Page 1
Supporting Information of
Dicoumarol assisted synthesis of water dispersible gold nanoparticles for colorimetric sensing of
cysteine and lysozyme in biofluids
Betha Saineelima B. Kasibabu, Jigna R. Bhamore, Stephanie L. D’souza and Suresh Kumar
Kailasa*
Department of Applied Chemistry, S. V. National Institute of Technology, Surat-395 007, India*Corresponding author, Phone: +91-261-2201730; Fax: +91-261-2227334
E-mail: [email protected] ; [email protected]
O
O
O
O
O
O
O
OOH
O
OOH
O
O
OO
O
O
O O
HO
O
OHO
HAuCl4 +
DIC
DIC-Au NPs
Analytes
(Cys or lysozyme)
Electrostatic interaction
Hydrogen bonding and
π-π interactions
Aggregation of DIC-Au NPs induced by Cys or Lys
+
+
+
++
+
+
+
+
+
Scheme S1. A schematic representation of the mechanism for the colorimetric sensing Cys and Lys
using DIC-Au NPs as a probe.
Electronic Supplementary Material (ESI) for RSC Advances.This journal is © The Royal Society of Chemistry 2015
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Figure S1. UV-visible spectra of DIC-Au NPs at different concentrations of DIC (18.8 – 48.8 mM).
Inset: Photographic image of corresponding solutions.
400 500 600 700 800 900
0.0
0.3
0.6
0.9
1.2
1.5
18.8 mM
28.8 mM
38.8 mM
48.8 mM
Concentration of DIC (mM)
Ab
sorb
an
ce (
a.u
.)
Wavelength (nm)
1.5
400 500 600 700 800 900 1000
0.0
0.3
0.6
0.9
1.2
1.5
0°°°°C
25 °°°°C
50 °°°°C
75 °°°°C
100 °°°°C
Temperature (oC)
Figure S2. UV-visible spectra of DIC-Au NPs at different temperature ( 0 – 100oC). Inset:
Photographic image of DIC-Au NPs at different temperature.
Ab
sorb
an
ce (
a.u
.)
Wavelength (nm)
Page 3
(a)
Tra
nsm
itta
nce
(%
)
C=O
C-H, aromatic (3087)
C-H aliphatic (2933)
C=C, aromatic
(1600, 1557)
-OH group stretching
(b)
Tra
nsm
itta
nce
(%
)
Wavenumber (cm-1)
C=O lactone
-OH group stretching was disappeared
Figure S3. FT-IR spectra of (a) pure DIC and (b) DIC-Au NPs.
Page 4
(a)
2.0
AuNPs
2 pH
400 500 600 700 800 900 1000
0.0
0.3
0.6
0.9
1.2
1.5
1.8
2.1
2.4
2.7
AuNPs
2 pH
3 pH
4 pH
5 pH
6 pH
7 pH
8 pH
9 pH
10 pH
11 pH
12 pH
(b)
Ab
sorb
an
ce (
a.u
.)
Wavelength (nm)
Figure S4. (a) UV-visible spectra of DIC-Au NPs in the presence of Cys (1 mM) at ammonium
acetate pHs from 2.0 to 12.0. Inset: Photographic image of corresponding solutions. (b) UV-
visible spectra of DIC-Au NPs in the presence of Cys (1 mM) at PBS pHs from 2.0 to 12.0.
Inset: Photographic image of corresponding solutions.
400 500 600 700 800 900 1000
0.0
0.5
1.0
1.5
2.0 2 pH
3 pH
4 pH
5 pH
6 pH
7 pH
8 pH
9 pH
10 pH
11 pH
12 pH
Ab
sorb
an
ce (
a.u
.)
Wavelength (nm)
Page 5
400 500 600 700 800 900
0.00
0.25
0.50
0.75
1.00
DIC-Au NPs
pH 2
pH 3
pH 4
pH 5
pH 6
pH 7
pH 8
pH 9
pH 10
pH 11
pH 12
(b)
(a)
Ab
sorb
an
ce (
a.u
.)
Wavelength (nm)
Figure S5. (a) UV-visible spectra of DIC-Au NPs in the presence of Cys (1 mM) at Tris-HCl
pHs from 2.0- to 12.0. (b) Photographic image of corresponding solutions.
(b)
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(b)
400 500 600 700 800 900 1000
0.3
0.6
0.9
1.2
1.5
1.8
2.1 AuNPs
2 pH
4 pH
6 pH
8 pH
10 pH
12 pH
(a)
1.2 AuNPs
2 pH
3 pH
Ab
sorb
an
ce (
a.u
.)
