Coplanarity driven fluorescence turn-on sensor for chromium(III) and its application for bio-imaging

Article abstract of DOI:10.1039/c7pp00425g

New benzimidazole and benzothiazole derivatives (S1-S3) derived from thiophene-2,5-dicarboxaldehyde and 5,5′-bipyridyldicarboxaldehyde with NSN/SSS/NN binding sites were tested against various cations and anions. S3 showed selectivity toward copper(ii) io

Full text of DOI:10.1039/c7pp00425g

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Coplanarity driven fluorescence turn-on sensor for chromium(III)
and its application towards bio-imaging
a
a,
Received 00th January 20xx,
Accepted 00th January 20xx
G. Balamurugan and S. Velmathi *
Thiophene-2,5-dicarboxaldehyde and o-phenylenediamine (oPDA) derived benzimidazole and its thiazole analogue, 5,5’-
bipyridyldicarboxaldehyde and oPDA derived benzimidazole (S1-S3) with NSN/SSS/NN binding sites were tested against
various cations. S3 showed selectivity towards copper(II) ions with the color change of pale yellow from colourless under
aqueous medium among other cations under consideration. In case of S1 and S2, no colour change was observed whereas
S1 alone showed selective fluorescence turn on for Cr(III) ions among other cations. S1 showed sensitivity towards Cr(III)
with fluorescent change with bathochromic shift. The prominent fluorescence change was applied to live cell imaging of
HeLa cells by S1 with Cr(III) ions.
DOI: 10.1039/x0xx00000x
www.rsc.org/
receptors display a highly selective fluorescence response toward
3
+ 11
Introduction
the addition of Cr . Xiaofeng et al. reported new rhodamine
spirolactam derivative containing a thiodiacetamide moiety and
two rhodamine B fluorophores and it exhibited a highly sensitive
As the coplanarity of the two aromatic ring connected by C-C single
bond is one of the major characteristics of fluorescent nature of the
compound, designing the receptor with the binding sites to attain
the coplanarity on interacting with a selective species will definitely
lead to the fluorescent change. Benzimidazole and oxazole
derivatives from heteroaromatic aldehyde could be as-said system
with NSN/SSS /NN binding sites which could be easily accessible to
metal ions. As chromium is one of the most important heavy metal
elements, various industrial and agricultural usages built up the
3
+
and selective turn-on fluorescent response for Cr in the presence
of other cations in a methanol-HEPES buffer solution with
1
2
micromolar detection limit. Jie Mao et al. reported two
rhodamine-based chemosensors and their sensing behavior toward
metal ions was investigated by fluorescence spectroscopies. Under
1
00% aqueous medium, they showed selectivity towards Cr(III)
1
3
among other metal ions . Kursunlu et al. reported a Bodipy-based
chemosensor for the sensing of Cr(III) in EtOH–H O medium. The
receptor displayed defined changes in UV-vis and fluorescence
3
+
2
toxicity level of Cr as an environmental pollutant. Chromium(III)
ion is a key component of a balanced human and animal diet and its
insufficiency causes interruption to the lipids and glucose
3
+
spectroscopic studies for Cr ions compared to other cations under
1
4
1
3+
investigation . Mukherjee et al. investigated the sensing behaviour
metabolism in living organisms . Under higher level exposure, Cr is
able to conjugate with various amino acids and forms mutagenic
of sensor containing quinoline moiety towards chromium ions
1
5
2
selectively due to CHEF effect with low detection limit . Wu et al.
discussed the sensing studies of a set of receptors containing a
pyridine-carboxhydrazone tridentate coordination site towards
alkali and alkaline earth metals and most first-row transition metals
binary-DNA or ternary-DNA adducts those are carcinogenic as well .
