A self-powered glucose monitor Tanmay Kulkarni, Naomi Mburu and Gymama Slaughter Bioelectronics Laboratory, Department of Computer science and Electrical engineering, University of Maryland Baltimore County, 1000 Hilltop circle, Baltimore MD 21250, USA ABSTRACT Glucose substrates are successfully harnessed to generate electricity in a membraneless biofuel cell with a mesh network of carbon nanotubes pyroquinoline quinone glucose dehydrogenase-modified anode and a laccase-modified cathode. Using glucose as a substrate, this glucose-oxygen biofuel cell is able to produce a steady current density of 337.5 µA/cm² and an open circuit voltage of 524 mV in 360 mg/dL glucose solution. Interestingly, the fuel cell in combination with a capacitor as the transducer element can also be utilized as a glucose monitor while generating electricity simultaneously to power small electronic devices, such as light emitting diode (LED). Moreover, the self- powered glucose monitor exhibited a linear dynamic range of 9 mg/dL to 630 mg/dL glucose. These results and device demonstrations suggest that further research into self- powered glucose monitors can provide major benefit in developing a novel autonomous implantable glucose monitor platform to greatly improve the quality of life for individuals living with diabetes.. Keywords: glucose monitor, diabetes, biofuel cell, voltage boosting 1 INTRODUCTION The current epidemic of diabetes and its potential growth is a public health risk that is unsustainable and must be addressed. According to the Center for disease control (CDC) 2014 report, 29.1 million people in the U.S. suffer from the disease diabetes, which is the seventh leading cause of death. The cost incurred to keep diabetes under control was 245 billion US dollars [1]. This cost is attributed to the complications that arise due to poor maintenance of blood glucose levels. Some of the complications include retinopathy, neuropathy, gastroparesis, foot complications, ketoacidosis, kidney disease, etc [2]. Diabetes is a metabolic disorder caused by abnormal blood glucose level and is a result of either insufficient production of hormone insulin by the pancreas or the cells in the body do not respond correctly to the insulin produced. There is a significant growth in the number of people suffering from Type 2 diabetes due to the unhealthy lifestyle and stress in their daily life. Normal blood glucose levels for a healthy individual as well as an individual suffering from diabetes is provide in Table I. Table I: Normal blood sugar levels for non-diabetic as well as diabetic people. Current technology for monitoring blood glucose levels involves the use of invasive devices, such as the finger prick test using a glucometer as illustrated in Figure 1A. However, this device is bulky and at times, depending on different batches of the test strips, the meter must be recalibrated. The blood glucose reading can drift by as large as 72 mg/dL. This drift in the blood glucose level can be fatal at times. In addition, tight glucose monitoring may involve pricking the finger multiple times per day, which may prove painful and tedious. Continuous glucose monitoring (CGM) devices (Figure 1B) is another invasive technique used to monitor blood glucose level. Figure 1 Blood glucose monitoring devices. (A) Glucometer and (B) Conitnuous glucose monitor (CGM) This device consist of a disposable needle that acts as an in- vivo sensor and an external transmitter and receiver. The receiver at the receiving end displays the blood glucose level information. The receiver section consist of a potentiostat circuit, which makes the entire device bulky. This sensor can be used for up to 7 days before replacement. There have been several attempts made to design a noninvasive glucose monitoring device. Of all the attempts, the only device that was approved by U.S. Food and Drug administration (FDA) was the “GlucoWatch G2 Biographer” (Figure 2), which was designed by Cygnus Inc. However, the inconsistencies in the measurement of glucose levels as a result of perspiration Non-diabetic people Diabetic people Test Blood glucose (mg/dL) Test Blood glucose (mg/dL) Normal 79.2-110 Pre-meal 90-130 Fasting 70-100 Post-meal < 180 B A Materials for Energy, Efficiency and Sustainability: TechConnect Briefs 2016 193