A colorimetric and fluorometric oligothiophene-indenedione-based sensor for rapid and highly sensitive detection of cyanide in real samples and bioimaging in living cells

Article abstract of DOI:10.1016/j.dyepig.2018.12.057

A new simple oligothiophene-indenedione-based sensor 3TI has been synthesized for the highly reactive and selective detection of cyanide anion (CN^?) in 70% aqueous media. The sensor 3TI displays distinct colorimetric and fluorometric detection of CN^? due to the addition of CN^? to the electron-deficient indenedione-vinyl group of 3TI, which hampers intramolecular charge transfer (ICT) efficiencies. The recognition mechanism of 3TI for CN^? was confirmed by the optical measurements, ¹H NMR titration, FTIR spectra, HRMS analysis, and TD-DFT calculations. The sensor 3TI for CN^? shows the outstanding advantages of high fluorescence brightness, fast response time (30 s), low detection limit (31.3 nM), minimal pH dependence in the physiologically relevant range, and excellent selectivity in presence of other competitive anions. Encouraged by these desirable sensing properties, the 3TI has been successfully used for determination of CN^? in real water and food samples, silica-based sensing kits and fluorescence imaging in living cells with satisfactory results.

Full text of DOI:10.1016/j.dyepig.2018.12.057

Dyes and Pigments 163 (2019) 667–674
Contents lists available at ScienceDirect
Dyes and Pigments
journal homepage: www.elsevier.com/locate/dyepig
A colorimetric and fluorometric oligothiophene-indenedione-based sensor
for rapid and highly sensitive detection of cyanide in real samples and
bioimaging in living cells
Zongrang Guo, Tingting Hu, Tao Sun, Tianduo Li , Hong Chi, Qingfen Niu∗∗
∗
Shandong Provincial Key Laboratory of Molecular Engineering, School of Chemistry and Pharmaceutical Engineering, Qilu University of Technology (Shandong Academy of
Sciences), Jinan, 250353, People's Republic of China
A R T I C L E I N F O
A B S T R A C T
Keywords:
A new simple oligothiophene-indenedione-based sensor 3TI has been synthesized for the highly reactive and
−
Oligothiophene-indenedione
Colorimetric sensor
Fluorometric sensor
Cyanide
Real sample
Live-cell imaging
selective detection of cyanide anion (CN ) in 70% aqueous media. The sensor 3TI displays distinct colorimetric
−
−
and fluorometric detection of CN due to the addition of CN to the electron-deficient indenedione-vinyl group
of 3TI, which hampers intramolecular charge transfer (ICT) efficiencies. The recognition mechanism of 3TI for
−
1
CN was confirmed by the optical measurements, H NMR titration, FTIR spectra, HRMS analysis, and TD-DFT
−
calculations. The sensor 3TI for CN shows the outstanding advantages of high fluorescence brightness, fast
response time (30 s), low detection limit (31.3 nM), minimal pH dependence in the physiologically relevant
range, and excellent selectivity in presence of other competitive anions. Encouraged by these desirable sensing
−
properties, the 3TI has been successfully used for determination of CN in real water and food samples, silica-
based sensing kits and fluorescence imaging in living cells with satisfactory results.
−
1. Introduction
efficient method for detecting CN in aqueous as well as in cellular
environments. Traditional detection methods (such as potentiometry
−
Cyanide (CN ) is well-known for its extreme toxicity to mammals
and conventional titration) are expensive, laborious, time consuming,
and require complicated instrumentation and skillful operators, which
greatly limited their wide applications. Therefore, these limitations
leave distinct scope for the development of a safe, simple, selective and
because of its ability to bind to the active site of cytochrome oxidase
and inhibit cellular respiration [1]. CN poisoning can result in vo-
−
miting, convulsions, unconsciousness, and eventual death. Never-
theless, cyanide as an important chemical reagent is extensively used in
diverse areas such as electroplating, metal mining, plastic manufacture
and X-ray film recovery, and can easily reach the environment [2]. In
addition, in nature cyanide generally occurs in many food and plants,
such as cassava, bamboo shoots, sorghum, green potatoes, sprouting
potatoes, and bitter seeds [3]. As a result, the widespread application of
−
sensitive molecular sensor for CN detection and quantification in
environmental and biological systems.
