Liquids in 10–100 nm spaces are expected to play an important role in biological systems. However, the liquid properties and their influence on biological activity have been obscured due to the difficulty in nanoscale measurements, either in vivo or in vitro. In this study, an in vitro analytical platform for biological systems is established. The nanochannels were modified with lipid bilayers, thereby serving as a model for biological confinement, e.g., the intercellular or intracellular space. As a representative property, the proton diffusion coefficient was measured by a nanofluidic circuit using fluorescein as a pH probe. It was verified that proton conduction was enhanced for channel widths less than 330 nm. A proton-related enzymatic reaction, the hydrolysis reaction, was also investigated, and a large confinement effect was observed.

1.
J.-X.
Cheng
,
S.
Pautot
,
D. A.
Weitz
, and
X. S.
Xie
,
Proc. Natl. Acad. Sci. U.S.A.
100
,
9826
9830
(
2003
).
2.
E. G.
Finer
and
A.
Darke
,
Chem. Phys. Lipids
12
,
1
16
(
1974
).
3.
J.
Fitter
,
R. E.
Lechner
, and
N. A.
Dencher
,
J. Phys. Chem. B
103
,
8036
8050
(
1999
).
4.
M. C.
Wiener
,
G. I.
King
, and
S. H.
White
,
Biophys. J.
60
,
568
576
(
1991
).
5.
S.
König
,
E.
Sackmann
,
D.
Richter
,
R.
Zorn
,
C.
Carlile
, and
T. M.
Bayerl
,
J. Chem. Phys.
100
,
3307
3316
(
1994
).
6.
X.
Chen
,
W.
Hua
,
Z.
Huang
, and
H. C.
Allen
,
J. Am. Chem. Soc.
132
,
11336
11342
(
2010
).
7.
N.
Amdursky
,
Y.
Lin
,
N.
Aho
, and
G.
Groenhof
,
Proc. Natl. Acad. Sci. U.S.A.
116
,
2443
2451
(
2019
).
8.
S.
Serowy
,
S. M.
Saparov
,
Y. N.
Antonenko
,
W.
Kozlovsky
,
V.
Hagen
, and
P.
Pohl
,
Biophys. J.
84
,
1031
1037
(
2003
).
9.
A.
Springer
,
V.
Hagen
,
D. A.
Cherepanov
,
Y. N.
Antonenko
, and
P.
Pohl
,
Proc. Natl. Acad. Sci. U.S.A.
108
,
14461
14466
(
2011
).
10.
W.
Zhao
,
D. E.
Moilanen
,
E. E.
Fenn
, and
M. D.
Fayer
, “Water at the surfaces of aligned phospholipid multibilayer model membranes probed with ultrafast vibrational spectroscopy,”
J. Am Chem. Soc.
130
(42),
13927
13937
(
2008
).
11.
P.
Ball
,
Chem. Rev.
108
,
74
108
(
2008
).
12.
A. S.
Lyon
,
W. B.
Peeples
, and
M. K.
Rosen
,
Nat. Rev. Mol. Cell Biol.
22
,
215
235
(
2021
).
13.
S.
Leroy
,
A.
Steinberger
,
C.
Cottin-Bizonne
,
A.-M.
Trunfio-Sfarghiu
, and
E.
Charlaix
,
Soft Matter
5
,
4997
–5002 (
2009
).
14.
Y.
Zhou
and
T.
Shimizu
,
Chem. Mater.
20
,
625
633
(
2008
).
15.
K.
Mawatari
,
Y.
Kazoe
,
H.
Shimizu
,
Y.
Pihosh
, and
T.
Kitamori
,
Anal. Chem.
86
,
4068
4077
(
2014
).
16.
H.
Chinen
,
K.
Mawatari
,
Y.
Pihosh
,
K.
Morikawa
,
Y.
Kazoe
,
T.
Tsukahara
, and
T.
Kitamori
,
Angew. Chem. Int. Ed.
51
,
3573
3577
(
2012
).
