An Injectable Glucose Biosensor Based on a Self-cleaning Membrane & NIR FRET Assay

Texas A&M Engineering Experiment Station, College Station TX

Investigators

Abstract

Diabetes affects millions of people in the United States. To avoid serious health risks, blood sugar must be measured and kept at normal levels. Continuous blood sugar monitors are used to replace finger prick tests. This allows measurement of sugar levels both day and night. Current continuous sugar monitors use a small sensor probe like a wire that is inserted through the skin. This is usually put in the arm and is replaced about every two weeks. A transmitter is put on the skin over the sensor to communicate to a smartphone. This research seeks to develop a sugar sensor that is easier to use. The sensor will be the size of a grain of rice. This small size allows it to be injected into the tissue of the wrist with a needle. Then the sugar levels can be comfortably monitored with a device like a watch. This new sensor is expected to last 30 days or more. It will be sensitive to the change in the sugar like current sensors. It will also be convenient to use. This research will also provide training experiences to high school students and university students. This project seeks to develop a grain-of-rice size, injectable glucose biosensor to enable continuous monitoring with a wearable device. This will be accomplished by addressing challenges related to biocompatibility and optical glucose sensing through innovative biomaterials and assay chemistries, respectively. The scientific objectives include: (1) Develop an injectable biosensor comprised of a self-cleaning membrane and a near-infrared (NIR) fluorescence glucose sensing assay and sealing the assay within the membrane’s central cavity with self-closing caps. (2) Develop a wearable optical detection system to interrogate the biosensor and measure glucose levels (comprised of an LED and photodiode pair, without the need for an affixed transmitter). (3) Assess the biosensor’s ability to monitor glucose levels in vivo (rat model), as well as the membrane’s reduction of the foreign body reaction (FBR). Beyond allowing non-surgical injection, such a biosensor design affords convenient, non-invasive detection exclusively with a watch-like device The NIR fluorescence optical sensing is expected to enable glucose detection for individuals of all skin tones and body mass indices (BMIs). The results of this work are poised to have broad impact in the development of other implantable biosensors and devices. The self-cleaning membrane will advance knowledge in the role of active mechanisms rather than passive mechanisms for biofouling control, and hence improved biocompatibility. The NIR fluorescence assay will advance the knowledge of optical sensing methods that achieve exceptional in vitro stability, reversibility, dynamic range, and sensitivity. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.