Development of a Self-Powered Microneedle Based Wearable Electrochemical Sensor for Glucose Monitoring

Abstract

Diabetes is increasingly being recognized as a worldwide public health concern owing to the affected rate of the patients in the past years. One of the major barriers to the disease control is the lack of sensitive and reliable point-of-care device that can provide quantitative diagnosis and monitoring. The wearable sensing technology has the potential of revolutionizing the precision medicine and personalized healthcare system. Within the emerging class of wearables, the microneedle-based sensors play a key role in combining the advantages of monitoring the analytes in interstitial fluid (ISF) and minimally invasive skin pricking. However, such devices require appropriate power sources to realize their full capacity, and the increasing power costs, global warming, and environmental pollution are certain aspects that needs to be pondered upon. Researches are dedicated on power generators with focus on wearable energy harvesters to address the issue of power supply. Thermoelectric generators (TEGs) have the ability to generate power by transforming thermal energy to electrical power output. Herein, we have developed a microneedle based enzymatic, electrochemical glucose sensing system powered by TEG utilizing the body heat. 1 mm stainless steel microneedles were sputtered with gold and platinum, and further coated with graphene paste, glucose oxidase, poly-hydroxyethyl methacrylate, and nafion. The fabricated device exhibited a good sensitivity, and a wide linear range. According to the World Health Organization (WHO), the normal glucose level in human body are between 4.0 mM to 5.6 mM, and our device has shown a concentration dependent output current signal from 4.0 mM to 24.0 mM. The device has also exhibited excellent detection results in real-sample (artificial ISF) in vitro study as well as in vivo analysis performed in 12 – 15 weeks SD rats. The device is completely self-powered where the TEG derives power from the temperature gradient between the body heat and the exposed environment. The novelty of this work lies in integrating the microneedle-based sensing device with the TEG as the power source. The results indicate a promising self-powered sensor with the renewable and sustainable source of power ensuring continuous operation.