Microfluidic technologies are increasingly implemented to replace manual methods in biological and biochemical sample processing. We explore the feasibility of an acoustofluidic trap for confinement of microparticle reaction substrates against continuously flowing reagents in chemical synthesis and detection applications. Computational models are used to predict the flow and ultrasonic standing wave fields within two longitudinal standing bulk acoustic wave (LSBAW) microchannels operated in the 0.5–2.0 MHz range. Glass (gLSBAW) and silicon (siLSBAW) pillar arrays comprise trapping structures that augment the local acoustic field, while openings between pillars evenly distribute the flow for uniform exposure of substrates to reagents. Frequency spectra (acoustic energy density Eac vs frequency) and model-predicted pressure fields are used to identify longitudinal resonances with pressure minima in bands oriented perpendicular to the inflow direction. Polymeric and glass particles (10- and 20-µm diameter polystyrene beads, 6 µm hollow glass spheres, and 5 µm porous silica microparticles) are confined within acoustic traps operated at longitudinal first and second half-wavelength resonant frequencies (f1,E = 575 kHz, gLSBAW; f1,E = 666 kHz; and f2,E = 1.278 MHz, siLSBAW) as reagents are introduced at 5–10 µl min−1. Anisotropic silicon etched traps are found to improve augmentation of the acoustic pressure field without reducing the volumetric throughput. Finally, in-channel synthesis of a double-labeled antibody conjugate on ultrasound-confined porous silica microparticles demonstrates the feasibility of the LSBAW platform for synthesis and detection. The results provide a computational and experimental framework for continued advancement of the LSBAW platform for other synthetic processes and molecular detection applications.
REFERENCES
1.
T. L.
Tolt
and D. L.
Feke
, “Separation of dispersed phases from liquids in acoustically driven chambers
,” Chem. Eng. Sci.
48
(3
), 527
–540
(1993
).2.
M.
Groschl
, “Ultrasonic separation of suspended particles. Part I: Fundamentals
,” Acustica
84
(3
), 432
–447
(1998
).3.
H.
Groschl
, W.
Burger
, and B.
Handl
, “Ultrasonic separation of suspended particles. Part III: Application in biotechnology
,” Acustica
84
(5
), 815
–822
(1998
).4.
J. J.
Hawkes
, W. T.
Coakley
, M.
Groschl
, E.
Benes
, S.
Armstrong
, P. J.
Tasker
, and H.
Nowotny
, “Single half-wavelength ultrasonic particle filter: Predictions of the transfer matrix multilayer resonator model and experimental filtration results
,” J. Acoust. Soc. Am.
111
(3
), 1259
–1266
(2002
).5.
J.
Reboud
, Y.
Bourquin
, R.
Wilson
, G. S.
Pall
, M.
Jiwaji
, A. R.
Pitt
, A.
Graham
, A. P.
Waters
, and J. M.
Cooper
, “Shaping acoustic fields as a toolset for microfluidic manipulations in diagnostic technologies
,” Proc. Natl. Acad. Sci. U. S. A.
109
(38
), 15162
–15167
(2012
).6.
Y. C.
Chen
, P.
Li
, P. H.
Huang
, Y. L.
Xie
, J. D.
Mai
, L.
Wang
, N. T.
Nguyen
, and T. J.
Huang
, “Rare cell isolation and analysis in microfluidics
,” Lab Chip
14
(4
), 626
–645
(2014
).7.
D.
Carugo
, T.
Octon
, W.
Messaoudi
, A. L.
Fisher
, M.
Carboni
, N. R.
Harris
, M.
Hill
, and P.
Glynne-Jones
, “A thin-reflector microfluidic resonator for continuous-flow concentration of microorganisms: A new approach to water quality analysis using acoustofluidics
,” Lab Chip
14
(19
), 3830
–3842
(2014
).8.
M. E.
Piyasena
, P. P. A.
Suthanthiraraj
, R. W.
Applegate
, A. M.
Goumas
, T. A.
Woods
, G. P.
Lopez
, and S. W.
Graves
, “Multinode acoustic focusing for parallel flow cytometry
,” Anal. Chem.
84
(4
), 1831
–1839
(2012
).9.
P.
Li
and T. J.
Huang
, “Applications of acoustofluidics in bioanalytical chemistry
,” Anal. Chem.
91
(1
), 757
–767
(2019
).10.
F.
Petersson
, A.
Nilsson
, C.
Holm
, H.
Jonsson
, and T.
Laurell
, “Continuous separation of lipid particles from erythrocytes by means of laminar flow and acoustic standing wave forces
,” Lab Chip
5
(1
), 20
–22
(2005
).11.
