Browsing by Author "Cakir, Cengiz"

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Citation Count: 0
Continuous Glycemic Monitoring Enabled by A Wi-Fi Energy-Harvesting Wearable Sweat-Sensing Patch
(Wiley, 2024) Istıf, Emın; Abbasiasl, Taher; Mirzajani, Hadi; Istif, Emin; Akhtar, Muhammad Junaid; Cakir, Cengiz; Beker, Levent
Continuous monitoring of multiple physiological parameters, such as glucose levels, temperature, and heart rate variability (HRV) is crucial for effective diabetes management and mitigating the risks associated with hypoglycemic events. These events often occur without apparent symptoms, posing a challenge for diabetic patients in managing their condition. Therefore, a non-invasive wearable device capable of continuously measuring multiple body signals to predict hypoglycemic events would be highly beneficial. In this study, a wearable patch that continuously measures glucose, temperature, and HRV is presented. The device uses a novel power harvesting system to convert radiofrequency (RF) signals with the frequency of 2.45 GHz to direct current (DC) signals to extend the battery life for further continuous monitoring. The patch is small and has a conformal structure that can easily fit onto different body parts. The screen-printed glucose sensor demonstrates a sensitivity of 10.3 nA cm-2 mu M-1, a limit of detection (LOD) of 8.9 mu M, and a limit of quantification (LOQ) of 27 mu M. The device employs a photoplethysmography (PPG) module with a peak-finding algorithm to calculate the HRV values. In vivo experiments demonstrate the validation of the device's proper operation in glucose, HRV, and temperature measurement. This study introduces a wearable patch for diabetes management, employing a unique Wi-Fi energy harvesting system for extended battery life. The device's conformal structure enables effortless placement on the body, providing continuous monitoring of glucose, HRV, and temperature. The platform presents a non-invasive physiological monitoring approach that enhances diabetes care by offering real-time data in a compact and efficient design. image
Citation Count: 12
Miniaturized wireless sensor enables real-time monitoring of food spoilage
(Nature Portfolio, 2023) Istıf, Emın; Mirzajani, Hadi; Dag, Cagdas; Mirlou, Fariborz; Ozuaciksoz, Elif Yaren; Cakir, Cengiz; Koydemir, Hatice Ceylan
Food spoilage results in food waste and food-borne diseases. Yet, standard laboratory tests to determine spoilage (mainly volatile biogenic amines) are not performed regularly by supply chain personnel or end customers. Here we developed a poly(styrene-co-maleic anhydride)-based, miniature (2 x 2 cm(2)) sensor for on-demand spoilage analysis via mobile phones. To demonstrate a real-life application, the wireless sensor was embedded into packaged chicken and beef; consecutive readings from meat samples using the sensor under various storage conditions enabled the monitoring of spoilage. While samples stored at room temperature showed an almost 700% change in sensor response on the third day, those stored in the freezer resulted in an insignificant change in sensor output. The proposed low-cost, miniature wireless sensor nodes can be integrated into packaged foods, helping consumers and suppliers detect spoilage of protein-rich foods on demand, and ultimately preventing food waste and food-borne diseases. Standard tests to determine food spoilage are costly and time consuming. A poly(styrene-co-maleic anhydride)-based sensor offers a low-cost alternative that can be linked to mobile phones for real-time spoilage analysis. The device was tested on chicken and beef samples under various storage conditions.