Photonic crystal fiber based evanescent-wave sensor for detection of biomolecules in aqueous solutions

TL;DR: It is demonstrated that highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber even at wavelengths in the visible range is demonstrated.

Abstract: We demonstrate highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber. The air-suspended silica structures located between three neighboring air holes in the cladding crystal guide light with a large fraction of the optical field penetrating into the sample even at wavelengths in the visible range. An effective interaction length of several centimeters is obtained when a sample volume of less than 1 µL is used.

Summary

1. Introduction

• Since the advent of silica based Photonic Crystal Fibers (PCF) several unique properties have been demonstrated and utilized.
• The penetration of the optical field into the air-filled holes can be quite signdicant 141, and the fraction of the light propagating in the holes is even hgher when the holes are filled with a liquid.
• The small volumes required to fill tens of centimeters of fiber thus makes a PCF-device an interesting new solution when ultra small sample volumes are available.
• Cy5-DNA abso&s strongly around 650mq tllereby making detection possible by monitoring the transmission spectrum of white light propagating through the fiber.
• The transmitted power was measured with an Ando optical spectmm analyzer (AQ-63 15A) at a resolution of lnm.

3. Results and discussion

• Transmission spectra were measured for a PCF filled with an aqueous solution of Cy5 and a reference fiber filled with pure water.
• From the transmission spectra the absorption spectmm was derived.
• A comparison between the absorption spectra of the Cy5 solution and the reference is seen in Fig 3 Given the size of the PCF it is evident that the volume of the liquid is below O.SpL, which is a very small volume in senior applications.
• Still the absorption spectrum clearly shows that the device is capable of detecting the presence of Cy5 in the solution.

Full text

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Photonic crystal fiber based evanescent-wave sensor for detection of biomolecules in
aqueous solutions
Jensen, Jesper Bevensee; Pedersen, L H; Carlsen, A; Hoiby, P E; Nielsen, L B; Bjarklev, Anders
Overgaard; Hansen, T B
Published in:
Conference on Lasers and Electro-Optics, 2003. CLEO '03.
Link to article, DOI:
10.1109/CLEO.2003.1298075
Publication date:
2003
Document Version
Publisher's PDF, also known as Version of record
Link back to DTU Orbit
Citation (APA):
Jensen, J. B., Pedersen, L. H., Carlsen, A., Hoiby, P. E., Nielsen, L. B., Bjarklev, A. O., & Hansen, T. B. (2003).
Photonic crystal fiber based evanescent-wave sensor for detection of biomolecules in aqueous solutions. In
Conference on Lasers and Electro-Optics, 2003. CLEO '03. IEEE. https://doi.org/10.1109/CLEO.2003.1298075

