Type I collagen is the primary fibrillar component of the extracellular matrix, and functional properties of collagen arise from variations in fiber structure. This study investigated the ability of ultrasound to control collagen microstructure during hydrogel fabrication. Under appropriate conditions, ultrasound exposure of type I collagen during polymerization altered fiber microstructure. Scanning electron microscopy and second-harmonic generation microscopy revealed decreased collagen fiber diameters in response to ultrasound compared to sham-exposed samples. Results of mechanistic investigations were consistent with a thermal mechanism for the effects of ultrasound on collagen fiber structure. To control collagen microstructure site-specifically, a high frequency, 8.3-MHz, ultrasound beam was directed within the center of a large collagen sample producing dense networks of short, thin collagen fibrils within the central core of the gel and longer, thicker fibers outside the beam area. Fibroblasts seeded onto these gels migrated rapidly into small, circularly arranged aggregates only within the beam area, and clustered fibroblasts remodeled the central, ultrasound-exposed collagen fibrils into dense sheets. These investigations demonstrate the capability of ultrasound to spatially pattern various collagen microstructures within an engineered tissue noninvasively, thus enhancing the level of complexity of extracellular matrix microenvironments and cellular functions achievable within three-dimensional engineered tissues.

1.
Atala
,
A.
(
2009
). “
Engineering organs
,”
Curr. Opin. Biotechnol.
20
,
575
592
.
2.
Baker
,
B. M.
,
Nathan
,
A. S.
,
Gee
,
A. O.
, and
Mauck
,
R. L.
(
2010
). “
The influence of an aligned nanofibrous topography on human mesenchymal stem cell fibrochondrogenesis
,”
Biomaterials
31
,
6190
6200
.
3.
Braaten
,
J. V.
,
Goss
,
R. A.
, and
Francis
,
C. W.
(
1997
). “
Ultrasound reversibly disaggregates fibrin fibers
,”
Thromb. Haemostasis
78
,
1063
1068
.
4.
Butler
,
D. L.
,
Goldstein
,
S. A.
, and
Guilak
,
F.
(
2000
). “
Functional tissue engineering: The role of biomechanics
,”
J. Biomech. Eng.
122
,
570
575
.
5.
Carey
,
S. P.
,
Kraning-Rush
,
C. M.
,
Williams
,
R. M.
, and
Reinhart-King
,
C. A.
(
2012
). “
Biophysical control of invasive tumor cell behavior by extracellular matrix microarchitecture
,”
Biomaterials
33
,
4157
4165
.
6.
Cen
,
L.
,
Liu
,
W.
,
Cui
,
L.
,
Zhang
,
W.
, and
Cao
,
Y.
(
2008
). “
Collagen tissue engineering: Development of novel biomaterials and applications
,”
Pediatr. Res.
63
,
492
496
.
7.
Frantz
,
C.
,
Stewart
,
K. M.
, and
Weaver
,
V. M.
(
2010
). “
The extracellular matrix at a glance
,”
J. Cell. Sci.
123
,
4195
4200
.
8.
Garvin
,
K. A.
,
Dalecki
,
D.
, and
Hocking
,
D. C.
(
2011
). “
Vascularization of three-dimensional collagen hydrogels using ultrasound standing wave fields
,”
Ultrasound Med. Biol.
37
,
1853
1864
.
9.
Garvin
,
K. A.
,
Hocking
,
D. C.
, and
Dalecki
,
D.
(
2010
). “
Controlling the spatial organization of cells and extracellular matrix proteins in engineered tissues using ultrasound standing wave fields
,”
Ultrasound Med. Biol.
36
,
1919
1932
.
10.
Gelse
,
K.
,
Poschl
,
E.
, and
Aigner
,
T.
(
2003
). “
Collagens–structure, function, and biosynthesis
,”
Adv. Drug Delivery Rev.
55
,
1531
1546
.
11.
Gillette
,
B. M.
,
Rossen
,
N. S.
,
Das
,
N.
,
Leong
,
D.
,
Wang
,
M.
,
Dugar
,
A.
, and
Sia
,
S. K.
(
2011
). “
Engineering extracellular matrix structure in 3D multiphase tissues
,”
Biomaterials
32
,
8067
8076
.
12.
Grinnell
,
F.
, and
Petroll
,
W. M.
(
2009
). “
Cell motility and mechanics in three-dimensional collagen matrices
,”
Annu. Rev. Cell Dev. Biol.
26
,
335
361
.
13.
Hadjipanayi
,
E.
,
Mudera
,
V.
, and
Brown
,
R. A.
(
2009
). “
Guiding cell migration in 3D: A collagen matrix with graded directional stiffness
,”
Cell Motil. Cytoskeleton
66
,
121
128
.
14.
Hansen
,
L. K.
,
Wilhelm
,
J.
, and
Fassett
,
J. T.
(
2006
). “
Regulation of hepatocyte cell cycle progression and differentiation by type I collagen structure
,”
Curr. Top. Dev. Biol.
72
,
205
236
.
15.
Isenberg
,
B. C.
, and
Tranquillo
,
R. T.
(
2003
). “
Long-term cyclic distention enhances the mechanical properties of collagen-based media-equivalents
,”
Ann. Biomed. Eng.
31
(
8
),
937
949
.
