Project 02
KombuGas Glucose Monitor
Blood glucose regulation via the glycolysis cycle in kombucha microbial systems
My work explores the intersection of living materials, human-centred health management and interaction design. Using bacterial cellulose cultivated from kombucha, I investigate material behaviours — such as the glycolytic cycle — as a basis for more independent self-management for people with type 1 diabetes through wearable systems. The projects range from closed-loop glucose management devices to non-invasive, antimicrobial CGM gloves, where microbial responses enable the bio-visualisation of long-term glucose levels and drug delivery.
Living with type 1 diabetes
Type 1 diabetes is an autoimmune disease that destroys pancreatic beta cells, requiring lifelong dependence on insulin from the moment of diagnosis. Management relies on finger-stick glucose tests or continuous glucose monitors, insulin pens, and an HbA1c test at the hospital every two to three months — a measure of average blood glucose over that period.
Continuous glucose monitors are invasive, inserted under the skin. Non-invasive alternatives — microneedle electrodes, electrochemical sweat sensors, transdermal laser micropores — point toward another path. Patient empowerment means more power in decision-making in everyday life: how might people with type 1 diabetes become more decisive about their own HbA1c?
Glucose in, gas out
Kombucha is fermented by a SCOBY — a bacterial cellulose mesh made by acetic acid bacteria and yeast. The yeast ferments sugar into alcohol and carbon dioxide; the bacteria oxidise the alcohol into acids and form more cellulose. The cellulose itself is mildly antibiotic, non-allergenic to skin and absorbs sweat.
The glucose accumulated in kombucha is converted into ethanol and carbon dioxide. Over eleven days of observation the SCOBY thickened and bubbles became more prominent, and the gas was confirmed as carbon dioxide with a limewater test.
A sustainable home system
The core concept is a sustainable home system that supplements HbA1c monitoring, empowers patients with type 1 diabetes, and uses gas generated from long-term kombucha fermentation to power a home-based insulin microneedle injection system.
- Sensor wearPatients wear a bacterial-cellulose sensor that collects sweat glucose.
- Sensor replacementThe bacterial cellulose is replaced every 3–4 days.
- Home fermentationThe used cellulose joins a home kombucha culture to continue fermenting.
- Gas & feedbackFermentation produces gas in proportion to long-term blood glucose levels.
- Microneedle injectionThe gas drives insulin microneedles for demand-based dosing.
Measuring the gas
Early attempts used syringes to capture gas from fermentation bottles, but the large bottles left too much space and pressure was insufficient. A second round tested “boosters” — eggshell, ginger, lemongrass and lime — to see which produced the most gas; a third round switched to balloons as a more intuitive comparison and added pine needles as a new booster.
Building on these results, I estimated gas production at roughly 6.68 mL per gram of glucose, and about 1.6 mL of gas over three months when blood glucose remains elevated.
A self-powered dose
Applying a spring-driven pump to a fermentation system introduced too many variables, so I replaced the spring with a balloon actuated directly by the gas. Microneedles — which penetrate only the superficial dermis without touching nerve endings — became the final delivery point. The airbag pump undergoes gentle pulsations driven by CO₂ from kombucha fermentation, propelling medicine from the microneedle chamber into the skin at a controlled rate: a self-powered, metered-release delivery system requiring no external power source.
Home-use kombucha injection recorder
The recorder holds kombucha cultured with ginger at its centre, a container where uniformly distributed pores let collected sweat mix thoroughly with the culture, a coin battery powering a flexible heating plate, an insulin microneedle patch and medical adhesive gel. A slightly enlarged, ergonomically curved form prevents accidental needle misfire. The prototype is 3D printed in transparent material so users can watch the CO₂ bubbles accumulate over time.
Reusable kombucha-based sweat GMC
I cultivated multiple batches of kombucha biofilm, washed and dried them into stable materials for wearable structures. The glove follows a palm-print pattern for comfort; movement tests showed where the material wrinkled, so I added folds and removed the palm section. Its replaceable SCOBY collects sweat and is swapped every three days, while a reassembled glucose-sensing component sits on a flat area of the hand.
Two devices, one cycle
The recorder and the glove work in coordination through a sweat-collecting kombucha patch: glucose accumulated in the patch is metabolised, generating gas that inflates the air pump.
- Remove the sensor glove after three days of wear.
- Peel off the SCOBY that has accumulated sweat and replace it with a new one.
- Insert the used SCOBY into the recorder every three days for three months.
- Over the three months the kombucha ferments, producing gas you can watch.
- At the three-month mark, press the heating switch.
- Align the navel with the device’s concave curve; expanding gas pushes the microneedles into a safe range for injection.
Living materials can be active participants in design — capable of sensing, computing and responding to minute changes in both the environment and the human body, shifting the relationship from monitoring to interaction, and from protection to collaboration.