Present-day blood glucose monitoring test kits are antiquated, requiring a finger prick to draw blood. This study’s purpose was to develop a paper-based microbial fuel cell (pMFC) for glucose monitoring in saliva, a noninvasive indicator of systemic glucose levels (GL) compared to blood (R^2 = 0.823). pMFC performance was recorded via a customized LabVIEW interface (NI USB-6212). Each experiment was performed using 8 devices, each with glucose concentrations ranging from 0.0 mg/dL to 19.68 mg/dL using the bacterial species S. oneidensis. All experiments were performed 5x. In the first phase of this study, a 3-layer pMFC (3-pMFC) and a 2-layer pMFC (2-pMFC) were designed to determine optimal efficiency. The 3-pMFC prototype consisted of 3 distinct layers: (i) the anode, (ii) the anodic reservoir/wax membrane, and (iii) the air-cathode; the 2-pMFC consisted of 2 distinct layers: (i) the anode, and (ii) the anodic reservoir/cathode. The 3-pMFC showed 58% higher sensitivity than the 2-pMFC to distinguish between average diabetic (D) and average nondiabetic (ND) salivary GL, and was used for the remainder of this study. There was a 72% voltage difference between D and ND voltage levels after 5 minutes (p<0.0001). The 3-pMFC showed a linear range of voltage output (R^2 = 0.93) and distinguished GL ±0.2 mg/dL (p<0.005). The 3-pMFC’s current increased linearly during a 16-day longevity test, signifying that bacteria proliferated for 16 days post-inoculation. This study fabricated an accurate pMFC to detect and monitor salivary GL. Future studies will investigate the use of wastewater as the device’s reducing agent.
Air Force Research Laboratory on behalf of the United States Air Force: First Award of $750 in each Intel ISEF Category
Intel ISEF Best of Category Award of $5,000