Primary cancers disseminate both single circulating tumor cells (CTCs) and CTC “clusters,” the latter of which have been shown to demonstrate greater metastatic propensity and adverse impact on prognosis. Many devices developed to isolate single CTCs also capture CTC clusters, but there is translational potential for a platform specifically designed to isolate CTC clusters. Herein, we introduce our microfluidic device for isolating CTC clusters (“Microfluidic Isolation of CTC Clusters” or MICC), which is equipped with ∼10 000 trap chambers that isolate tumor cell clusters based on their large sizes and dynamic force balance against a pillar obstacle in the trap chamber. Whole blood is injected, followed by a wash step to remove blood cells and a final backflush to release intact clusters for downstream analysis. Using clusters from tumor cell-line and confocal microscopy, we verified the ability of the MICC platform to specifically capture tumor cell clusters in the trap chambers. Our flow rate optimization experiments identified 25 μl/min for blood injection, 100 μl/min as wash flow rate, and 300 μl/min as the release flow rate – indicating that 1 ml of whole blood can be processed in less than an hour. Under these optimal flow conditions, we assessed the MICC platform’s capture and release performance using blood samples spiked with different concentrations of clusters, revealing a capture efficiency of 66%–87% and release efficiency of 76%–90%. The results from our study suggest that the MICC platform has the potential to isolate CTC clusters from cancer patient blood, enabling it for clinical applications in cancer management.

1.
J. D.
O’Flaherty
 et al, “
Circulating tumour cells, their role in metastasis and their clinical utility in lung cancer
,”
Lung Cancer
76
,
19
25
(
2012
).
2.
V.
Plaks
,
C. D.
Koopman
, and
Z.
Werb
, “
Cancer. Circulating tumor cells
,”
Science
341
,
1186
1188
(
2013
).
3.
N.
Aceto
,
M.
Toner
,
S.
Maheswaran
, and
D. A.
Haber
, “
En route to metastasis: Circulating tumor cell clusters and epithelial-to-mesenchymal transition
,”
Trends Cancer
1
,
44
52
(
2015
).
4.
N.
Aceto
 et al, “
Circulating tumor cell clusters are oligoclonal precursors of breast cancer metastasis
,”
Cell
158
,
1110
1122
(
2014
).
5.
I. J.
Fidler
, “
The relationship of embolic homogeneity, number, size and viability to the incidence of experimental metastasis
,”
Eur. J. Cancer
9
,
223
227
(
1973
).
6.
D. G.
Duda
 et al, “
Malignant cells facilitate lung metastasis by bringing their own soil
,”
Proc. Natl. Acad. Sci. U.S.A.
107
,
21677
21682
(
2010
).
7.
A.
Fabisiewicz
and
E.
Grzybowska
, “
CTC clusters in cancer progression and metastasis
,”
Med. Oncol.
34
,
12
(
2017
).
8.
C.
Paoletti
 et al, “
Significance of circulating tumor cells in metastatic triple-negative breast cancer patients within a randomized, phase II trial: TBCRC 019
,”
Clin. Cancer Res.
21
,
2771
2779
(
2015
).
9.
I.
Cima
 et al, “
Tumor-derived circulating endothelial cell clusters in colorectal cancer
,”
Sci. Transl. Med.
8
,
345ra389
(
2016
).
10.
B.
Molnar
,
A.
Ladanyi
,
L.
Tanko
,
L.
Sreter
, and
Z.
Tulassay
, “
Circulating tumor cell clusters in the peripheral blood of colorectal cancer patients
,”
Clin. Cancer Res.
7
,
4080
4085
(
2001
).
11.
J. M.
Hou
 et al, “
Clinical significance and molecular characteristics of circulating tumor cells and circulating tumor microemboli in patients with small-cell lung cancer
,”
J. Clin. Oncol.
30
,
525
532
(
2012
).
12.
S. L.
Stott
 et al, “
Isolation of circulating tumor cells using a microvortex-generating herringbone-chip
,”
Proc. Natl. Acad. Sci. U.S.A.
107
,
18392
18397
(
2010
).
13.
W.
Sheng
 et al, “
Capture, release and culture of circulating tumor cells from pancreatic cancer patients using an enhanced mixing chip
,”
Lab Chip
14
,
89
98
(
2014
).
14.
S.
Nagrath
 et al, “
Isolation of rare circulating tumour cells in cancer patients by microchip technology
,”
Nature
450
,
1235
1239
(
2007
).
15.
A. F.
Sarioglu
 et al, “
A microfluidic device for label-free, physical capture of circulating tumor cell clusters
,”
Nat. Methods
12
,
685
691
(
2015
).
16.
Y. T.
Kang
,
I.
Doh
,
J.
Byun
,
H. J.
Chang
, and
Y. H.
Cho
, “
Label-free rapid viable enrichment of circulating tumor cell by photosensitive polymer-based microfilter device
,”
Theranostics
7
,
3179
3191
(
2017
).
17.
D. L.
Adams
 et al, “
The systematic study of circulating tumor cell isolation using lithographic microfilters
,”
RSC Adv.
9
,
4334
4342
(
2014
).
18.
S. H.
Au
 et al, “
Clusters of circulating tumor cells traverse capillary-sized vessels
,”
Proc. Natl. Acad. Sci. U.S.A.
113
,
4947
4952
(
2016
).
19.
N.
Kamyabi
,
Z. S.
Khan
, and
S. A.
Vanapalli
, “
Flow-induced transport of tumor cells in a microfluidic capillary network: Role of friction and repeated deformation
,”
Cell. Mol. Bioeng.
10
,
563
576
(
2017
).
20.
N.
Kamyabi
and
S. A.
Vanapalli
, “
Microfluidic cell fragmentation for mechanical phenotyping of cancer cells
,”
Biomicrofluidics
10
,
021102
(
2016
).
21.
Y.
Xia
and
G. M.
Whitesides
, “
Soft lithography
,”
Annu. Rev. Mater. Sci.
28
,
153
184
(
1998
).
22.
A.
Bollinger
,
P.
Butti
,
J. P.
Barras
,
H.
Trachsler
, and
W.
Siegenthaler
, “
Red blood cell velocity in nailfold capillaries of man measured by a television microscopy technique
,”
Microvasc. Res.
7
,
61
72
(
1974
).
23.
F. A.
Coumans
,
G.
van Dalum
,
M.
Beck
, and
L. W.
Terstappen
, “
Filtration parameters influencing circulating tumor cell enrichment from whole blood
,”
PLoS One
8
,
e61774
(
2013
).
24.
G.
Vona
 et al, “
Isolation by size of epithelial tumor cells: A new method for the immunomorphological and molecular characterization of circulating tumor cells
,”
Am. J. Pathol.
156
,
57
63
(
2000
).
25.
A. C.
Guyton
and
J. E.
Hall
,
Textbook of Medical Physiology
, 11th ed. (
Elsevier Saunders
,
2006
), pp.
161
194
.
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