Integrated Microfluidic Systems for Automatic Glucose Sensing and

Integrated Microfluidic Systems for Automatic Glucose Sensing and Insulin Injection 1 Chao-June Huang, 2 Chih-Hao Wang, 3 Yi-Hsin Chen, 3 Tse-Chuan Chou and, 1, 2 Gwo-Bin Lee, 4 Xi-Zhang Lin, and 4 Ming-Hua Chen 1 Institute of Micro-Electro-Mechanical-System Engineering, 2 Department of Engineering Science, 3 Department of chemical engineering, 4 Department of Internal Medicine 1 National Cheng Kung University 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 online monitoring of human glucose concentration and precise injection of proper doses of insulin to maintain a stable blood glucose concentration. Results Design Pumping rate (μl/min) 30 psi 4 20 psi Frequency (Hz) The relationship between pumping rate and driving frequency for different working pressures. Lower substrate 1. SU-8 spin coating 1. PR patterning 3 25 psi Fabrication Upper substrate 2 2. Photolithography 2. Ag deposition A series of photographs showing that insulin samples could be successfully injected using the developed micro-pumps through a stick needle. blood sugar concentration (mg/d. L) Schematic representation of the Microfluidic GSII (Glucose sensing and insulin injection) biochip (top-view). 1 3. PDMS casting 3. Lift off time (min) 4. 02 Plasma treatmnet and bonding 4. Au/Pt deposition : Ag : Pt : Au : Glass Bonding : Silicon : PDMS Output current of the glucose sensor at various glucose concentrations. : SU-8 A simplified fabrication process for the Microfluidic chip. Polyprrole GOD 1. Pyrrole 0. 05 M & GOD 0. 5 mg/ml with 0. 1 M KCl. 2. Applied current 4. 584 u. A for 130 s on Pt. Working electrode : Pt Glucose injection H 2 O 2 3. Sink in P. B. S as blank phase. When electrode stable inject glucose. 4. GOD oxide glucose 5. Produce H 2 O 2 6. Sensing at 700 m. V vs. Ag/Ag. Cl A simplified fabrication process for the working electrode. Glucose response after injection of 0. 3 cc insulin in a mouse body 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 m. M can be detected. The sensitivity of the glucose sensor is measured to be 0. 99 n. A/m. M • The sensitivity is comparable to large-scale traditional detection system. • The sample consumptions of the proposed chip device is less than 30μL 2006 MML MEMS design and Micro-fabrication Lab