Abstract

1. Amperometric Real Time In-Vivo Enzyme Sensors for Physiological Monitoring of Birds Engineering Learning Initiatives Abdurrahman Gumus (ag598@cornell.edu), Nipun Jasuja (nj57@cornell.edu)and David Erickson (de54@cornell.edu) Integrated Micro- and Nanofluidic Systems Laboratory Sibley School of Mechanical and Aerospace Engineering, Cornell University Methods: Uric Acid Sensor Chemistry Abstract Researchers from Cornell University and the Cornell Lab of Ornithology aim to develop self-reliant, self-powered microsystems for autonomous biophysical monitoring. These systems will be applied to the understanding of avian flight biology through the development of a “Lab-on-a-Bird”. As a part of this project, needle-type biosensors developed by Endo et al. [1] to detect glucose levels in fish were replicated. A working electrode was created using a platinum-iridium wire, and glucose oxidase was the enzyme used to coat the working electrode. A 650 mV potential was applied between the working electrode and the reference electrode (Ag/AgCl paste). The results obtained were comparable to the literature value. These sensors are currently being extended and modified so that they can detect the desired blood metabolites like uric acid in birds. Background and Motivation Electrode under SEM Sensor Schematic • As sensors become increasingly small, miniaturization of the platforms that carry them into the environment has lagged behind. The primary impact of this project will be the development of • an integrated and autonomous microsystem technology that can enable this. • The second area of impact will be in avian biology. At present, almost nothing is known about • changes in the biochemistry of individual birds over the course of their annual. Such devices • could lead to an entirely new way of studying avian behavior. • A 650 mV potential (vs. Ag/AgCl) is applied by the potentiostat to the Pt/Ir working electrode for the amperometric uric acid measurement • Uricasecatalysesuric acid as follows: • Uric Acid+ O2 Gluconic Acid + H2O2 • Hydrogen Peroxide is reduced on the surface when the potential is applied: • H2O2 O2 + 2H+ +2e- Uricase Current Avian Monitoring RF tag. Tag shown here is similar to the one shown attached to the Red Knot Red knot with solar geo-location transceiver Potential Objectives Experimental Results • Fabricate and modify glucose-detecting biosensors • developed by Endo et al. [1, 2] • Extend the number of metabolites which can be detected to include uric acid and beta-hydroxybutyrate • Develop a microfabrication compatible nanowire based • sensor system which can increase the sensitivity of • current devices. Methods: Sensor Fabrication Glucose Calibration Curve Uric Acid Calibration Curve (without enzyme) Uric Acid Calibration Curve (with UOx enzyme) Start with a platinum/iridium wire that is coated with Teflon Strip the Teflon at one end Wrap the remaining Teflon in silver wire Conclusion and Future Work Needle type biosensors for amperometric measurement of glucose and were successfully fabricated. Initial results from sensors modified for amperometric measurement of uric acid are also positive. We are currently working on improving our design for uric acid sensors and integrating the sensors with microcontrollers and electronics to effectively store and transmit data. Efforts will then be made towards the fabrication of a nanowire based metabolite sensor. 1 cm Solder lead wires to the Pt/Ir and Cu to connect to potentiometer The exposed Pt/Ir end is covered by nafion and then an enzyme membrane appropriate for the desired test. Apply silver/silver chloride paste to copper wire Acknowledgements & References [1] Endo, H. et. al. “Wireless enzyme sensor system for real-time monitoring of blood glucose levels in fish” Biosensors and Bioelectronics 24 (2009) 1417 - 1423 [2] Endo, H. et. al. “Wireless monitoring of blood glucose levels in flatfish with a needle biosensor” Fish Sci 76 (2010) 687 - 694 [3] Hoshi, T. et. al. “Amperometric uric acid sensors based on polyelectrode multilayer films” Talanta 61 (2003) 00303-5 .