NSC 892218E006071 1
Preparation of NSC Project Reports microfluidic channels are fabricated on quartz substrates and then used to imprint microstructures into Polymethylmethacrylate (PMMA) substrates using hot embossing methods. At last, The flow switching is verified experimentally with the use of --(1) hydrodynamic pre-focusedmicroscopic visualization of water sheath flows and (2) (valveless switch) dye-containing sample flow. Experimental data indicate that the sample flow could be (output-port) hydrodynamically pre-focused and then guided into a, desired outlet port based on relative sheath and sample flow rates. The added pre-focused function prior to flow switching is crucial for precise sample injection. CFDRC The microfluidic chip could be applied in the fields of bio/chemical analysis. one-mask 1980 PMMA Micro-Electro-Mechanical-System sheath flows MEMS sample flow sample flow flow-rate-ratio [1,2] Abtract The paper investigates a novel microfluidic chip capable of continuous sample switching and injection (CFD) µ-fc for bio-analytical applications. The novel device integrates two important microfluidic phenomena, (Micromachining including hydrodynamic focusing and valveless flow (flow focusing) (flow guiding) switching inside multi-ported micro-channels. In this µ-fc µ-fcµ-ce study, a simple theoretical model based on flow-rate-ratio method is first proposed to predict the performance of the device. Based on these data, a pre-focused 1xN flow switch is designed and fabricated using micromachining techniques. A novel 1 micromachining technique combining quartz template sample flow 17 fabrication and replication of microstructures on PMMA substrates for mass production of the sheath flows sample microfluidic devices is demonstrated. flow sample Three-dimensional templates with inverse image of 2
flow hydrodynamic pre-focused (sample) sample flow (smearing) sample flow 1 sheath flows sample flow 7 5 flow-rate-ratio 6 (1) (,OLYMPUS) hydrodynamic pre-focused section (2) (dispenser section) (flow cytometer) (syringe pump) 2 (sheath flow) 13 2 (sample flow) 0.2 mm/s (sheath flow) Chromium,Cr 0.05 mm/s 1.4 mm/s (sheath flow) BOE, 61 (sample flow) (flow-rate-ratio) 2.5 70 BOE (hydrofluoric acid, HF) hydrodynamic pre-focused PMMA (smearing PMMA problem) Bonding (sample flow) BC( 3 7a) 8b 8 (sample flow) (sample flow) hydrodynamic pre-focused (sample flow) [7,8] (3) ~ (9) 9 CFDRC-GEOM &ACE(U) v6.2 (sheath flow) (sample (sample flow) 1. Newtonian fluid steady 20m state (sample flow) 2. 3. 4. no slip conditions 5. particle trajectories high-throughput microfludic systems [3] hydrodynamic pre-focused (valveless switch) 1N (output-port) (sample flow) 3
(smearing problem) continuous sample introduction and separation (potential flow theory) functions, International Symposium on Smart hydrodynamic pre-focused (sample Structures and Microsystems (IS3M), Hong Kong, October 19-21, pp. 113-120, (2000). flow) (valveless switch) 9. G. T. A. Kovacs, Micromachined Transducers Sourcebook, McGraw-Hill Inc. (1998). 10. H. Nakanishi, T. Nishimoto, R. Nakamura, A. (flow-rate-ratio) sheath Yotsumoto, and S. Shoji, Studies on flows sample flow SiO2-SiO2 Bonding with Hydrofluoric Acid Room Temperature and Low Stress Bonding Technique for MEMS, Proc. of IEEE hydrodynamic pre-focused MEMS 98, Heidelberg, Germany, pp. 609-614, (1998). (flow-rate-ratio) Pre-focused region Dispenser region hydrodynamic pre-focused (smearing problem) A B v 1 1 1. Gert Blankenstein, Ulrik D. Larsen Modular concept of a laboratory on a chip for chemical and biochemical analysis Biosensors & Bioelectronics v13 no3-4 pp. 427-438 (1998). 2. Pieter Telleman, Ulrik D. Larsen, John Philip Cell sorting in microfluidic systems µ TAS98 pp. 39-44 (1998). 3. G. B. Lee, C. I. Hung, B. J. Ke, G. R. Huang, and B.H. Hwei, Hydrodynamic Focusing for a Micromachined Flow Cytometer, submitted to ASME Journal of Fluids Engineering, (2000). 4. Van Doormaal J. P., Raithby G. D., Enhancements of the SIMPLE method for predicting incompressible fluid flows Numerical Heat Transfer, vol 7, pp.147-163 (1984). 5. G. Blankenstein, L.Scampavia, J. Branebjerg, U. D. Larsen, and J. Ruzicka, Flow Switch for Analyte Injection and Cell/Particle Sorting, Proceedings of the 2nd International Symposium on Miniaturized Total Analysis Systems, µ-tas 96, Basel Switzerland, Nov. 19-22, pp. 82-84.(1996) 6. G. Blankenstein, and U. D. Larsen, Modular Concept of a Laboratory on a Chip for Chemical and Biochemical Analysis, Biosensors & Bioelectronics, vol. 13, No. 3-4, pp. 427-438.(1998) 7. G. B. Lee, C. I. Hung, B. J. Ke, G. R. Huang, B. H. Hwei, Micromachined Pre-Focused 1x N Flow Switch, submitted to Journal of Micromechanics and Microengineering,( 2001). 8.. G. B. Lee, C. I. Hung, B. J. Ke, G. R. Huang, B. H. Hwei, Y. H. Lin, W. Y. Wu, Development of high-throughput microfluidic chips with v 2 v 3 D2 D3 L1 v c 1 sample flow 17 (1) Lithography (2) PR developing (3) Cr etching (4) PR stripping (5)quartz etching Photomask Deep UV Da L2 PR Cr C D E F G quartz 2 L3 4
6 (sample flow) B C 3 40m (a) (e) 2 10 6 3.6 1.2 0.6 0.7 2.8 1 (b) (f) Unit : mm 417 CCD Computer Pin hole Emission filter mirror Light source (c) (g) Syringe pump 5 1 V 2 (d) 717 V 3 (a) (b) 5
100 experimental data A B C v 3 / v 2 80 60 40 20 0 D E F G 0 20 40 60 80 100 v 1 / v 2 8 v 1 sheath flow D 1 D a d v 2 sample flow D 2 v c v 3 sheath flow D 3 9 6