3
+
So, it is very important to develop chemosensor to detect Cr ions
3
+
in biological and environmental samples. Cr can be detected using
several instrumentation techniques such as, stripping voltammetric
analysis, reversed phase-high performance liquid chromatography
coupled to different spectrometric detection methods and atomic
3
+
in aqueous media. One of the receptor exhibits selectivity for Cr
over other cations and displayed high quantum yield (F = 0.86) and
1
6
3
-5
fluorescence enhancement . Colorimetric chemosensors based on
absorption spectrophotometry . Expensive instrumentation and
time consumption for analyses make chemosensors as a significant
analytical tool that could be used to detect ionic species. In recent
3
+
dimethyl yellow dye for “naked eye” detection of Cr in aqueous
1
7
media via test papers are also reported . Also, relay recognition of
3
+
2+
3
+
Cr were reported by Gao et al. via in-situ receptor-Cu complex
years, fluorescent chemosensors for Cr have been reported based
3
+
6
-10
which could act as an efficient “off-on” fluorescence sensor for Cr
on various fluorophores
with the drawback of interference of
2
+
3+
ion with 1:1 replacement of Cu by Cr . This selective fluorescence
other trivalent metal ions like Fe(III) and Al(III) but they are less in
2
+
3+
“
on-off-on” sensor was used to identify Cu and Cr in live cell
numbers. Alejandra et al. demonstrated that phenanthroline based
1
8
imaging of MCF-7 cells . Compared to other transition metal ions,
chemosensor for chromium ions are reported in small number and
3
+
it is still advantageous to design a new probe for Cr with enhanced
sensitivity and selectivity under physiological condition. In most of
the chromium sensor reported papers, the interference of other
3
+
3+
trivalent ions like Fe and Al was unavoidable. Herein, we report
the photophysical properties and sensing studies of heteroaromatic
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systems (S1-S3) with NSN, SSS and NN binding sites. S1 showed CHNS analysis: Calculated - C, 61.68%; H, 2.88%; N, 7.99%; S,
3
+
selectivity towards Cr with fluorescence turn-on with no 27.45% and found C, 60.99%; H, 2.90%; N, 7.88%; S, 28.23%
2
+
interference of trivalent iron. S3 showed selectivity towards Cu
with color change to yellow from colourless and fluorescence Scheme 1 Syntheses of the receptors (S1-S3)
quenching. Furthermore, chemosensor S1 has been effectively
3
+
applied in the recognition of Cr in biological samples like HeLa
macrophage cells with authentic blue fluorescence.
Materials and Methods
All the compounds were purchased from Sigma Aldrich and Merck
Chemicals and used as such. Shimadzu UV-2600 UV-vis
spectrophotometer was used to record UV-visible spectra using
quartz cell with 1 cm path length. Fluorescence emission spectra
were recorded in a Shimadzu RF-5301 PC spectrofluorophotometer.
Excitation wavelength was set based on λmax of the respective
derivative. Horiba Jobin Yvon Fluoromax 4 with Flurohub A+ (TCSPC)
lifetime controller was used to demonstrate lifetime measurement
with nanoLED light source 340 nm with sub 100 ps lifetime
measurements. HRMS analysis was done using Bruker Daltonics Flex
5
7
d
,5'-bis(1H-benzo[d]imidazol-2-yl)-2,2'-bipyridine (S3)
1
5% yield; Orange solid; mp: 180-184°C; H NMR (500 MHz, DMSO-
6
): δ 13.24 (s, 2H, -NH), 9.51 (s, 2H), 8.71 (d, J=8 Hz, 2H), 8.66 (d,
1
3
-3
2H), 7.75 (d, 2H), 7.62 (d, 2H), 7.28 (m, 4H); C NMR (125 MHz,
DMSO-d6): 155.65, 149.07, 147.91, 135.39, 126.95, 121.44, 119.65,
Analysis with reflector acquisition mode. 1.5 x10 M stock solution
of the receptor in DMSO was prepared and used for sensing studies,
-1
-
5
112.07; FTIR (KBr, ν cm ): 3301 (N-H str.), 1622, 1600 (C=N str.),
1418 (C=C str.), 765, 751, 742 (ar. CH bending); ESI Mass Spectrum:
5
x10 M were prepared in respective solvent system by diluting
−3
−3
3
with CH CN, 1.5 × 10 M aq. solutions of the cations and 1.5 × 10
+
Calcd. for C24
H N
16 6
: m/z 388.1436 found: m/z 388.8850 (M ). CHNS
M of anions in DMSO were prepared. The cell Hela line was
provided by the Food Industry Research and Development Institute
analysis: Calculated - C, 74.21%; H, 4.15%; N, 21.64% and found C,
7.30%; H, 4.37%; N, 18.33%.
7
(
Taiwan). Hela cells were cultured in Dulbecco’s modified Eagle’s
medium (DMEM) supplemented with 10% fetal bovine serum (FBS)
at 37 °C under an atmosphere of 5% CO . Cells were plated on 18
Results and Discussion
2
mm glass coverslips and allowed to adhere for 24 h.
