Yongquan Wang*a , Jingyuan Wangb, Hualing Chenc
School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi, 710049, P. R. China
a email@example.com,, firstname.lastname@example.org,, c email@example.com,
This paper presents the fabrication of a novel micro-machined cytometric device, and the experimental investigations for its 3D hydrodynamic focusing performance. The proposed device is simple in structure, with the uniqueness that the depth of its microchannels is non-uniform. Using the SU-8 soft lithography containing two exposures, as well as micro-molding techniques, the PDMS device is successfully fabricated. Two kinds of experiments, i.e., the red ink fluidity observation experiments and the fluorescent optical experiments, are then performed for the device prototypes with different step heights, or channel depth differences, to explore the influence laws of the feature parameter on the devices hydrodynamic focusing behaviors. The experimental results show that the introducing of the steps can efficiently enhance the vertical focusing performance of the device. At appropriate geometry and operating conditions, good 3D hydrodynamic focusing can be obtained.
이 논문은 새로운 마이크로 머신 세포 측정 장치의 제조와 3D 유체 역학적 초점 성능에 대한 실험적 조사를 제시합니다. 제안 된 장치는 구조가 단순하며, 마이크로 채널의 깊이가 균일하지 않다는 독특함이 있습니다. 두 가지 노출이 포함 된 SU-8 소프트 리소그래피와 마이크로 몰딩 기술을 사용하여 PDMS 장치가 성공적으로 제작되었습니다. 그런 다음 두 종류의 실험, 즉 적색 잉크 유동성 관찰 실험과 형광 광학 실험을 단계 높이 또는 채널 깊이 차이가 다른 장치 프로토 타입에 대해 수행하여 장치 유체 역학적 초점에 대한 기능 매개 변수의 영향 법칙을 탐색합니다. 행동. 실험 결과는 단계의 도입이 장치의 수직 초점 성능을 효율적으로 향상시킬 수 있음을 보여줍니다. 적절한 형상과 작동 조건에서 우수한 3D 유체 역학적 초점을 얻을 수 있습니다.
Flow cytometer, Hydrodynamic focusing, Three-dimensional (3D), Micro-machined
In this paper, we presented a novel micro-machined cytometric device and its fabrication process,
emphasizing on the experimental investigations for its 3D hydrodynamic focusing performance. The
proposed device is simple in structure, low cost, and easy to be batch produced. Besides this, as a
device based on standard micro-fabrication methodology, it can be conveniently integrated with other
micro-fluidic and/or micro-optical units to form a complete detection and analysis system.
The experimental tests for the prototype devices not only verified the design conception, but also
gave us a comprehensive understanding of the device hydro-focusing performance. The experimental
results show that, as the uniqueness of this design, the introducing of the feature steps can
significantly enhance the vertical focusing performance of the devices, which is crucial for the
achievement of 3D focusing. In summary, for the proposed novel device, good 3D hydrodynamic
focusing can be attained at appropriate geometry and operating conditions.
In addition, an improved design can be obtained by replacing the flat cover with an identical
device unit, in other words, the same two device units are bonded together (The channels are inward
and aligned) to form a new device. Then the sample stream can focused to the center of the assembly
outlet channel due to the hydrodynamic forces equally in both horizontal and vertical directions, and
thus avoiding the adsorption or friction issues of cells/particles to the top channel wall.
 Mandy FF, Bergeron M, Minkus T, Principles of flow cytometry. Transfusion Science Transfusion Science, 16 (1995) 303.
 Rieseberg M, Kasper C, Reardon KF, and Scheper T, Flow cytometry in biotechnology, Appl. Microbiol. Biotechnol. 56 (2001) 350.
 Chung TD, Kim HC, Recent advances in miniaturized microfluidic flow cytometry for clinical use. Electrophoresis, Electrophoresis. 28(2007) 4511.
 Xuan X, Zhu J, Church C, Particle focusing in microfluidic devices, Microfluid Nanofluid. 9(2010) 1-16.
 Stone H A, Stroock A D and Ajdari A, Engineering flows in small devices: Microfluidics toward a lab-on-a-chip, Annu. Rev. Fluid Mech. 36 (2004) 381-411.
 Fu LM, Yang RJ, Lin CH, Pan YJ, and Lee GB, Electrokinetically-driven microflow cytometers with integrated fiber optics for on-line cell/particle collection, Analytica Chimica Acta. 507(2004) 163-169.
 Applegate Jr RW, Schafer DN, Amir W, Squier J, Vestad T, Oakey J and Marr DWM, Optically integrated microfluidic systems for cellular characterization and manipulation, J. Opt. A: Pure Appl. Opt. 9(2007) 122-128.
 Chang CM, Hsiung SK, Lee GB, Micro flow cytometer chip integrated with micro-pumps/micro-valves for multi-wavelength cell counting and sorting, Jpn. J. Appl. Phys. 46 (2007): 3126-3134.
 Lee GB, Hung CI, Ke BJ, Huang GR, Hwei BH, and Lai Hui-Fang, Hydrodynamic focusing for a micromachined flow cytometer, J Fluids Engineering 123(2001) 672-679.
 Weigl BH, Bardell R, Schulte T, Battrell F and Hayenga J, Design and rapid prototyping of thin-film laminate-based microfluidic devices, Biomed Microdevices. 3(2001) 267-274.
 Yang AS, Hsieh WH, Hydrodynamic focusing investigation in a micro-flow cytometer, Biomed Microdevices, 9(2007) 113-122.
 Ateya DA, Erickson JS, Howell PB Jr, Hilliard LR, Golden JP, Ligler FS, The good, the bad, and the tiny: a review of microflow cytometry, Anal Bioanal Chem. 391(2008) 1485-1498.
 Goranovic G, Perch-Nielsen I, Larsen UD, Wolff A, Kutter J and Telleman P, Three-Dimensional Single Step Flow Sheathing in Micro Cell Sorters, Proceedings of MSM Conference. (2001) pp.242-245.
 Lin CH, Lee GB, Fu LM, and Hwey BH, Vertical focusing device utilizing dielectrophoretic force and its application on mocroflow cytometer, J. Microelectromech. Syst. 13 (2004) 923-932.
 Yang R, Feeback DL, Wang W, Microfabrication and test of a three-dimensional polymer hydro-focusing unit for flow cytometry applications, Sens. Actuat. A. 118(2005) 259-267.
 Hairer G, Pärr GS, Svasek P, Jachimowicz A, and Vellekoop MJ, Investigations of micrometer sample stream profiles in a three-dimensional hydrodynamic focusing device, Sens. Actuat. B. 132 (2008) 518-524.
 Mao X, Lin SC, Dong C, and Huang TJ, Single-layer planar on-chip flow cytometer using microfluidic drifting based three-dimensional (3D) hydrodynamic focusing, Lab Chip. 9 (2009) 1583-1589.
 Wang Y, Wang J, Chen H, Zhu Z, and Wang B, Prototype of a novel micro-machined cytometer and its 3D hydrodynamic focusing properties, Microsyst. Technol. 18(2012) 1991-(1997).