during the current COVID-19 health pandemic, the race has been on to provide adequate numbers of personal protective equipment (PPE). designers and the general public have came out in force to offer creative solutions ranging from 3D printed shields to DIY face masks. however, as many of these designs have used plastic, elizabeth bridges and garrett benisch of sum studio have created a microbial cellulose face mask while wondering if earlier investment in sustainable bio manufacturing could have made PPE more readily available.
N95 masks are made from melt blown non-woven plastic fabric at the perfect precision in order to filter particles containing pathogens. these materials are paramount in our fight to stop the spread of COVID-19, yet essential workers are lacking supply of them. this is due to the machining and precision required to make the fabric. the machines that create melt blown fabrics are expensive, complex, and take months to build.
as bio-designers, bridges and benisch have looked to the natural world, which is full of filters, membranes, and woven barriers that are ready to be utilized or mimicked. to prove just how accessible these materials are, they decided to grow their own bacterial cellulose face mask in their home quarantine kitchen while ideating some possible ways that this prototype could be iterated to function just like the melt-blown N95 fabric that is in short supply.
bacterial cellulose is created by a common bacteria, called xylinum acetobacter, on the surface of a liquid that they inhabit. this bacteria and it’s cellulose craftwork can be grown with as little as water, tea, sugar, and a small sample to feed and let flourish. as the bacteria multiply, they knit cellulose fibers into a single membrane that can be harvested and dried as a workable material. though translucent and smooth to the human eye, microscopic images show the tight web of cellulose fibers that make up this incredible knit.
once the material is thick enough, it can be removed and hung to dry as a flat sheet. this sheet is flexible and strong, yet easily degrades into the environment. it can be waterproofed and oiled with natural ingredients to have the softness and strength of thin leather. the entire process takes around two weeks; long in its own right, but nothing compared to the geologic timescale of fossil fuels and their environmental cost. with multiple batches staggered in time, one could imagine the production of this material scaling quickly.
the prototype pictured here envisions employing the same technique to create a material with equivalent filtration to N95 masks, if not better. this material could be grown in local municipalities, in people’s homes, or even within the very hospitals that need them. as the bacteria knit to the shape of the container they are in, products can be grown in specifically shaped molds so that the sheets can be grown to standard specification.
with PPE like face masks made from cellulose, the life cycle of the product will match the user scenario. rather than petroleum plastic masks that are used once and then persist in our environment for years, these masks would compost as easily as household vegetables. with this project, bridges and benisch advocate for the use of biodesign, which could provide sustainable solutions without the damaging the environment.