Acoustic trapping is used in modern biophysics laboratories to study cell adhesion or aggregation, to sort particles, or to build model tissues. Here, we create an acoustic trapping setup in liquid for an undergraduate instructional laboratory that is low-cost, easy to build, and produces results in a 1-hour laboratory period. In this setup, we use a glass slide, cover slip, and double-sided tape to make the sample chamber. A piezo-electric transducer connected to a function generator serves as the acoustic source. We use this setup to measure the node spacing (millimeters) and the acoustic trap force (picoNewtons). We anticipate that the simplicity of the experimental setup, the tractability of the theoretical equations, and the richness of the research topics on the subject will lead to an undergraduate laboratory with many interesting student projects.

1.
August
Kundt
, “
Ueber eine neue Art akustischer Staubfiguren und über die Anwendung derselben zur Bestimmung der Schallgeschwindigkeit in festen Körpern und Gasen
,”
Ann. Phys.
203
(
4
),
497
523
(
1866
).
2.
Mikael
Evander
and
Johan
Nilsson
, “
Acoustofluidics 20: Applications in acoustic trapping
,”
Lab Chip
12
(
22
),
4667
4676
(
2012
).
3.
Sz-Chin Steven
Lin
,
Xiaole
Mao
, and
Tony Jun
Huang
, “
Surface acoustic wave (SAW) acoustophoresis: Now and beyond
,”
Lab Chip
12
(
16
),
2766
2770
(
2012
).
4.
Adem
Ozcelik
,
Joseph
Rufo
,
Feng
Guo
,
Yuyang
Gu
,
Peng
Li
,
James
Lata
, and
Tony Jun
Huang
, “
Acoustic tweezers for the life sciences
,”
Nat. Methods
15
(
12
),
1021
1028
(
2018
).
5.
Karl
Olofsson
,
Björn
Hammarström
, and
Martin
Wiklund
, “
Ultrasonic based tissue modelling and engineering
,”
Micromachines
9
(
11
),
594
(
2018
).
6.
Andreas
Nilsson
,
Filip
Petersson
,
Henrik
Jönsson
, and
Thomas
Laurell
, “
Acoustic control of suspended particles in micro fluidic chips
,”
Lab Chip
4
(
2
),
131
135
(
2004
).
7.
Martin
Wiklund
,
Roy
Green
, and
Mathias
Ohlin
, “
Acoustofluidics 14: Applications of acoustic streaming in microfluidic devices
,”
Lab Chip
12
(
14
),
2438
2451
(
2012
).
8.
Peiran
Zhang
,
Hunter
Bachman
,
Adem
Ozcelik
, and
Tony Jun
Huang
, “
Acoustic microfluidics
,”
Annu. Rev. Anal. Chem.
13
(
1
),
17
43
(
2020
).
9.
Minji
Kim
,
Emma
Huff
,
Mathieu
Bottier
,
Susan
Dutcher
,
Philip
Bayly
, and
John
Meacham
, “
Acoustic trap-and-release for rapid assessment of cell motility
,”
Soft Matter
15
(
21
),
4266
4275
(
2019
).
10.
Johannes F.
Spengler
and
W.
Terence Coakley
, “
Ultrasonic trap to monitor morphology and stability of developing microparticle aggregates
,”
Langmuir
19
(
9
),
3635
3642
(
2003
).
11.
Jong Seob
Jeong
,
Jung Woo
Lee
,
Chang Yang
Lee
,
Shia Yen
Teh
,
Abraham
Lee
, and
K.
Kirk Shung
, “
Particle manipulation in a microfluidic channel using acoustic trap
,”
Biomed. Microdev.
13
(
4
),
779
788
(
2011
).
12.
B.
Hammarström
,
Thomas
Laurell
, and
Johan
Nilsson
, “
Acoustic trapping of bacteria and nanoparticles in disposable glass capillaries using seed particles
,” in
Proceedings of the Micro Total Analysis Systems Conferences
, Seattle, WA, 2011, pp.
1707
1709
.
13.
Johan
Nilsson
,
Mikael
Evander
,
Björn
Hammarström
, and
Thomas
Laurell
, “
Review of cell and particle trapping in microfluidic systems
,”
Anal. Chim. Acta
649
(
2
),
141
157
(
2009
).
14.
Michaël
Baudoin
,
Jean-Claude
Gerbedoen
,
Antoine
Riaud
,
Olivier
Bou Matar
,
Nikolay
Smagin
, and
Jean-Louis
Thomas
, “
Folding a focalized acoustical vortex on a flat holographic transducer: Miniaturized selective acoustical tweezers
,”
Sci. Adv.
5
(
4
),
eaav1967
(
2019
).
15.
Andreas
Lenshof
,
Mikael
Evander
,
Thomas
Laurell
, and
Johan
Nilsson
, “
Acoustofluidics 5: Building microfluidic acoustic resonators
,”
Lab Chip
12
(
4
),
684
695
(
2012
).
16.
Bruce C.
Denardo
,
Stanley G.
Freemyers
,
Michael P.
Schock
, and
Scott T.
Sundem
, “
Acoustic radiation force due to a diverging wave: Demonstration and theory
,”
Am. J. Phys.
82
(
2
),
95
101
(
2014
).
17.