CTuP5
Photonic crystal fiber based evanescent-wave sensor
for
detection
of
biomolecules in aqueous solutions
J.B. Jensen"), L.H. Pedersed'),
A.
Carlsen('),
P.E.
Roiby@',
L.B. Nielsen"',
A.
Bjarklev'", and T.P. Hansen""
"'Research Center COM, Technical University
of
Denmark, Building 345v, DK-2800 Kgs. Lyngby, Denmark
(2'Biotechnological Institute, Kogle
Alle
2,
DK-2970 Horsholm, Denmark
0,
Crystal
Fibre
NS,
Blokken 84, DK-3460 Birkerod, Denmark
J.B. Jensen
e-mail:
jbj@com.dtu.dk
Abstract:
We demonstrate evanescent-wave sensing of Cy5-DNA-molecules in an aqueous
solution using
a
photonic crystal fiber. Less than
0.8pL
sample volume placed
in
the holes of the
fiber is sufficient for reliable detection.
02002
Optical
Society
of
America
OCIS
codes:
(000.0000)
General
1.
Introduction
Since the advent
of
silica based Photonic Crystal Fibers (PCF) several unique properties have been demonstrated
and utilized. Endlessly single-mode guidance
[
11,
and
a
high degree of freedom in the design of the dispersion
propelties of the fiber
[2],
are
some of the properties, which make PCF's an interesting alternative to standard optical
fibers. Recently an interest in using the holey
structure
of the PCF for sensing purposes
has
arisen
[3].
The
penetration of the optical field into the air-filled holes can be quite signdicant 141, and the fraction of the light
propagating in the holes is even hgher when the holes
are
filled with a liquid. The overlap between the optical field
and the liquid is still lower than in conventional spectroscopy, but the long intemction length obtained when using
a
PCF based device compensates
this.
The small volumes required
to
fill tens of centimeters
of
fiber
thus
makes a
PCF-device
an
interesting new solution when ultra small sample volumes
are
available. We have used a PCF with
a
large air-filling factor (Fig.
1)
for evanescent-wave sensing of an aqueous solution of Cy5-DNA molecules.
Fig.
1
Cross section
of
the photonic crystal fiber used
Ibr
the evanescent wave sensor.
The
diameter
of
the microstructured
part
of
the fiber is 79~~
2.
Experimental
Using capillaq forces 17cm of the fiber was filled with a
25pM
solution
of
Cy5-DNA. The molecule is higlily
fluorescent and the filling of the fiber was monitored by epiflourescence microscopy (Fig
2).
Light propagating in
the liquid filled fiber
is
primarily guided in the silica structures throughout the microstructured cladding. The
smallness of these structures forces a large percentage of the light to penetrate into the liquid, thus providing a
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CTuP5
Fig.
2.
A
picture
of
the fluorescence from the
PCF
filled with
a
25
pM
95-DNA
solution.
strong interaction between the
light
and the molecules in the liquid. This makes the hollow-core
PCF
used in
this
study superior
to
those microstructured fibers, where a large majority of the guided light is propagating in
a
solid
silica core.
Cy5-DNA
abso&s
strongly around
650mq
tllereby making detection possible
by
monitoring the
transmission spectrum of white light propagating through the fiber. Whte light
was
launched into the fiber using a
microscope objective. The transmitted power was measured with an Ando optical spectmm analyzer
(AQ-63
15A) at
a resolution
of
lnm.
3.
Results and discussion
Transmission spectra were measured for a PCF filled with an aqueous solution of
Cy5
and a reference fiber filled
with pure water. From the transmission spectra
the
absorption spectmm was derived. A comparison between the
absorption spectra
of
the
Cy5
solution and the reference is seen in
Fig
3
I I
'
5kO
'
600
650
7
Wavelength
(nm)
Fig.
3.
The measured absorption spectrum
of
the
Cy5
solution compared with the reference fiber. The insert shows a
measurement
of
the
Cy5
absorption spectrum using a conventiond spectrometer.
Given the size
of
the
PCF
it is evident that the volume
of
the liquid is below O.SpL, which
is
a very
small
volume in
senior applications. Still the absorption spectrum clearly shows that the device
is
capable
of
detecting the presence
of
Cy5
in
the solution.
4.Conclusion
We have demonstrated the use of
a
photonic crystal fiber
as
an evanescent-wave sensor for the detection
of
biomolecules
in
an aqueous solution. Based on our measurements we conclude that the fiber used in our work is
lughly
suitable for sensing the presence
of
a given molecule
in
a
vay small sample volume.
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CTuP5
5.
References
I.T.A. Birks,
J.C. Knight, and P.St.J.Russell, "Endlessly single-mode photonic
crystal
fiber," Opt. Lett.
22,
961-963 (1997).
2.A.
Ferrando,
E.
Slivestre,
P.
Andres,
J.J.
Miret, and M.V. Andres, "Designing the properties
of
dispersion -flattened photonic crystal fibers,"
3.Y.L.
Hoo,
W.
Jin,
H.L.
Ho,
D.N.
Wang,
and R.S. Windeler, "Evanescent-wave
gas
sensing using microstructure fiber," Opt. Eng.
41
(l),
8-9
4.T.M.
Monro,
D.J. Richardson, and P.J. Bennett, "Developing holey fibres
for
evanescent filed devices," Electron. Lett.
35
(14), (1999)
Opt. Express
9
(13),
(2001).
(2002).
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