MEMS design and Micro-fabrication Lab

1. 2-Dimensional SPR Detection System Integrated with Molecular Imprinting Polymer Microarrays Using Microfluidic Technology Kuo-Hoong Lee, Yuan-Deng Su, Shean-Jen Chen and Gwo-Bin Lee Department of Engineering Science, National Cheng Kung University, Tainan, Taiwan 701 Abstract This study reports a novel microfluidic chip integrated with arrayed molecular imprinting polymer (MIP) films for surface plasmon resonance (SPR) phase imaging of specific bio-samples. The SPR imaging system uses a surface-sensitive optical technique to detect two-dimensional spatial phase variation caused by bio-molecules absorbed on a sensing surface composed of highly-specific MIP films. The developed system has a high resolution and a high-throughput screening capability and has been successfully applied to the analysis of multiple bio-molecules without the need for additional labeling in long-term measuring. Results Design (a) A SPR/MIP microfluidic chip comprising microchannels, micropumps/microvalves, micro-heaters and temperature sensors coupled with a 2-D SPR imaging system was developed. Micropumps were used to automate the sample injection. A micromachine-based temperature control module comprised of micro-heaters and a temperature sensor was used to maintain the temperature during measurement. (b) The temperature control system can heated up bio-samples to 37 °C within 20s and kept them at a uniform temperature. (a) Schematic illustration of the arrayed SPR/MIP microfluidic chip (b) Cross-sectional view showing that three layers of PDMS could be used to transport samples from inlet to outlet through the arrayed MIP films. Fabrication The relationship between the pumping rate and the driving frequency. SEM images of the SU-8 molds (a and c) and PDMS replicas (b and d) of the arrayed MIP reactors and micropumps/valves. (e) the temperature sensor and heater. Simplified fabrication process of the SPR/MIP microfluidic chip. (a) SU-8 molding and PDMS casting fabrication process; (b) Spin-coating of MIP films and polymerization process; (c) Temperature sensor and heaters fabricated by using lift-off technique. (a) (b) (a) SPR phase interference image and (b) phase reconstructed image when ethanol flows through the arrayed MIP films. Conclusions A novel SPR/MIP microfluidic chip integrated with arrayed MIP films for SPR phase imaging of specific bio-samples was developed. Multiple MIP films could be used for highly-sensitive, highly-specific bio-sensing. The development of the SPR/MIP microfluidic chip can be promising for nano-sensing applications and can detect bio-samples with a low molecular weight. Acknowledgements The authors gratefully acknowledge the financial support provided to this study by the MOE Program for Promoting Academic Excellence of Universities (Grant number EX- A-91-E-FA08-1-4). The detection kinetics of 50 μM progesterone. Reaction procedure (0 ~ 21 min : ethanol, 21 ~ 126 min : ethanol + 50μM progesterone, 126 min ~ : ethanol). 2006 MML MEMS design and Micro-fabrication Lab