Bartlomiej
Chojnacki
,
Adam
Pilch
,
Marcin
Zastawnik
, and
Aleksandra
Majchrzak
, “
Acoustic levitation-standing wave demonstration
,” in
Audio Engineering Society Convention 143
, New York,
2017
.
18.
Wolfgang
Rueckner
, see <https://www.youtube.com/watch?v=XpNbyfxxkWE&t=126s> for “
Ultrasonic Levitation
” (
2017
) (accessed on January 30, 2021).
19.
David P.
Jackson
and
Ming-Hua
Chang
, “
Acoustic levitation and the acoustic radiation force
,”
Am. J. Phys.
89
(
4
),
383
392
(
2021
).
20.
Mathias
Ohlin
,
Ida
Iranmanesh
,
Athanasia E.
Christakou
, and
Martin
Wiklund
, “
Temperature-controlled MPa-pressure ultrasonic cell manipulation in a microfluidic chip
,”
Lab Chip
15
(
16
),
3341
3349
(
2015
).
21.
Björn
Hammarström
,
Nils R.
Skov
,
Karl
Olofsson
,
Henrik
Bruus
, and
Martin
Wiklund
, “
Acoustic trapping based on surface displacement of resonance modes
,”
J. Acoust. Soc. Am.
149
(
3
),
1445
1453
(
2021
).
22.
Ashley R.
Carter
,
Yeonee
Seol
, and
Thomas T.
Perkins
, “
Precision surface-coupled optical-trapping assay with one-basepair resolution
,”
Biophys. J.
96
(
7
),
2926
2934
(
2009
).
23.
Stephen R.
Okoniewski
,
Ashley R.
Carter
, and
Thomas T.
Perkins
, “
A surface-coupled optical trap with 1-bp precision via active stabilization
,”
Methods Mol. Biol.
1486
,
77
107
(
2017
).
24.
S. M.
Hagsäter
,
A.
Lenshof
,
P.
Skafte-Pedersen
,
J. P.
Kutter
,
T.
Laurell
, and
H.
Bruus
, “
Acoustic resonances in straight micro channels: Beyond the 1D-approximation
,”
Lab Chip
8
(
7
),
1178
1184
(
2008
).
25.
M.
Antfolk
,
P. B.
Muller
,
P.
Augustsson
,
H.
Bruus
, and
T.
Laurell
, “
Focusing of sub-micrometer particles and bacteria enabled by two-dimensional acoustophoresis
,”
Lab Chip
14
(
15
),
2791
2799
(
2014
).
26.
Marco A.
Catipovic
,
Paul M.
Tyler
,
Josef G.
Trapani
, and
Ashley R.
Carter
, “
Improving the quantification of Brownian motion
,”
Am. J. Phys.
81
(
7
),
485
491
(
2013
).
27.
Feng
Guo
,
Zhangming
Mao
,
Yuchao
Chen
,
Zhiwei
Xie
,
James P.
Lata
,
Peng
Li
,
Liqiang
Ren
,
Jiayang
Liu
,
Jian
Yang
,
Ming
Dao
,
Subra
Suresh
, and
Tony Jun
Huang
, “
Three-dimensional manipulation of single cells using surface acoustic waves
,”
Proc. Natl. Acad. Sci. U. S. A.
113
(
6
),
1522
1527
(
2016
).
28.
Subhasish
Dey
,
Sk Zeeshan
Ali
, and
Ellora
Padhi
, “
Terminal fall velocity: The legacy of Stokes from the perspective of fluvial hydraulics
,”
Proc. R. Soc. A
475
(
2228
),
20190277
(
2019
).
29.
Henrik
Bruus
, “
Acoustofluidics 7: The acoustic radiation force on small particles
,”
Lab Chip
12
(
6
),
1014
1021
(
2012
).
30.
R.
Hiorns
,
Polymer Handbook
, 4th ed., edited by
J.
Brandup
,
E.
Immergut
, and
E.
Grulke
(
John Wiley and Sons
,
New York
,
1999
), p.
2250
.
31.
Ashley R.
Carter
, “
Case study on how to develop 3D labs with theoretical, experimental, and computational goals
,” in
Conference on Laboratory Instruction beyond the First Year of College
,
2018
.
32.
Alejandra
Velasquez
,
Isabel P.
Hardy
,
Victoria D.
Kuntz
,
Daniel
Oo
, and
Ashley R.
Carter
, “
Bridging the disconnect between the classroom and research laboratory using projects
,” in
Conference on Laboratory Instruction beyond the First Year of College
,
2023
.
33.
Joseph
Kozminski
,
Heather
Lewandowski
,
Nancy
Beverly
,
Steve
Lindaas
,
Duane
Deardorff
,
Ann
Reagan
,
Richard
Dietz
,
Randy
Tagg
,
M.
EblenZayas
,
J.
Williams
et al, see <http://www.aapt.org/resources/upload/labguidlinesdocument_ebendorsed_nov10.pdf> for “
AAPT recommendations for the undergraduate physics laboratory curriculum
” (
2014
).
34.
Chuanyu
Zhang
,
Xiaofeng
Guo
,
Laurent
Royon
, and
Philippe
Brunet
, “
Acoustic streaming generated by sharp edges: The coupled influences of liquid viscosity and acoustic frequency
,”
Micromachines
11
(
6
),
607
(
2020
).
AAPT members receive access to the American Journal of Physics and The Physics Teacher as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.