Synthesis of receptors and effect of solvents
General procedure for the synthesis of receptors (S1-S3)
Aldehyde (0.5 mmol) and o-substituted aniline (1.2 mmol/0.6
mmol) were taken in DMSO (0.5 mL) and heated to 120°C for 6 h.
Imidazole and oxazole derivatives were synthesized using
respective dicarboxaldehyde and o-substituted amine derivatives in
good yield and purity (Scheme 1). All the derivatives were
1
9, 20
(
Scheme 1)
The completion of the reaction was monitored by
1
13
characterized using H NMR, C NMR and HRMS. The photophysical
properties of receptors were established in various solvents with
UV−vis absorpꢀon and fluorescence emission studies. The stock
thin layer chromatography (TLC) using hexane: ethylacetate (6:4) as
an eluent. After cooling the reaction mixture to room temperature,
cold ethanol (5 mL) was added and stirred for few minutes. The
solid obtained was filtered, washed with ethanol (5 mL x 3 times),
dried and triturated with ethanol (5 mL) to yield pure receptors.
-3
solutions of receptors (1.5x10 M in DMSO) were prepared and
diluted with the solvent under consideration. Generally, acetonitrile
(
ACN) and rarely dimethylsulfoxide (DMSO) were used for the
analysis of sensing activities in the many reported works.
5% yield; Yellow solid; mp: 182-184°C; H NMR (500 MHz, DMSO- Even though there is no much difference among λmax of S2 in
): δ 13.11 (s, 2H), 7.89 (m, 2H), 7.57-7.65 (m, 4H), 7.24 (m, 4H); various solvents, the fluorescence intensities of S2 under different
2
8
d
,5-bis(1H-benzo[d]cimidazol-2-yl)thiophene (S1)
1
6
1
3
C NMR (125 MHz, DMSO-d
6
): 145.7, 138.0, 139.0, 129.9, 124.2, solvents revealed the key role of the polarity of the solvent via
15.2; FTIR (KBr, ν cm ): 3388 (N-H str.), 3068, 1561, 712 (C-H hydrogen bonding. In moderately polar solvents such as acetone,
S: m/z 316.0783. 1,4-dioxane and tetrahydrofuran, S2 showed good fluorescence
-1
1
12 4
bending); ESI Mass Spectrum: Calcd. for C18H N
Found: m/z 317.1000(M+1). CHNS analysis: Calculated - C, 68.33%; with red shift than other polar solvents those showed weak
H, 3.82%; N, 17.71%; S, 10.13% and found C, 70.53%; H, 3.65%; N, fluorescent (Fig. 1a-b).
1
6.81%; S, 9.01%.
Purposely, our motive is to investigate the sensing behaviour of S1-
S3 towards the cations in water therefore ACN will be the prime
choice due to its higher miscibility with water and good
2
8
d
2
1
1
,5-bis(benzo[d]thiozol-2-yl)thiophene (S2)
1
1% yield; Yellow solid; mp: 186-188°C; H NMR (500 MHz, DMSO- fluorescence property. From the effect of water towards the
): δ 8.07 (d, 2H), 7.88 (d, 2H), 7.68 (s, 2H), 7.51 (t, 2H), 7.40 (t, fluorescence emission of S3 under ACN medium, a gradual decrease
6
1
3
H); C NMR (125 MHz, DMSO-d
6
): 160.29, 153.79, 140.22, 135.00,
in the fluorescence with bathochromic shift was observed due to
-1
28.77, 126.69, 125.66, 123.35, 121.56; FTIR (KBr, ν cm ): 3050, the hydrogen bonding interaction between water molecule and
622, (C=N str.), 1434, 756 (C-H bending); HRMS Mass Spectrum: imidazole –NH of the same (Fig. 1c).
10 2 3
Calcd. for C18H N S m/z 350.4804 Found: m/z 351.9260 (M+1).
2
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Fig. 1 (a, b) UV-vis and PL spectroscopic studies of S2 in a range of solvent like ACN, THF, toluene, EtOH, DMF, DMSO and H
water towards the fluorescence spectra of S3.
2
O; (c) Effect of
Fig. 2 (a) UV-vis spectral studies of S1 (50ꢀM in H
2
O) with various cations (1.5 mM in H
2
O); (b) Incremental addition of chromium (III) ions
O).
