This paper presents the experimental investigations of droplet movement driven by focused surface acoustic waves (SAWs) generated by a circular-arc interdigital transducer (CIDT). Surface acoustic waves propagating through a droplet in contact with the substrate exerted an acoustic streaming force on the droplet, as demonstrated by numerical modeling in this study. Different from the straight droplet movement driven by a straight interdigital transducer (SIDT), the droplets were focused to the center region of the CIDT. In addition, the droplets driven by the CIDT moved much faster than those driven by the SIDT with an identical input power because of the concentrated acoustic energy in the CIDT. Merging of two moving droplets using the CIDT was also demonstrated. The present results show that focused SAWs can be more efficient than uniform SAWs for droplet and fluid actuation in microfluidics.
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Banerjee AN, Qian S, Joo SW (2011) High-speed droplet actuation on single-plate electrode arrays. J Colloid Interface Sci 362(2):567–574
Bennes J, Alzuaga S, Cherioux F, Ballandras S, Vairac P, Manceau JF, Bastien F (2007) Detection and high-precision positioning of liquid droplets using SAW systems. IEEE Trans Ultrason Ferroelectr Freq Control 54(10):2146–2151
Bennes J, Ballandras S, Cherioux F (2008) Easy and versatile functionalization of lithium niobate wafers by hydrophobic trichlorosilanes. Appl Surf Sci 255(5):1796–1800
Brouzes E, Medkova M, Savenelli N, Marran D, Twardowski M, Hutchison JB, Rothberg JM, Link DR, Perrimon N, Samuels ML (2009) Droplet microfluidic technology for single-cell high-throughput screening. Proc Nat Acad Sci USA 106(34):14195–14200
Brunet P, Baudoin M, Matar OB, Zoueshtiagh F (2010) Droplet displacements and oscillations induced by ultrasonic surface acoustic waves: a quantitative study. Phys Rev E 81(3):036315
Campbell JJ, Jones WR (1968) A method of estimating optical crystal cuts and propagation directions for excitation of piezoelectric surface waves. IEEE Trans Sonics Ultrason 15(4):209–217
Cecchini M, Girardo S, Pisignano D, Cingolani R, Beltram F (2008) Acoustic-counterflow microfluidics by surface acoustic waves. Appl Phys Lett 92(10):104103
Fair R (2007) Digital microfluidics: is a true lab-on-a-chip possible? Microfluid Nanofluid 3(3):245–281
Fang SR, Zhang SY, Lu ZF (1989) SAW focusing by circular-arc interdigital transducers on YZ-LiNbO3. IEEE Trans Ultrason Ferroelectr Freq Control 36(2):178–184
Friend J, Yeo L (2010) Using laser Doppler vibrometry to measure capillary surface waves on fluid–fluid interfaces. Biomicrofluidics 4(2):026501
Friend J, Yeo LY (2011) Microscale acoustofluidics: microfluidics driven via acoustics and ultrasonics. Rev Mod Phys 83(2):647–704
Groschl M (1998) Ultrasonic separation of suspended particles: Part I: Fundamentals. Acustica 84(3):432–447
Huebner A, Srisa-Art M, Holt D, Abell C, Hollfelder F, Demello AJ, Edel JB (2007) Quantitative detection of protein expression in single cells using droplet microfluidics. Chem Commun 12:1218–1220
Masini L, Cecchini M, Girardo S, Cingolani R, Pisignano D, Beltram F (2010) Surface-acoustic-wave counterflow micropumps for on-chip liquid motion control in two-dimensional microchannel arrays. Lab Chip 10(15):1997–2000
Pollack MG, Shenderov AD, Fair RB (2002) Electrowetting-based actuation of droplets for integrated microfluidics. Lab Chip 2(2):96–101
Renaudin A, Tabourier P, Zhang V, Camart JC, Druon C (2006) SAW nanopump for handling droplets in view of biological applications. Sensors Actuators B Chem 113(1):389–397
Renaudin A, Sozanski J-P, Verbeke B, Zhang V, Tabourier P, Druon C (2009) Monitoring SAW-actuated microdroplets in view of biological applications. Sensors Actuators B Chem 138(1):374–382
Schmid L, Wixforth A, Weitz D, Franke T (2012) Novel surface acoustic wave (SAW)-driven closed PDMS flow chamber. Microfluid Nanofluid 12(1):229–235
Shi JJ, Yazdi S, Lin SCS, Ding XY, Chiang IK, Sharp K, Huang TJ (2011) Three-dimensional continuous particle focusing in a microfluidic channel via standing surface acoustic waves (SSAW). Lab Chip 11(14):2319–2324
Shilton R, Tan MK, Yeo LY, Friend JR (2008) Particle concentration and mixing in microdrops driven by focused surface acoustic waves. J Appl Phys 104(1):014910
Shiokawa S, Matsui Y, Ueda T (1989) Liquid streaming and droplet formation caused by leaky Rayleigh-waves. In: Proceedings of IEEE 1989 ultrasonics symposium, vols 1, 2, pp 643–646
Tan MK, Friend JR, Yeo LY (2009) Interfacial jetting phenomena induced by focused surface vibrations. Phys Rev Lett 103(2):024501
Tan MK, Friend JR, Matar OK, Yeo LY (2010) Capillary wave motion excited by high frequency surface acoustic waves. Phys Fluids 22(11):112112
Teh SY, Lin R, Hung LH, Lee AP (2008) Droplet microfluidics. Lab Chip 8(2):198–220
Trung-Dung L, Vinh-Nguyen P, Nam-Trung N (2011) High-throughput micromixers based on acoustic streaming induced by surface acoustic wave. Microfluid Nanofluid 10(3):619–625
Wixforth A, Strobl C, Gauer C, Toegl A, Scriba J, von Guttenberg Z (2004) Acoustic manipulation of small droplets. Anal Bioanal Chem 379(7–8):982–991
Yeo LY, Friend JR (2009) Ultrafast microfluidics using surface acoustic waves. Biomicrofluidics 3(1):012002
Zhang AL, Wu ZQ, Xia XH (2011) Transportation and mixing of droplets by surface acoustic wave. Talanta 84(2):293–297
This work was supported from the National Center for Research Resources and the National Institute of General Medical Sciences of the National Institutes of Health through Grant Number P41 RR01315, the National Flow Cytometry Resource. This work was performed, in part, at the Center for Integrated Nanotechnologies, a US Department of Energy, Office of Basic Energy Sciences user facility and the authors gratefully acknowledge Mr. Jon Kevin Baldwin for the assistance of Cr/Au deposition. Los Alamos National Laboratory, an affirmative action equal opportunity employer, is operated by Los Alamos National Security, LLC, for the National Nuclear Security Administration of the US Department of Energy under contract DE-AC52-06NA25396.
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Ai, Y., Marrone, B.L. Droplet translocation by focused surface acoustic waves. Microfluid Nanofluid 13, 715–722 (2012). https://doi.org/10.1007/s10404-012-0990-y
- Surface acoustic wave (SAW)
- Interdigital transducer (IDT)
- Acoustic streaming
- Droplet manipulation