Growing The Earplugs

The research for our Tinnitus-preventing mushroom friends began with understanding what Mycelium can actually provide for us as a material. Mycelium (the branching root-like network of fungi) is cultivatable on both agricultural and plant-based byproducts, allowing the waste materials to become the foundation of a new bio-based composite (Sydor et al. 2022). Once the mycelium is grown, it can be dried and heat-treated to prevent further fungal growth (Don't worry. You won't actually have mushrooms growing in your ears!), creating a lightweight product with the potential to be engineered into a variety of shapes and sizes. Research has also shown very promising acoustic properties in mycelium composites, particularly due to their porous internal structure. (Boisvert et al. 2023).
 

Designing for the Human Ear

The biggest challenge for us is effectively translating the properties of these materials into something small and precise enough that you can fit it in your ears. So we explored how mycelium could potentially be formed or combined with other eco-friendly materials to provide a perfect balance of structure, flexibility and comfort. Polylactic acid (PLA) and Polyhydroxyalkanoates (PHA) were heavily considered as potential materials for future developments where extra rigidity may be required, for example. However, at this stage, these are for future investigation and research rather than established solutions.

Fun Fact: Our prototype for our earplugs was actually 3D printed entirely out of PHA, keeping with the bio-friendly mantra throughout our design process! You can see more photos of the finished prototype along with the sketches/designs on our development page!
 

Music to Your Ears

Our last and ongoing area of research is the acoustic performance of the earplugs. Whilst traditional foam earplugs do provide "substantial" protection, their attenuation can often be uneven across frequencies, making music and external sound appear "muffled". This is addressed in high-fidelity earplugs through meticulously designed geometries and acoustic filters, rather than strictly relying on materials themselves to do all of the heavy lifting. 

Our task, therefore, asks the question of whether the porous structure and geometry of mycelium could be utilised for similar purposes and, as a result, reduce harmful sound levels whilst still preserving as much character and clarity in the sound as physically possible.