16.
Kadler
,
K. E.
,
Baldock
,
C.
,
Bella
,
J.
, and
Boot-Handford
,
R. P.
(
2007
). “
Collagens at a glance
,”
J. Cell. Sci.
120
,
1955
1958
.
17.
Lee
,
C. H.
,
Singla
,
A.
, and
Lee
,
Y.
(
2001
). “
Biomedical applications of collagen
,”
Int. J. Pharmacol.
221
,
1
22
.
18.
McDaniel
,
D. P.
,
Shaw
,
G. A.
,
Elliott
,
J. T.
,
Bhadriraju
,
K.
,
Meuse
,
C.
,
Chung
,
K. H.
, and
Plant
,
A. L.
(
2007
). “
The stiffness of collagen fibrils influences vascular smooth muscle cell phenotype
,”
Biophys. J.
92
,
1759
1769
.
19.
McPherson
,
J. M.
,
Wallace
,
D. G.
,
Sawamura
,
S. J.
,
Conti
,
A.
,
Condell
,
R. A.
,
Wade
,
S.
, and
Piez
,
K. A.
(
1985
). “
Collagen fibrillogenesis in vitro: A characterization of fibril quality as a function of assembly conditions
,”
Coll. Relat. Res.
5
,
119
135
.
20.
Miron-Mendoza
,
M.
,
Seemann
,
J.
, and
Grinnell
,
F.
(
2010
). “
The differential regulation of cell motile activity through matrix stiffness and porosity in three dimensional collagen matrices
,”
Biomaterials
31
,
6425
6435
.
21.
Nasseri
,
B. A.
,
Ogawa
,
K.
, and
Vacanti
,
J. P.
(
2001
). “
Tissue engineering: An evolving 21st-century science to provide biologic replacement for reconstruction and transplantation
,”
Surgery
130
,
781
784
.
22.
Raub
,
C. B.
,
Suresh
,
V.
,
Krasieva
,
T.
,
Lyubovitsky
,
J.
,
Mih
,
J. D.
,
Putnam
,
A. J.
,
Tromberg
,
B. J.
, and
George
,
S. C.
(
2007
). “
Noninvasive assessment of collagen gel microstructure and mechanics using multiphoton microscopy
,”
Biophys. J.
92
,
2212
2222
.
23.
Roeder
,
B. A.
,
Kokini
,
K.
,
Sturgis
,
J. E.
,
Robinson
,
J. P.
, and
Voytik-Harbin
,
S. L.
(
2002
). “
Tensile mechanical properties of three-dimensional type I collagen extracellular matrices with varied microstructure
,”
J. Biomech. Eng.
124
,
214
222
.
24.
Rozario
,
T.
, and
DeSimone
,
D. W.
(
2009
). “
The extracellular matrix in development and morphogenesis: A dynamic view
,”
Dev. Biol.
341
,
126
140
.
25.
Sander
,
E. A.
, and
Barocas
,
V. H.
(
2008
). “
Biomimetic collagen tissues: Collagenous tissue engineering and other applications
” in
Collagen Structure and Mechanics
, edited by
P.
Fratzl
(
Springer
,
New York
), pp.
475
504
.
26.
Shoulders
,
M. D.
, and
Raines
,
R. T.
(
2009
). “
Collagen structure and stability
,”
Annu. Rev. Biochem.
78
,
929
958
.
27.
Stock
,
U. A.
, and
Vacanti
,
J. P.
(
2001
). “
Tissue engineering: Current state and prospects
,”
Annu. Rev. Med.
52
,
443
451
.
28.
Sung
,
K. E.
,
Su
,
G.
,
Pehlke
,
C.
,
Trier
,
S. M.
,
Eliceiri
,
K. W.
,
Keely
,
P. J.
,
Friedl
,
A.
, and
Beebe
,
D. J.
(
2009
). “
Control of 3-dimensional collagen matrix polymerization for reproducible human mammary fibroblast cell culture in microfluidic devices
,”
Biomaterials
30
,
4833
4841
.
29.
Wood
,
G. C.
(
1960
). “
The formation of fibrils from collagen solutions. II. A mechanism of collagen-fibril formation
,”
Biochem. J.
75
,
598
605
.
30.
Yang
,
Y. L.
,
Leone
,
L. M.
, and
Kaufman
,
L. J.
(
2009
). “
Elastic moduli of collagen gels can be predicted from two-dimensional confocal microscopy
,”
Biophys. J.
97
,
2051
2060
.
31.
Yang
,
Y. L.
,
Motte
,
S.
, and
Kaufman
,
L. J.
(
2010
). “
Pore size variable type I collagen gels and their interaction with glioma cells
,”
Biomaterials
31
,
5678
5688
.
32.
Zaman
,
M. H.
,
Trapani
,
L. M.
,
Sieminski
,
A. L.
,
Mackellar
,
D.
,
Gong
,
H.
,
Kamm
,
R. D.
,
Wells
,
A.
,
Lauffenburger
,
D. A.
, and
Matsudaira
,
P.
(
2006
). “
Migration of tumor cells in 3D matrices is governed by matrix stiffness along with cell-matrix adhesion and proteolysis
,”
Proc. Natl. Acad. Sci. U. S. A.
103
,
10889
10894
.
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