F.
Petersson
, L.
Aberg
, A. M.
Sward-Nilsson
, and T.
Laurell
, “Free flow acoustophoresis: Microfluidic-based mode of particle and cell separation
,” Anal. Chem.
79
(14
), 5117
–5123
(2007
).12.
M.
Wiklund
, S.
Nilsson
, and H. M.
Hertz
, “Ultrasonic trapping in capillaries for trace-amount biomedical analysis
,” J. Appl. Phys.
90
(1
), 421
–426
(2001
).13.
I.
Gralinski
, S.
Raymond
, T.
Alan
, and A.
Neild
, “Continuous flow ultrasonic particle trapping in a glass capillary
,” J. Appl. Phys.
115
(5
), 054505
(2014
).14.
Y.
Chen
, S.
Li
, Y.
Gu
, P.
Li
, X.
Ding
, L.
Wang
, J. P.
McCoy
, S. J.
Levine
, and T. J.
Huang
, “Continuous enrichment of low-abundance cell samples using standing surface acoustic waves (SSAW)
,” Lab Chip
14
(5
), 924
–930
(2014
).15.
M.
Cui
, M. M.
Binkley
, H. N.
Shekhani
, M. Y.
Berezin
, and J. M.
Meacham
, “Augmented longitudinal acoustic trap for scalable microparticle enrichment
,” Biomicrofluidics
12
(3
), 034110
(2018
).16.
P.
Li
, Z. M.
Mao
, Z. L.
Peng
, L. L.
Zhou
, Y. C.
Chen
, P. H.
Huang
, C. I.
Truica
, J. J.
Drabick
, W. S.
El-Deiry
, M.
Dao
, S.
Suresh
, and T. J.
Huang
, “Acoustic separation of circulating tumor cells
,” Proc. Natl. Acad. Sci. U. S. A.
112
(16
), 4970
–4975
(2015
).17.
S.
Oberti
, A.
Neild
, and J.
Dual
, “Manipulation of micrometer sized particles within a micromachined fluidic device to form two-dimensional patterns using ultrasound
,” J. Acoust. Soc. Am.
121
(2
), 778
–785
(2007
).18.
I.
Leibacher
, W.
Dietze
, P.
Hahn
, J. T.
Wang
, S.
Schmitt
, and J.
Dual
, “Acoustophoresis of hollow and core-shell particles in two-dimensional resonance modes
,” Microfluid. Nanofluid.
16
(3
), 513
–524
(2014
).19.
M. J.
Ruedas-Rama
, A.
Dominguez-Vidal
, S.
Radel
, and B.
Lendl
, “Ultrasonic trapping of microparticles in suspension and reaction monitoring using Raman microspectroscopy
,” Anal. Chem.
79
(20
), 7853
–7857
(2007
).20.
T.
Lilliehorn
, M.
Nilsson
, U.
Simu
, S.
Johansson
, M.
Almqvist
, J.
Nilsson
, and T.
Laurell
, “Dynamic arraying of microbeads for bioassays in microfluidic channels
,” Sens. Actuators, B
106
(2
), 851
–858
(2005
).21.
A.
Lenshof
, C.
Magnusson
, and T.
Laurell
, “Acoustofluidics 8: Applications of acoustophoresis in continuous flow microsystems
,” Lab Chip
12
(7
), 1210
–1223
(2012
).22.
M.
Evander
and J.
Nilsson
, “Acoustofluidics 20: Applications in acoustic trapping
,” Lab Chip
12
(22
), 4667
–4676
(2012
).23.
A. A.
Doinikov
, “On the radiation pressure on small spheres
,” J. Acoust. Soc. Am.
100
(2
), 1231
–1233
(1996
).24.
A. A.
Doinikov
, “Acoustic radiation interparticle forces in a compressible fluid
,” J. Fluid Mech.
444
, 1
–21
(2001
).25.
R.
Barnkob
, P.
Augustsson
, T.
Laurell
, and H.
Bruus
, “Measuring the local pressure amplitude in microchannel acoustophoresis
,” Lab Chip
10
(5
), 563
–570
(2010
).26.
J.
Friend
and L. Y.
Yeo
, “Microscale acoustofluidics: Microfluidics driven via acoustics and ultrasonics
,” Rev. Mod. Phys.
83
(2
), 647
–704
(2011
).27.
H.
Bruus
, “Acoustofluidics 7: The acoustic radiation force on small particles
,” Lab Chip
12
(6
), 1014
–1021
(2012
).28.