Wavelength (nm)
Figure S6. (a) UV-visible spectra of DIC-Au NPs in the presence of Lys (50 µM) at ammonium
acetate pHs from 2.0 to 12.0. Inset: Photographic image of corresponding solutions. (b) UV-
visible spectra of DIC-Au NPs in the presence of Lys 50 µM) at PBS pHs from 2.0 to 12.0. (c)
Photographic image of corresponding solutions.
400 500 600 700 800 900 1000
0.2
0.4
0.6
0.8
1.0
3 pH
4 pH
5 pH
6 pH
7 pH
8 pH
9 pH
10 pH
11 pH
12 pH
Ab
sorb
an
ce (
a.u
.)
Wavelength (nm)
Page 7
Figure S7. UV-visible spectra of DIC-Au NPs in the presence of Lys (50 µM) at Tris-HCl pH
400 500 600 700 800 900 1000
0.0
0.3
0.6
0.9
1.2
1.5
AuNPs
2 pH
4 pH
6 pH
8 pH
10 pH
12 pH
Ab
sorb
an
ce (
a.u
.)
Wavelength (nm)
Figure S7. UV-visible spectra of DIC-Au NPs in the presence of Lys (50 µM) at Tris-HCl pH
from 2.0 to 12.0. Inset: Photographic image of corresponding solutions.
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1.2
AuNPs
2 pH(b)
400 500 600 700 800 900 1000
0.0
0.5
1.0
1.5
2.0
2.5
AuNPs
2 pH
4 pH
6 pH
8 pH
10 pH
12 pH
Ab
sorb
an
ce (
a.u
.)
Wavelength (nm)
(a)
400 500 600 700 800 900 1000
0.0
0.3
0.6
0.9
2 pH
4 pH
6 pH
8 pH
10 pH
12 pH
Figure S8. (a) UV-visible spectra of DIC-Au NPs in the presence of ammonium acetate buffer in pH range
from 2.0 to 12.0 without anlytes. Inset: Photograph of corresponding solutions. (b) UV-visible spectra of
DIC-Au NPs in the presence of PBS in pH range from 2.0 to 12.0. Inset: Photograph of corresponding
solutions.
(b)
Ab
sorb
an
ce (
a.u
.)
Wavelength (nm)
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0.0
0.5
1.0
1.5 AuNPs
2 pH
4 pH
6 pH
8 pH
10 pH
12 pH
Ab
sorb
an
ce (
a.u
.)
Figure S9. UV-visible spectra of DIC-Au NPs in the presence of Tris-HCl buffer in pH range from 2.0 to
12.0 without anlytes. Inset: Photograph of corresponding solutions.
400 500 600 700 800 900 1000
0.0
Wavelength (nm)
Page 10
0.0
0.3
0.6
0.9
1.2
1.5
AuNPs
0.05 M
0.1 M
0.2 M
0.3 M
0.4 M
0.5 M
0.6 M
0.7 M
0.8 M
0.9 M
1.0 M
Concentration of NaCl (0.05-1.0 M)
Ab
sorb
an
ce (
a.u
.)
400 500 600 700 800 900 1000 1100
0.0
Wavelength (nm)
Figure S10. UV-visible spectra of DIC-Au NPs by the addition of NaCl from 0.05 to 1.0 M
without target analytes. Inset images are the corresponding photographs of Au NPs color.
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A666/A
525
y = 0.013x - 0.015
R² = 0.994
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 20 40 60 80 100
LOD 2.2 µM
Figure S11. Calibration graph for the detection of Cys in the concentration range of 10-90 µM
using DIC-Au NPs as a probe at absorption ratio at A666/A525 versus Cys concentration.
Concentration (µM)
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A570/A
525
y = 0.441x + 0.485
R² = 0.996
0.4
0.5
0.6
0.7
0.8
0.9
0 0.2 0.4 0.6 0.8 1
LOD 8.7 nM
Figure S12. Calibration graph for the detection of Lys in the concentration range of 100-800 nM
using DIC-Au NPs as a probe at absorption ratio at A570/A525 versus Lys concentration.
Concentration (µM)
0 0.2 0.4 0.6 0.8 1
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0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
DIC-Au NPs
DIC-Au NPs+Mixture of A.A
DIC-Au NPs+Mixture of A.A+Cysteine
DIC-Au NPs+Mixture of A.A+Lysozyme
DIC-Au NPs+Cysteine
DIC-Au NPs+Lysozyme
Ab
sorb
an
ce (
a.u
.)
Figure S13. UV-visible absorbance spectra of DIC-Au NPs in the presence of various
aminoacids (phenyl alanine, histidine, 4-hydroxyproline, proline, trypophan, tyrosine, alanine,
isoleucine, aspargine, aspartic acid, methonine, lysine, serine and leucine, 1 mM) for detection
of Cys and Lys. Inset: the corresponding photographic image.
