A finite-element model is presented for numerical simulation in three dimensions of acoustophoresis of suspended microparticles in a microchannel embedded in a polymer chip and driven by an attached piezoelectric transducer at MHz frequencies. In accordance with the recently introduced principle of whole-system ultrasound resonances, an optimal resonance mode is identified that is related to an acoustic resonance of the combined transducer-chip-channel system and not to the conventional pressure half-wave resonance of the microchannel. The acoustophoretic action in the microchannel is of comparable quality and strength to conventional silicon-glass or pure glass devices. The numerical predictions are validated by acoustic focusing experiments on 5-μm-diameter polystyrene particles suspended inside a microchannel, which was milled into a polymethylmethacrylate chip. The system was driven anti-symmetrically by a piezoelectric transducer, driven by a 30-V peak-to-peak alternating voltage in the range from 0.5 to 2.5 MHz, leading to acoustic energy densities of 13 J/m3 and particle focusing times of 6.6 s.

1.
E. K.
Sackmann
,
A. L.
Fulton
, and
D. J.
Beebe
, “
The present and future role of microfluidics in biomedical research
,”
Nature
507
(
7491
),
181
189
(
2014
).
2.
R.
Silva
,
P.
Dow
,
R.
Dubay
,
C.
Lissandrello
,
J.
Holder
,
D.
Densmore
, and
J.
Fiering
, “
Rapid prototyping and parametric optimization of plastic acoustofluidic devices for blood-bacteria separation
,”
Biomed. Microdev.
19
(
3
),
70
(
2017
).
3.
P.
Dow
,
K.
Kotz
,
S.
Gruszka
,
J.
Holder
, and
J.
Fiering
, “
Acoustic separation in plastic microfluidics for rapid detection of bacteria in blood using engineered bacteriophage
,”
Lab Chip
18
(
6
),
923
932
(
2018
).
4.
Y.
Gu
,
C.
Chen
,
Z.
Wang
,
P.-H.
Huang
,
H.
Fu
,
L.
Wang
,
M.
Wu
,
Y.
Chen
,
T.
Gao
,
J.
Gong
,
J.
Kwun
,
G. M.
Arepally
, and
T. J.
Huang
, “
Plastic-based acoustofluidic devices for high-throughput, biocompatible platelet separation
,”
Lab Chip
19
,
394
402
(
2019
).
5.
C.
Lissandrello
,
R.
Dubay
,
K. T.
Kotz
, and
J.
Fiering
, “
Purification of lymphocytes by acoustic separation in plastic microchannels
,”
SLAS Technol.
23
(
4
),
352
363
(
2018
).
6.
R.
Dubay
,
C.
Lissandrello
,
P.
Swierk
,
N.
Moore
,
D.
Doty
, and
J.
Fiering
, “
Scalable high-throughput acoustophoresis in arrayed plastic microchannels
,”
Biomicrofluidics
13
(
3
),
034105
(
2019
).
7.
I.
González
,
M.
Tijero
,
A.
Martin
,
V.
Acosta
,
J.
Berganzo
,
A.
Castillejo
,
M. M.
Bouali
, and
J. L.
Soto
, “
Optimizing polymer lab-on-chip platforms for ultrasonic manipulation: Influence of the substrate
,”
Micromachines
6
(
5
),
574
591
(
2015
).
8.
C.
Yang
,
Z.
Li
,
P.
Li
,
W.
Shao
,
P.
Bai
, and, and
Y.
Cui
, “
Acoustic particle sorting by integrated micromachined ultrasound transducers on polymerbased microchips
,” in
Proceedings of the 2017 IEEE International Ultrasonics Symposium (IUS)
, Washington, DC (September 6–9,
2017
).
9.
R. P.
Moiseyenko
and
H.
Bruus
, “
Whole-system ultrasound resonances as the basis for acoustophoresis in all-polymer microfluidic devices
,”
Phys. Rev. Appl.
11
,
014014
(
2019
).
10.
A.
Mueller
,
A.
Lever
,
T. V.
Nguyen
,
J.
Comolli
, and
J.