(
0-2.0 eq.) to S1 (c) UV-vis spectral studies of S3 (3 mL of 50ꢀM in ACN) with various cations (1.5 mM in H
2
incremental addition (0-2.0 eq.) of Cr(III) to S1, a gradual shift of the
band at 370 to 380 nm was observed and shoulder peaks were
disappeared gradually(Fig. 2b). S2 does not show any change in UV-
vis studies whereas in case of S3, Cu(II) displayed selective
bathochromic shift from 354 to 384 nm corresponding to ligand to
metal charge transfer (LMCT) and other cations did not show any
authentic red shift of the receptor n-π* band (Fig. 2c).
Naked eye sensing
As-synthesized receptors were tested against various cations and
anions under ACN medium for the visual color change experiment.
2
00 ꢀL of cations (1.5 mM in H
50 ꢀM in ACN). Among the receptors, S3 showed selective naked
eye sensing of Cu(II) with color change from colourless to yellow
Fig. SI1a). In case of S1 and S2, no color change was observed
2
O) were added to 3 mL of receptor
(
(
under visible light whereas S1 interestingly displayed selective
fluorescence turn on for Cr(III) ions among other cations under UV
light (365 nm). S2 did not show any fluorescence change for any
cations. Although S3 showed selective change in color for copper(II)
ions, most of the cations showed fluorescence turn on or turn
offbehaviour without any selectivity under UV light which is not
encouraging for being a good sensor(Fig. SI1b). On addition of
anions with these receptors, neither color change nor fluorescence
change was observed.
UV-vis spectral studies
UV-vis spectral studies revealed that S1 showed absorption maxima
3
+
at 370 nm with two shoulder peaks at 353 and 390 nm. After Fig. 3 (a) Fluorescence turn on for Cr under UV light (365 nm); (b)
3
+
addition of chromium ions, the shoulder peaks were disappeared Fluorescence spectroscopic titration of incremental addition of Cr
and the absorption maximum was shifted bathochromically from (0-2.0 eq.) to S1; (c) Interference studies of other metal ions
3
+
3
70 to 380 nm (Fig. 2a). In UV-vis spectroscopic titration with the towards the sensing behaviour of Cr with S1.
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Table 1 Binding constant (Ka), detection limit (LOD) and quantum yield of host-guest interaction.
-
1
Entry
Host-Guest
Binding Constant (M )
LOD (M)
Quantum Yield φ
Stoichiometric
ratios(Host:Guest)
3
+
5
-8
1
2
S1-Cr
1.12 x 10
1.75 x 10
0.029358 (S1- 0.037205)
1:1
1:2
2
+
3
-8
S3-Cu
8.04 x 10
6.62x10
--
Fluorescence spectroscopic analysis
and 9, which coincides with the biologically applicable pH range
21
(
6.0–7.6).
Fluorescence spectroscopic analysis of the sensing behaviour of S1
towards cations was studied on exciting at 360 nm, a bathochromic
shift from 430 to 462 nm was observed for chromium(III). But in the
case of S3, complete quenching of the fluorescence emission band
at 500 nm was observed on exciting at 360 nm for copper ions and
Physical properties and stoichiometric ratio
Binding constants of the receptors with the selective species was
calculated using Benesi-Hildebrand plot by plotting 1/[Guest] (y
axis) against 1/(A
slope, binding constant can be calculated. Detection limit was
enhancement of S1-Cr was due to the inhibition of Intramolecular determined using standard deviation and slope of the calibration
o
-A) (x axis). By dividing intercept of the plot by
2
+
2+
Zn , Cd
etc. showed fluorescence turn on. Fluorescence
3
+
3
+
charge transfer. In case of S1-Cr , Cr(III) must be bound with NSN curve. Job’s plot studies were used to find the stoichiometry ratio of
tridentate of S1 resulting with the formation of co-planarity lead to the host-guest complexes. Determination of quantum yield (the
the inhibition of ICT followed by the fluorescence enhancement.
Quantitative analysis of cations sensed by the receptors could be
achieved due to the linearity in the fluorescent intensity observed
in the case of incremental addition of cation (0-2.0 eq.) of interest
characteristics of fluorescence turn on behavior) and the calculated
values were tabulated in table 1. S1 showed good binding constant
with subnanomolar detection limit and 1:1 stoichiometric ratio with
chromium ions. Red shift of the emission spectrum with the
reduction of intensity area led to the lesser quantum yield of S1-
(
Fig. 3a-b).
3
+
3+
Cr complex than that of S1 (Fig. 3b). HRMS analysis of S1-Cr
complex supported the 1:1 stoichiometric ratio of the complex (Fig.