400 500 600 700 800 900
0.0
Wavelength (nm)
Page 14
400 500 600 700 800 900 1000
0.0
0.3
0.6
0.9
1.2
1.5
Ab
sorb
an
ce (
a.u
.)
Wavelength (n.m)
AuNPs
AuNPs+ Mixture of metal ions
AuNPs+ Mixture of metal ions+ Cys
AuNPs+ Mixture of metal ions+ Lys
Figure S14. UV-visible absorbance spectra of DIC-Au NPs in the presence of Cys and Lys upon addition
of various metal ions (Na+, K+, Br2+, Ca2+,Cu2+, Zn2+, Ni2+, Fe2+, Fe3+ and Al3+, 1.0 mM). Inset: the
corresponding photographic image.
Wavelength (nm)
400 500 600 700 800 900 1000
0.0
0.3
0.6
0.9
1.2
1.5
Abso
rbance (
a.u
.)
Wavelength (n.m)
AuNPs
AuNPs+ Mixture of anions
AuNPs+ Mixture of anions+Cys
AuNPs+ Mixture of anions+ Lys
Figure S15. UV-visible absorbance spectra of DIC-Au NPs in the presence of Cys and Lys upon addition
of various anions (Cl-, Br-, I- , F- , SO42- ,S2- , PO4
3- and Cr2O72- , 1.0 mM). Inset: the corresponding
photographic image.
Wavelength (nm)
Page 15
0.3
0.6
0.9
1.2
1.5
Ab
sorb
an
ce
(a
.u.)
AuNPs
AuNPs+ Mixture of pesticides
AuNPs+ Mixture of pesticides+ Cys
AuNPs+ Mixture of pesticides+ Lys
400 500 600 700 800 900 1000
0.0
Figure S16. UV-visible absorbance spectra of DIC-Au NPs in the presence of Cys and Lys upon
addition of various pesticides (chlorpyrifos, quinalphos, hexaconazole, tricyclazole, acephate,
metsulfuron, isoproturon, and chlopropham, 1.0 mM). Inset: the corresponding photographic image.
Wavelength (nm)
Page 16
0.3
0.6
0.9
1.2
1.5
Ab
sorb
an
ce (
a.u
.)
AuNPs
Egg without spiking
Egg spiking with 0.2 µM
Standard solution of 0.2 µM
Ab
sorb
an
ce (
a.u
.)
400 500 600 700 800 900 1000
0.0
0.3
Wavelength (n.m)Wavelength (nm)
Figure S17. UV-visible spectral variations of DIC-Au NPs in egg white (without spiking of
Lys), and with spiking 0.2 µM of Lys and the spectrum of DIC-Au NPs in the presence of
standard Lys at PBS pH 7.
Page 17
Sample Cys Lys
Addeda
FoundaRecovery
(%)b
RSD Addeda
FoundaRecovery
(%)b
RSD
Urine 1 40 39.8 99.5 0.28 0.2 0.21 104.8 2.2
60 59.9 99.8 0.18 0.5 0.52 104.0 2.9
80 78.0 97.5 1.82 0.8 0.81 102.2 2.2
Urine 2 40 39.1 97.8 0.12 0.2 0.19 98.6 2.7
60 57.6 96.0 0.38 0.5 0.51 101.0 2.1
80 77.8 97.3 0.98 0.8 0.81 100.8 1.6
Urine 3 40 41.2 103.2 0.23 0.2 0.20 101.3 0.7
60 63.7 106.2 0.18 0.5 0.49 99.4 1.1
80 85.2 106.5 0.42 0.8 0.81 101.3 1.3
Plasma 1 40 42.2 105.7 0.45 0.2 0.19 97.2 0.3
60 65.0 108.3 0.14 0.5 0.47 95.1 1.8
80 85.8 107.2 1.79 0.8 0.75 94.3 1.8
Plasma 2 40 0.2
Table S1. Analysis of Cys and Lys in biological samples using DIC-Au NPs as a probe.
Plasma 2 40 39.1 97.8 0.10 0.2 0.19 95.3 2.6
60 58.9 98.3 0.11 0.5 0.49 98.9 1.3
80 78.1 97.6 1.80 0.8 0.77 96.0 1.8
Plasma 3 40 39.1 97.7 0.44 0.2 0.21 102.0 0.9
60 57.5 95.9 0.14 0.5 0.50 100.2 1.5
80 77.3 96.6 0.93 0.8 0.79 99.15 2.3
Egg white - - - - 0.2 0.22 108.4 2.5
- - - - 0.5 0.55 110.6 2.0
- - - - 0.8 0.86 108.5 2.6
aµM, bn=3