, as well as worldwide, are only projected to get worse. In order to combat this lichen is the ideal choice. It acts as a natural, portable, filter as it is both very hardy and also efficient at air filtration.

The prosthesis has been modeled to fit Jul, who is a below the elbow amputee. We spoke to her about creating a comfortable prosthetic and also about what routes we could take to make the prosthetic more useful. In order to create a comfortable attachment, we are using foam padding. All mechanisms have been designed to be operated with one hand. The prosthesis contains a drill-shaped spiral to encourage air flow and to make watering the lichen easier; the outside shell contains a spring-based latch to make the device easy to open. The Lichen Limb seeks to provide a natural and streamlined solution to air pollution as well as approaching prosthesis. The Lichen Limb doesn’t replace the function of a hand. Our project sought to explore how prosthetics could be made that challenge the human form instead of replicating it.