Fiering
, “
Continuous acoustic separation in a thermoplastic microchannel
,”
J. Micromech. Microeng.
23
(
12
),
125006
(
2013
).
11.
R.
Barnkob
,
P.
Augustsson
,
T.
Laurell
, and
H.
Bruus
, “
Measuring the local pressure amplitude in microchannel acoustophoresis
,”
Lab Chip
10
(
5
),
563
570
(
2010
).
12.
P.
Augustsson
,
R.
Barnkob
,
S. T.
Wereley
,
H.
Bruus
, and
T.
Laurell
, “
Automated and temperature-controlled micro-PIV measurements enabling long-term-stable microchannel acoustophoresis characterization
,”
Lab Chip
11
(
24
),
4152
4164
(
2011
).
13.
P. B.
Muller
,
M.
Rossi
,
A. G.
Marín
,
R.
Barnkob
,
P.
Augustsson
,
T.
Laurell
,
C. J.
Kähler
, and
H.
Bruus
, “
Ultrasound-induced acoustophoretic motion of microparticles in three dimensions
,”
Phys. Rev. E
88
(
2
),
023006
(
2013
).
14.
B.
Hammarström
,
M.
Evander
,
H.
Barbeau
,
M.
Bruzelius
,
J.
Larsson
,
T.
Laurell
, and
J.
Nilsson
, “
Non-contact acoustic cell trapping in disposable glass capillaries
,”
Lab Chip
10
(
17
),
2251
2257
(
2010
).
15.
A.
Lenshof
,
M.
Evander
,
T.
Laurell
, and
J.
Nilsson
, “
Acoustofluidics 5: Building microfluidic acoustic resonators
,”
Lab Chip
12
,
684
695
(
2012
).
16.
W. N.
Bodé
and
H.
Bruus
, “
Numerical study of the coupling layer between transducer and chip in acoustofluidic devices
,”
J. Acoust. Soc. Am.
149
(
5
),
3096
3105
(
2021
).
17.
W. N.
Bodé
,
L.
Jiang
,
T.
Laurell
, and
H.
Bruus
, “
Microparticle acoustophoresis in aluminum-based acoustofluidic devices with PDMS covers
,”
Micromachines
11
(
3
),
292
(
2020
).
18.
A.
Tahmasebipour
,
L.
Friedrich
,
M.
Begley
,
H.
Bruus
, and
C.
Meinhart
, “
Toward optimal acoustophoretic microparticle manipulation by exploiting asymmetry
,”
J. Acoust. Soc. Am.
148
(
1
),
359
373
(
2020
).
19.
N. R.
Skov
,
J. S.
Bach
,
B. G.
Winckelmann
, and
H.
Bruus
, “
3D modeling of acoustofluidics in a liquid-filled cavity including streaming, viscous boundary layers, surrounding solids, and a piezoelectric transducer
,”
AIMS Math.
4
,
99
111
(
2019
).
20.
J. S.
Bach
and
H.
Bruus
, “
Theory of pressure acoustics with viscous boundary layers and streaming in curved elastic cavities
,”
J. Acoust. Soc. Am.
144
,
766
784
(
2018
).
21.
M.
Settnes
and
H.
Bruus
, “
Forces acting on a small particle in an acoustical field in a viscous fluid
,”
Phys. Rev. E
85
,
016327
(
2012
).
22.
N. R.
Skov
,
P.
Sehgal
,
B. J.
Kirby
, and
H.
Bruus
, “
Three-dimensional numerical modeling of surface-acoustic-wave devices: Acoustophoresis of micro- and nanoparticles including streaming
,”
Phys. Rev. Appl.
12
,
044028
(
2019
).
23.
P. B.
Muller
and
H.
Bruus
, “
Numerical study of thermoviscous effects in ultrasound-induced acoustic streaming in microchannels
,”
Phys. Rev. E
90
(
4
),
043016
(
2014
).
24.
J. T.
Karlsen
,
P.
Augustsson
, and
H.
Bruus
, “
Acoustic force density acting on inhomogeneous fluids in acoustic fields
,”
Phys. Rev. Lett.
117
,
114504
(
2016
).
25.
J. T.
Karlsen
and
H.