A number of excellent sensors have been developed in recent years
−
[8,9], however, colorimetric and fluorometric sensors for CN anions
have received considerable attention due to their outstanding features
such as their user-friendly nature suitable for on-site analysis, simpli-
city, high sensitivity and selectivity, visual detection, and potential for
in vivo imaging [10–14]. Simultaneously, colorimetric sensing, which
−
CN anions raises a large number of environmental concerns, parti-
cularly in terms of its retention in leech circuits, recovery, and potential
for contamination [4]. Only 0.5–3.5 mg of cyanide per kilogram of body
weight can lead to death in humans [5,6]. The World Health Organi-
−
allows convenient monitoring of target CN anions by the naked eye
without resorting to any expensive instrumentation, has appealed great
−
−
zation (WHO) allows the maximum acceptable level of CN in drinking
attention in recent years [15–17]. The design of CN -selective fluor-
−
water less than 1.9 μM [7]. Despite safeguards and stringent norms set
by different regulatory bodies, the any accidental release of cyanide to
the environment can contaminate drinking water and cause serious
problems. All the above factors extremely need the development of an
escent sensors generally relies on the nucleophilic attack of CN on the
electrophilic functional group such as dicyanovinyl [18–23], aldehyde
[24–27], indolium [28–31], barbituric acid [32] and trifluoromethyl
group [33], resulting in changes in π-conjugated system and thus the
∗
Corresponding author.
∗∗
Corresponding author.
E-mail addresses: litianduo@163.com (T. Li), qf_niu1216@qlu.edu.cn (Q. Niu).
https://doi.org/10.1016/j.dyepig.2018.12.057
Received 7 November 2018; Received in revised form 10 December 2018; Accepted 25 December 2018
Available online 28 December 2018
0143-7208/ © 2018 Elsevier Ltd. All rights reserved.

Z. Guo et al.
Dyes and Pigments 163 (2019) 667–674
special fluorescent properties. This exhibits high sensitivity and ex-
cellent selectivity for CN detection. However, some of them also show
indenedione-vinyl), 1621, 1594 and 1573 (C=C, aromatic ring).
−
several drawbacks such as narrow pH working range, lack of sensing
ability in aqueous solution, inability to perform cellular imaging, lack
of colorimetric change and creation of turn-off instead of turn-on
fluorescent sensor. Therefore, developing a new colorimetric and turn-
on fluorescent sensor for CN detection with favorable working pH
span, high sensitivity and cell-penetrating ability would be highly de-
sirable.
2
.3. Theoretical calculation
All theoretical calculations were carried out by using the Gaussian
0
3
9 program package [35]. Geometries of the sensor 3TI and its complex
−
–
TI-CN were optimized by using density functional theory (DFT) cal-
culations at the B3LYP/6-31G* level of theory [36,37], and then, the
time-dependent density functional theory (TD-DFT) method was used
to obtain the transition energy and absorption spectra. The binding
pattern of 3TI with CN were further proposed from the calculation
results using DFT/TD-DFT method.
In view of this requirement and as part of our research effort de-
voted to ion recognition, herein, we have designed and synthesized a
−
new simple oligothiophene-indenedione-based colorimetric and turn-on
−
2
fluorescent sensor for the naked-eye detection of CN in THF/H O (3:7,
v/v) solution based on the mechanism of intramolecular charge transfer
ICT) inhibiting. What's more, this sensor features a lot of benefits, such
2.4. Cytotoxicity assay
(
as colorimetric and turn-on fluorescence dual-mode response, high se-
lectivity and sensitivity, fast response time, favorable working pH
range, and applicability in physiological conditions. The sensor could
detect cyanide in real water and food samples as well as the silica based
sensing kits. In addition, the novel sensor is well biocompatible, which
is an added advantage for living cells applications.
The cytotoxicity of sensor 3TI to HeLa cells was studied through a
MTT assay. HeLa cells were seeded into 96-well microplates at a density
5
of 1 × 10 cells/mL in 100 μL medium containing 10% FCS (Fetal Calf
Serum) and incubated for 24 h. The cells were cultured in different
concentrations (0–30 μM) of sensor 3TI solutions in incubator (37 °C,
5
2
% CO and 95% air) for 24 h. After that, 10 μL MTT (5 mg/mL) was
added to each well and continue incubated for another 4 h. Then, these
2. Experimental section
−1
cells were dissolved in DMSO (150 μL well ), and the absorbance level
was analyzed at 492 nm by microplate reader (Multiskan™ FC
Microplate Photometer, Thermo Scientific, USA). The treated wells re-
lative to that in the control and the culture medium was used as a
control.
2.1. Materials and instrumentations
All chemical reagents and solvents used were obtained commer-
cially at analytical grade and used without further purification.
Deionized water was used throughout the experiment.