Interference studies was demonstrated using fluorescence
spectroscopy with the addition of Cr(III) ions to the cations-receptor
mixture and found that no interference was observed for the 4). S3 showed lesser binding constant with subnanomolar detection
sensing of Cr(III) by S1. On addition of mercury ions, the limit and 1:2 stoichiometric ratio.
fluorescence of S1 was quenched due to heavy atom effect. Cr(III)
ions showed predominance over mercury(II) ions towards the
sensing. In case of S3, the interaction of Cu(II) ions with receptor S3
did not altered by any of the cations under consideration.
The fluorescence lifetime of the receptor S1 and its respective in-
3
+
situ Cr complex in ACN were determined using time dependent
photoluminescence decay process. A pinch of milk powder in water
was used for the instrument prompt. nanoLED source (340 nm) was
used to excite the receptor and using TCSPC fluorohub, life time of
3
+
S1 was found to be 1.26 ns whereas on addition of Cr ions,
Lifetime of the complex was delayed couple of nanoseconds (3.14
ns) (Fig. S2). The delay in the fluorescence response time could be
referred for the fluorescence turn on as the inhibition of the
intramolecular charge transfer occurred due to the coordination of
3
+
Cr ions.
3
+
The sensing behaviour of S1 towards Cr ions was tested under
various pH. 20 mM of 4-(2-hydroxyethyl)-1-piperazineethane
sulfonic acid (HEPES) in DMSO:H
2
O (9:1) at pH 7.4 was used as for
studies and pH was adjusted with 0.1 M aq. HCl and 0.1 M NaOH.
3
+
Fluorescence intensity changes at 430 nm for S1 on addition of Cr
3
+
ions under was not altered at low pH upon addition of Cr ions. At
3
+
pH 6.0-9.0, the addition of Cr ions to S1 showed the bathochromic
shift 430 nm to 462 nm. Under basic medium (pH 10-12), for S1
itself bathochromic shift from 430 nm to 462 nm was observed and
3
+
on addition of Cr ions, no change was observed (Fig. S3). This can
be attributed to the deprotonation of imidazole –NH at pH 9.0–11.0
3
+
and addition of Cr resulted in no change in the fluorescence
intensity. Thus, S1 displayed a significant response between pH 6
3
+
Fig. 4 HRMS analysis of the S1-Cr complex.
4
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Conclusions
We have studied the sensing behaviour of benzimidazole and
thiazole derivatives from heteroaromatic aldehyde (S1-S3) with
3
+
NSN/SSS /NN binding sites. S1 showed selectivity towards Cr with
fluorescence enhancement and showed good binding constant and
subnanomolar detection limit. Other receptors did not show any
useful selectivity towards the cations or anions. Most importantly,
3
+
Fig. 5. Sensing mechanism of S1 towards Cr ions.
3+
S1 has a better selectivity for Cr over other ions tested under the
same conditions, which meet the selective requirements for
Sensing Mechanism
2
+
practical application except Hg . S1 displayed a significant response
between pH 6 and 9, which coincides with the biologically
applicable pH range (6.0–7.6). Interestingly, living cell imaging
experiments of Hela cells by S1 further demonstrate its value in the
practical applications.
Since the coplanarity of the two aromatic ring connected by C-C
single bond is one of the major characteristics of fluorescent nature
of the compound, free –C-C- single rotation among thiophene and
benzimidazole ring of S1 was inhibited by the coordination of
chromium ions and the coplanarity of these two rings was achieved
2
0
followed by the strong fluorescence output . On excitation, the
3
+
intramolecular charge transfer in S1 was inhibited by Cr addition.
Conflicts of interest
There are no conflicts to declare.
Bio imaging of HeLa cells
Bio-imaging of HeLa cells was carried out with S1 and Cr(III). Acknowledgement
3
+
Experiments to assess the Cr ions uptake were performed in PBS Author GB thanks UGC (University Grant Commission, India) for the
with 30μM Cr(ClO ) . H O. Treated with the cells with 6μL of 10 mM financial support through NET-SRF Scheme (F.2-8/2011(SA-1) dated
4
3
2
metal ions (final concentration: 30 μM) dissolved in sterilized PBS 29/11/2013) and Ministry of Human Resource and Development
pH 7.4) and incubated for 30 min at 37℃. The treated cells were (MHRD), Govt. of India, for providing infrastructure and
(
washed with PBS (3×2 mL) to remove remaining metal ions. Culture instrumentation facilities.