17.
T.
Tsukahara
,
A.
Hibara
,
Y.
Ikeda
, and
T.
Kitamori
,
Angew. Chem. Ed.
46
,
1180
1183
(
2007
).
18.
T.
Tsukahara
,
W.
Mizutani
,
K.
Mawatari
, and
T.
Kitamori
,
J. Phys. Chem. B
113
,
10808
10816
(
2009
).
19.
K.
Mawatari
,
K.
Isogai
,
K.
Morikawa
,
H.
Ushiyama
, and
T.
Kitamori
,
J. Phys. Chem. B
125
,
3178
3183
(
2021
).
20.
M.
Wang
,
Y.
Hou
,
L.
Yu
, and
X.
Hou
,
Nano Lett.
20
,
6937
6946
(
2020
).
21.
Y.
Hou
and
X.
Hou
,
Science
373
,
628
629
(
2021
).
22.
P. J.
Scales
,
F.
Grieser
,
T. W.
Healy
,
L. R.
White
, and
D. Y. C.
Chan
,
Langmuir
8
,
965
974
(
1992
).
23.
L.
Li
,
Y.
Kazoe
,
K.
Mawatari
,
Y.
Sugii
, and
T.
Kitamori
,
J. Phys. Chem. Lett.
3
(17), 2447–2452 (
2012
).
24.
H.
Emon
,
K.
Mawatari
,
T.
Tsukahara
, and
T.
Kitamori
, in
Proceedings of Micro Total Analysis System
(Chemical and Biological Microsystems Society,
2009
), p.
1524
–1526.
25.
P. S.
Cremer
and
S. G.
Boxer
,
J. Phys. Chem. B
103
,
2554
2559
(
1999
).
26.
T. J.
Mcintosh
and
S. A.
Simon
,
Annu. Rev. Biophys. Biomol. Struct.
23
,
27
51
(
1994
).
27.
R.
Ohta
,
K.
Mawatari
,
T.
Takeuchi
,
K.
Morikawa
, and
T.
Kitamori
,
Biomicrofluidics
13
,
024104
(
2019
).
28.
Y.
Kazoe
,
K.
Mawatari
,
L.
Li
,
H.
Emon
,
N.
Miyawaki
,
H.
Chinen
,
K.
Morikawa
,
A.
Yoshizaki
,
P. S.
Dittrich
, and
T.
Kitamori
,
J. Phys. Chem. Lett.
11
,
5756
5762
(
2020
).
29.
T.
Tsukahara
,
K.
Mawatari
,
A.
Hibara
, and
T.
Kitamori
,
Anal. Bioanal. Chem.
391
,
2745
2752
(
2008
).
30.
K.
Ikeda
,
Y.
Kazoe
,
T.
Tsukahara
,
K.
Mawatari
, and
T.
Kitamori
, in
Proceedings of Micro Total Analysis System
(Chemical and Biological Microsystems Society,
2014
), p.
61
–63.
31.
N.
Kučerka
,
Y.
Liu
,
N.
Chu
,
H. I.
Petrache
,
S.
Tristram-Nagle
, and
J. F.
Nagle
,
Biophys. J.
88
,
2626
2637
(
2005
).
32.
K.
Morikawa
,
K.
Mawatari
,
Y.
Kazoe
,
T.
Tsukahara
, and
T.
Kitamori
,
Appl. Phys. Lett.
99
,
123115
(
2011
).
33.
K.
Mawatari
,
H.
Koreeda
,
K.
Ohara
,
S.
Kohara
,
K.
Yoshida
,
T.
Yamaguchi
, and
T.
Kitamori
,
Lab Chip
18
,
1259
1264
(
2018
).
34.
J.
Shirai
,
K.
Yoshida
,
H.
Koreeda
,
T.
Kitamori
,
T.
Yamaguchi
, and
K.
Mawatari
,
J. Mol. Liq.
350
,
118567
(
2022
).
You do not currently have access to this content.