Tetrabutylammonium salt of anions (CN , F , Cl , AcO , NO
−
−
−
−
−
3
,
2
.5. Cell culture and fluorescence imaging
−
2−
−
−
−
3
−
4
2−
SCN , CO
3
, HCO
3
, HS , HSO
, HSO
and SO
4
) were pur-
chased from Sigma-Aldrich and stored in vacuum desiccators. The
The living HeLa cells that were cultured in DMEM (Dulbecco's
−
3
various anions above were diluted to 1.0 × 10 M by deionized water
to obtain the stock solutions. The deionized water obtained from the
Millipore Milli-Q system with 18 MΩ was used throughout all of the
Modified Eagle's Medium) supplemented with 10% FBS (fetal bovine
serum) at 37 °C under an atmosphere of 5% CO were chosen for the
cell imaging experiments. First, the living HeLa cells and sensor 3TI
2
2
experiments. All the analytical solutions were prepared in THF/H O
(
10 μM) were cultured in cell culture medium for 1 h at 37 °C, washed
(
3:7, v/v) solution. Compounds 3T and 3T-CHO were prepared ac-
with PBS buffer (pH = 7.4) for three times, and then imaging. Then,
cyanide ion (25 μM) was added to the pre-cultured cells of the sensor
cording to the well-known literature procedure [34].
NMR spectra were recorded on Bruker AvanceⅡ NMR spectrometer
3
TI, cultured for 30 min at 37 °C, washed with PBS buffer (pH = 7.4)
1
13
at an operating frequency of 400 MHz for H NMR and 100 MHz for
C
for three times, then imaging. After 60 min, imaging the cells that
loaded cyanide ion again were observed under CLSM. The fluorescence
for 3TI images were taken by excitation at 488 nm and the emission was
collected from 500 to 550 nm.
–
NMR in DMSO-d
6
. Infrared spectra of 3TI and 3TI-CN were recorded
on Bruker ALPHA FT-IR spectrometer using KBr pellets. High-resolution
mass spectra (HRMS) were recorded on Agilent 6510 Accurate-Mass Q-
TOF LC/MS system. The UV–Vis absorption and emission spectra were
measured using a Shimadzu UV-2600 and Hitachi F-4600 fluorescence
spectrophotometer, respectively. The fluorescence images were col-
lected by a Leica TCS SP8 confocal-laser scanning microscope (CLSM)
with an objective oil lens of 63X magnification. All pH measurements
were performed with a PHS-3C meter.
3
. Results and discussion
3
.1. Preparation of 3TI
The sensor 3TI was successfully synthesized by a straightforward
condensation reaction of compound 3T-CHO with 1,3-indenedione in
EtOH as the solvent to give the product in 89% yield as depicted in
Scheme 1. The resultant product 3TI was fully characterized by using
standard spectroscopic techniques such as H NMR, C NMR, FTIR and
HRMS spectra (Figs. S1–S4).
2
.2. Synthesis of sensor 3TI
Compound 3T-CHO (100 mg, 0.36 mmol) and 1,3-indendione
1
13
(
52.9 mg, 0.36 mmol) were dissolved in dry EtOH (50 mL). The mixture
was stirred under reflux overnight. Then the mixture was cooled to
room temperature, and the formed precipitate was filtered off, washed
with ethanol and dried in vacuum to obtain pure compound 3TI
(
130.3 mg, yield 89%)as a deep red solid. 1H NMR: (400 MHz, DMSO-
d
7
7
6
, ppm): δ = 8.22 (d, J = 4.0 Hz, 1H), 8.07 (s, 1H), 7.93–7.97 (m, 4H),
.65–7.68 (m, 2H), 7.64 (d, J = 8.0 Hz, 1H), 7.49 (d, J = 4.0 Hz, 1H),
1
3
.44 (d, J = 4.0 Hz, 1H), 7.16 (t, J = 4.0 Hz, 1H); C NMR: (100 MHz,
, ppm): δ = 189.28, 189.10, 148.37, 145.48, 141.33, 139.90,
38.70, 135.56, 135.52, 135.44, 135.41, 135.28, 133.98, 128.63,
28.22, 126.70, 125.60, 125.49, 125.24, 123.32, 122.70, 122.56;
DMSO-d
1
1
6
+
HRMS (ESI): m/z [M+H] calcd for: C22
H
13
O
2
3
S : 405.0078, found:
−
1
Scheme 1. The synthetic route of sensor 3TI.