media (2 mL) was added to the cell culture, which was treated with
a 10 mM solution of S1 (2μL; final concentration: 10 μM) dissolved
in DMSO. The samples were incubated at 37℃ for 30 min. The
culture media was removed, and the treated cells were washed
References
1
. A. M. Zayed and N. Terry, Plant Soil, 2003, 249, 139-156.
with PBS (3×2 mL) before observation. Confocal fluorescence 2. H. Arakawa, F. Wu, M. Costa, W. Rom and M.-S. Tang,
imaging of cells was performed with a Leica TCS SP5 X AOBS Carcinogenesis, 2006, 27, 639-645.
Confocal Fluorescence Microscope (Germany), and a 63x oil- 3. E. Jorge, M. Rocha, I. Fonseca and M. Neto, Talanta, 2010, 81,
immersion objective lens was used. The cells were excited with a 556-564.
4
. C. Capellos and B. H. Bielski, Kinetic systems: mathematical
white light laser at 380 nm, and emission was collected at 460±10
nm. From the images, it could be inferred that S1 has very excellent
permeability through the cell membrane and has very weak
fluorescent whereas after the addition of chromium ions, S1 sensed
the guest selectively with enhanced blue fluorescent (Fig. 6).
description of chemical kinetics in solution, 1972.
5
6
. M. C. Pannain and R. E. Santelli, Talanta, 1995, 42, 1609-1617.
. V. Bravo, S. Gil, A. M. Costero, M. N. Kneeteman, U. Llaosa, P. M.
Mancini, L. E. Ochando and M. Parra, Tetrahedron, 2012, 68, 4882-
4
7
9
8
2
9
4
1
2
1
887.
. J. Y. Jung, S. J. Han, J. Chun, C. Lee and J. Yoon, Dyes Pigm., 2012,
4, 423-426.
. D. Li, C.-Y. Li, H.-R. Qi, K.-Y. Tan and Y.-F. Li, Sens. Actuators, B,
016, 223, 705-712.
. M. Sarkar, S. Banthia and A. Samanta, Tetrahedron Lett., 2006,
7, 7575-7578.
0. S. Goswami, K. Aich, A. K. Das, A. Manna and S. Das, RSC Adv.,
013, 3, 2412-2416.
1. A. de los Rios, P. Mal, A. J. Meixner, D. Khoptyar and M.
Schmittel, Bull. Chem. Soc. Jpn., 2011, 84, 620-622.
2. X. Bao, Q. Cao, X. Nie, Y. Zhou, R. Ye, B. Zhou and J. Zhu, Sens.
Actuators, B, 2015, 221, 930-939.
1
1
2
1
5
1
3. J. Mao, L. Wang, W. Dou, X. Tang, Y. Yan and W. Liu, Org. Lett.,
007, 9, 4567-4570.
4. A. N. Kursunlu, E. Şahin and E. Güler, RSC Adv., 2015, 5, 5951-
957.
Fig. 6 Fluorescence images of macrophage HeLa cells treated with
5. M. Mukherjee, B. Sen, S. Pal, M. S. Hundal, S. K. Mandal, A. R.
3
+
S1 and Cr . (Left) Bright field image; (Middle) fluorescence image;
Khuda-Bukhsh and P. Chattopadhyay, RSC Adv., 2013, 3, 19978-
9984.
and (Right) merged image.
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Photochemical & Photobiological Sciences
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DOI: 10.1039/C7PP00425G
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6. H. Wu, P. Zhou, J. Wang, L. Zhao and C. Duan, New J. Chem.,
009, 33, 653-658.
7. D.-H. Wang, Y. Zhang, R. Sun and D.-Z. Zhao, RSC Adv., 2016, 6,
640-4646.
8. Y. Gao, J. Shu, C. Zhang, X. Zhang, H. Chen and K. Yao, RSC Adv.,
015, 5, 74629-74637.
9. G. Balamurugan and S. Velmathi, Anal. Methods, 2016, 8, 1705-
710.
0. G. Balamurugan, P. Venkatesan, S. P. Wu and S. Velmathi, RSC
Adv., 2016, 6, 24229-24235.
1. N. Na, F. Wang, J. Huang, C. Niu, C. Yang, Z. Shang, F. Han and J.
Ouyang, RSC Adv., 2014, 4, 35459-35462.
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