Integrated Microfluidic Systems for Automatic Glucose Sensing and Insulin Injection

1. Integrated Microfluidic Systems for Automatic Glucose Sensing and Insulin Injection 1Chao-June Huang, 2Chih-Hao Wang, 3Yi-Hsin Chen, 3Tse-Chuan Chou and, 1,2Gwo-Bin Lee, 4Xi-Zhang Lin, and 4Ming-Hua Chen 1Institute of Micro-Electro-Mechanical-System Engineering, 2Department of Engineering Science, 3Department of chemical engineering, 4Department of Internal Medicine1 National Cheng Kung University 30 psi 25 psi Lower substrate Upper substrate Polyprrole GOD 2 1 20 psi 1.SU-8 spin coating 1.PR patterning Pumping rate (μl/min) 2.Photolithography 2.Ag deposition 3.PDMS casting Working electrode :Pt 3.Lift off 3 4 H2O2 Glucose injection 4.02 Plasma treatmnet and bonding 4.Au/Pt deposition : Ag : Silicon Bonding : Pt : PDMS : Au : SU-8 : Glass Frequency (Hz) Abstract This study presents a new Microfluidic system capable of real-time glucose measurement and automatic insulin injection. The hand-held system used MEMS (Micro-Electro -Mechanical-Systems) techniques, which integrated micro-pumps, micro-valves, microchannels, needles and glucose sensing electrodes on a small chip. Glucose monitoring was performed in a process including blood sample collection, glucose concentration detection, and injection of insulin. Micro-pumps and micro valves were used to automate the whole process in this single chip. Preliminary data showed that the developed chip could successfully detect the glucose concentration and inject a specific amount of insulin through the needles. The developed system could be promising for on-line monitoring of human glucose concentration and precise injection of proper doses of insulin to maintain a stable blood glucose concentration. Results Design A series of photographs showing that insulin samples could be successfully injected using the developed micro-pumps through a stick needle. The relationship between pumping rate and driving frequency for different working pressures. Schematic representation of the Microfluidic GSII (Glucose sensing and insulin injection) biochip (top-view). Fabrication blood sugar concentration (mg/dL) time (min) Glucose response after injection of 0.3cc insulin in a mouse body Output current of the glucose sensor at various glucose concentrations. Conclusions • This study presented a MEMS-based Microfluidic system capable of performing the measurement of the glucose concentration and the insulin injection in an automatic and real-time fashion. • Experimental results showed the glucose concentrations ranging from 1.61 to 30 mM can be detected. The sensitivity of the glucose sensor is measured to be 0.99 nA/mM • The sensitivity is comparable to large-scale traditional detection system. • The sample consumptions of the proposed chip device is less than 30μL A simplified fabrication process for the Microfluidic chip. • Pyrrole 0.05M & GOD 0.5mg/ml with 0.1M KCl. • Applied current 4.584uA for 130s on Pt. • Sink in P.B.S as blank phase. When electrode stable inject glucose. • GOD oxide glucose • Produce H2O2 • Sensing at 700mV vs. Ag/AgCl 2006 MML MEMS design and Micro-fabrication Lab A simplified fabrication process for the working electrode.