M.
Settnes
and H.
Bruus
, “Forces acting on a small particle in an acoustical field in a viscous fluid
,” Phys. Rev. E
85
(1
), 016327
(2012
).29.
K.
Yosioka
and Y.
Kawasima
, “Acoustic radiation pressure on a compressible sphere
,” Acustica
5
(3
), 167
–173
(1955
).30.
L. P.
Gorkov
, “Forces acting on a small particle in an acoustic field within an ideal fluid
,” Dokl. Akad. Nauk SSSR
140
(1
), 88
(1961
).31.
P.
Glynne-Jones
, C. E. M.
Demore
, C. W.
Ye
, Y. Q.
Qiu
, S.
Cochran
, and M.
Hill
, “Array-controlled ultrasonic manipulation of particles in planar acoustic resonator
,” IEEE Trans. Ultrason., Ferroelectr. Freq. Control
59
(6
), 1258
–1266
(2012
).32.
M.
Evander
, A.
Lenshof
, T.
Laurell
, and J.
Nilsson
, “Acoustophoresis in wet-etched glass chips
,” Anal. Chem.
80
(13
), 5178
–5185
(2008
).33.
P.
Hahn
and J.
Dual
, “A numerically efficient damping model for acoustic resonances in microfluidic cavities
,” Phys. Fluids
27
(6
), 062005
(2015
).34.
COMSOL Multiphysics 5.2a,
COMSOL, Inc.
, 2016
.35.
36.
A. D.
Ledbetter
, H. N.
Shekhani
, M. M.
Binkley
, and J. M.
Meacham
, “Tuning the coupled-domain response for efficient ultrasonic droplet generation
,” IEEE Trans. Ultrason., Ferroelectr. Freq. Control
65
(10
), 1893
–1904
(2018
).37.
P. B.
Allen
and D. T.
Chiu
, “Calcium-assisted glass-to-glass bonding for fabrication of glass microfluidic devices
,” Anal. Chem.
80
(18
), 7153
–7157
(2008
).38.
P. B.
Muller
, R.
Barnkob
, M. J. H.
Jensen
, and H.
Bruus
, “A numerical study of microparticle acoustophoresis driven by acoustic radiation forces and streaming-induced drag forces
,” Lab Chip
12
(22
), 4617
–4627
(2012
).39.
L. M.
Lee
, R. L.
Heimark
, J. C.
Baygents
, and Y.
Zohar
, “Self-aligned immobilization of proteins utilizing PEG patterns
,” Nanotechnology
17
(4
), S29
–S33
(2006
).40.
M.
Hill
, “The selection of layer thicknesses to control acoustic radiation force profiles in layered resonators
,” J. Acoust. Soc. Am.
114
(5
), 2654
–2661
(2003
).41.
A.
Neild
, S.
Oberti
, and J.
Dual
, “Design, modeling, and characterization of microfluidic devices for ultrasonic manipulation
,” Sens. Actuators, B
121
(2
), 452
–461
(2007
).42.
M.
Hill
, R. J.
Townsend
, and N. R.
Harris
, “Modelling for the robust design of layered resonators for ultrasonic particle manipulation
,” Ultrasonics
48
(6-7
), 521
–528
(2008
).43.
F.
Garofalo
, T.
Laurell
, and H.
Bruus
, “Performance study of acoustophoretic microfluidic silicon-glass devices by characterization of material- and geometry-dependent frequency spectra
,” Phys. Rev. Appl.
7
(5
), 054026
(2017
).44.
M.
Wu
, Y.
Ouyang
, Z.
Wang
, R.
Zhang
, P.-H.
Huang
, C.
Chen
, H.
Li
, P.
Li
, D.
Quinn
, and M.
Dao
, “Isolation of exosomes from whole blood by integrating acoustics and microfluidics
,” Proc. Natl. Acad. Sci. U. S. A.
114
(40
), 10584
–10589
(2017
).45.
S.
Li
, F.
Ma
, H.
Bachman
, C. E.
Cameron
, X.
Zeng
, and T. J.
Huang
, “Acoustofluidic bacteria separation
,” J. Micromech. Microeng.
27
(1
), 015031
(2016
).46.
M.
Wu
, C.
Chen
, Z.
Wang
, H.
Bachman
, Y.
Ouyang
, P.-H.
Huang
, Y.
Sadovsky
, and T. J.
Huang
, “Separating extracellular vesicles and lipoproteins via acoustofluidics
,” Lab Chip
19
(7
), 1174
–1182
(2019
).© 2019 Author(s).
2019
Author(s)
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