Wireless Continuous Glucose Monitoring for Smart Home Diagnosis via Biodegradable Fluorescent Microneedle Sensor

According to the International Diabetes Federation, the number of patients with diabetes worldwide is 536.6 million, i.e., 10.5% of the total population. In particular, hypoglycemia is a serious condition that can cause behavioral and cognitive impairment, seizures, loss of consciousness, coma, brain damage, or death. In addition to the severity of diabetes itself, this condition can also cause serious medical complications in other organs, such as the kidneys, liver, and heart. Diabetes requires constant management to avoid unfortunate consequences, such as death. Therefore, precise monitoring of the blood-glucose level in the body, which is an important indicator for managing type 1 and type 2 diabetes, is necessary. Continuous glucose monitoring (CGM) is crucial for tracking blood-glucose levels in real-time, providing critical information to effectively prevent diabetic complications arising from hypo- or hyperglycemic episodes. While invasive lancet measurement is not compatible with CGM, commercial and research efforts have been directed toward developing biosensors for CGM. However, the current CGM sensors has discomfort from the attached transmitter on skin and require implantation and removal surgery, which increases the possibility of wounding and bacterial infection, presenting critical barriers for use. Despite the considerable progress made by commercial CGMs, there remains a pressing need to develop user-friendly, minimally invasive CGMs. Therefore, a new class of CGM biosensors is needed for monitoring skin interstitial fluid glucose, like commercial CGMs, in a user-friendly, minimally invasive way that overcomes the limitations of existing systems. Here, we introduce the CGM system consisting of biodegradable microneedle sensor array with high fluorescence sensitivity to glucose and portable smart device with image processing applications. This system produced straightforward yet robust outcomes by measuring the fluorescence intensity of microneedles, which was reversibly modulated based on glucose concentration, without the need for enzymes or reagents. Through this sophisticated integration, our system could continuously measure glucose levels without blood colleting, wound or pain over up to 3 days, clearly tracing the results of commercially available blood glucose meters like lancet diagnostic method. Users such as diabetics can easily and wirelessly check the glucose concentration with this on-demand tether free glucose monitoring system by simply taking the picture with the smartphone, thus allowing measurement at any desired time while the patient moved freely. The fluorescence intensity of the microneedle sensor, which changes according to the glucose concentration, can be successfully obtained through the mobile device equipped with software for analyzing pixel data of the fluorescence image. Compared to previous CGM studies, our system has the advantage that the sensors are ultra-thin and light, minimally invasive, very simple to use, and completely biodegraded and discharged from the body without the insertion and removal surgery. Unlike other sensors, the biodegradable microneedle eliminates the risk of the sensor broking or remaining in the body, enhancing human safety. This feature notable reduces the risk of infection and further enhances patient comfort and compliance, making our system a more prospective solution for CGM. Furthermore, the microneedle sensor-based home glucose diagnostic platform not only serves as another promising candidate for patients to help prescription and treatment, but also provides potential possibilities for improve health and quality of life. This new platform offers opportunities to autonomous and accurate CGM, a powerful and promising tool in the management of diabetes, using the glucose-responsive fluorescent microneedle sensor and user-friendly home diagnosis mobile service technology.