Bruus
, “
Forces acting on a small particle in an acoustical field in a thermoviscous fluid
,”
Phys. Rev. E
92
,
043010
(
2015
).
26.
W.
Slie
,
A.
Donfor
, Jr.
, and
T.
Litovitz
, “
Ultrasonic shear and longitudinal measurements in aqueous glycerol
,”
J. Chem. Phys.
44
(
10
),
3712
3718
(
1966
).
27.
L.
Negadi
,
B.
Feddal-Benabed
,
I.
Bahadur
,
J.
Saab
,
M.
Zaoui-Djelloul-Daouadji
,
D.
Ramjugernath
, and
A.
Negadi
, “
Effect of temperature on density, sound velocity, and their derived properties for the binary systems glycerol with water or alcohols
,”
J. Chem. Thermodyn.
109
,
124
136
(
2017
).
28.
N.-S.
Cheng
, “
Formula for the viscosity of a glycerol-water mixture
,”
Ind. Eng. Chem. Res.
47
(
9
),
3285
3288
(
2008
).
29.
B.
Hartmann
and
J.
Jarzynski
, “
Polymer sound speeds and elastic constants
,”
Naval Ordnance Laboratory Report NOLTR 72-269
, US Naval Ordnance Laboratory, White Oak, MD,
1972
.
30.
D.
Christman
, “
Dynamic properties of poly(methylmethacrylate) (PMMA) (Plexiglas)
,”
Report No. DNA 2810F, MSL-71-24
, General Motors Technical Center, Warren, MI,
1972
.
31.
H.
Sutherland
and
R.
Lingle
, “
Acoustic characterization of polymethyl methacrylate and three epoxy formulations
,”
J. Appl. Phys.
43
(
10
),
4022
4026
(
1972
).
32.
H.
Sutherland
, “
Acoustical determination of shear relaxation functions for polymethyl methacrylate and Epon 828-Z
,”
J. Appl. Phys.
49
(
7
),
3941
3945
(
1978
).
33.
J.
Carlson
,
J.
van Deventer
,
A.
Scolan
, and, and
C.
Carlander
, “
Frequency and temperature dependence of acoustic properties of polymers used in pulse-echo systems
,” in
Proceedings of the IEEE Symposium on Ultrasonics, 2003
, Honolulu, HI (October 5–8,
2003
), Vol.
1
, pp.
885
888
.
34.
A.
Simon
,
G.
Lefebvre
,
T.
Valier-Brasier
, and
R.
Wunenburger
, “
Viscoelastic shear modulus measurement of thin materials by interferometry at ultrasonic frequencies
,”
J. Acoust. Soc. Am.
146
(
5
),
3131
3140
(
2019
).
35.
H. T.
Tran
,
T.
Manh
,
T. F.
Johansen
, and
L.
Hoff
, “
Temperature effects on ultrasonic phase velocity and attenuation in Eccosorb and PMMA
,” in
Proceedings of the 2016 IEEE International Ultrasonics Symposium (IUS)
, Tours, France (September 18–21,
2016
), pp.
1
4
.
36.
P.
Hahn
and
J.
Dual
, “
A numerically efficient damping model for acoustic resonances in microfluidic cavities
,”
Phys. Fluids
27
,
062005
(
2015
).
37.
COMSOL Multiphysics
5.5 (
2019
), http://www.comsol.com (Last viewed 7 May 2021).
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
,
4617
4627
(
2012
).
39.
M.
Bora
and
M.
Shusteff
, “
Efficient coupling of acoustic modes in microfluidic channel devices
,”
Lab Chip
15
(
15
),
3192
3202
(
2015
).
40.
See supplementary material at https://www.scitation.org/doi/suppl/10.1121/10.0005113 for four animations of the simulated 1.17-MHz mode shown in Fig. 3 and one video of the experimental particle focusing corresponding to Fig. 6.
41.
R.
Barnkob
,
I.
Iranmanesh
,
M.
Wiklund
, and
H.
Bruus
, “
Measuring acoustic energy density in microchannel acoustophoresis using a simple and rapid light-intensity method
,”
Lab Chip
12
,
2337
2344
(
2012
).

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