405.0071; FTIR: (KBr, cm ) ν = 1721 (C=O), 1676 (C=C, 1,3-
668

Z. Guo et al.
Dyes and Pigments 163 (2019) 667–674
Fig. 2. (a) Changes in the emission spectra of 3TI (1.0 μM) upon addition of
Fig. 1. (a) The UV–vis absorption spectra of sensor 3TI (1.0 μM) towards 10.0
different analytes (10.0 equiv.) in THF/H O (3:7, v/v) solution; (b)
2
equiv. various analytes in THF/H
2
O (3:7, v/v) solution; (b) Visual solution
Fluorescence color changes upon different analytes added to sensor 3TI under
color change in 3TI in the presence of various analytes in the sun light. (For
interpretation of the references to color in this figure legend, the reader is re-
ferred to the Web version of this article.)
365 nm UV lamp. (For interpretation of the references to color in this figure
legend, the reader is referred to the Web version of this article.)
3.3. Anti-interference capacity
−
3.2. The optical response of sensor 3TI toward CN
−
Excellent anti-interference capacity is a key factor for a good CN
The sensing abilities of 3TI were investigated by UV–Vis spectro-
fluorescent sensor. Thus, to validate anti-interference capability of
scopy and fluorescence spectroscopy in THF/H
The UV–vis spectra of the 3TI (1.0 μM) shows a low energy band at
12 nm and a high energy band at 349 nm due to intramolecular charge
2
O (3:7, v/v) solution.
sensor 3TI, competitive experiments were performed in the presence of
−
1
0 equiv. of CN and 10 equiv. of various other tested analytes
5
aforementioned by fluorescence spectroscopy (Fig. 3). These tested
transfer (ICT) from oligothiophene moiety to electron deficient 1,3-in-
denedione moiety and π-π* transition, respectively. When different
−
analytes except for CN gave no visible change and were not found to
induce any significant interference even at higher concentrations. These
findings confirmed the excellent selectivity and excellent anti-inter-
−
−
−
−
−
kinds of analytes (10 equiv.) such as CN , F , Cl , AcO , NO
3
,
−
2−
−
−
2−
−
−
3
SCN , CO
Cys) were respectively added to the solution of 3TI (1.0 μM), only CN
was found to result in a dramatic color change from red to colorless
Fig. 1a), which can be easily detected by the naked-eyes. In the cor-
3
, HCO
3
, HSO
4
, SO
4
, HS , HSO
, and cystein−e
−
ference capacity of sensor 3TI for CN against all kinds of analytes.
(
−
To get insight into the CN (1.0 μM) sensing property of sensor 3TI,
the fluorescence titration experiment was carried out with different
(
−
2
concentrations of CN in THF/H O (3/7, v/v) solution. As shown in
responding UV–Vis spectra, the absorption band at 512 nm (ICT)
completely disappeared and a new strong band at 378 nm appeared
−
Fig. 4, upon gradual addition of CN (0–10 equiv.), a prominent
fluorescent enhancement at 588 nm accompanied by a blue shift of
(
Fig. 1b). These obvious changes indicate that the nucleophilic addition
−
of CN to the electron deficient part of 3TI results in inhibition of ICT
−
−
−
−
transition. However, other tested analytes (F , Cl , AcO , NO
3
,
−
2−
−
−
2−
−
−
SCN , CO
3
, HCO
3
, HSO
4
, SO
4
, HS , HSO
3
and Cys) induced
almost no significant change in color and absorption spectra (Fig. 1b).
These observations reveal that 3TI can be used as a good colorimetric
−
sensor for CN in aqueous media.
−
Fig. 2 shows the fluorescence response of sensor 3TI toward CN
.
The free sensor 3TI exhibited a very weak fluorescence emission band
at 643 nm upon excitation at 390 nm in THF/H O (3:7, v/v) solution.
2
−
The only significant response was observed when CN (10 equiv.) was
added. A prominent fluorescent enhancement at 588 nm (37-fold) was
clearly observed and the band at 643 nm (ICT) diminished, which re-
sponded with an obvious color change from red to bright green under
−
UV lamp (Fig. 2b). This can be explained by that CN acted as a good
nucleophile attacks to the electrophilic center of the 3TI to suppress the
π-conjugation resulting in distinct change in solution color and fluor-
escence. However, other examined analytes (10 equiv.) did not lead to
any significant change in solution color and fluorescence spectra of 3TI,
−
demonstrating that 3TI could effectively sense CN in aqueous solution
with high selectivity.
−
Fig. 3. Competitive experiments of 3TI (1.0 μM) for CN (10.0 equiv.) in the
2
presence of common analytes (10.0 equiv.) in THF/H O (3:7, v/v) solution.
Excitation wavelength at 390 nm, emission wavelength at 588 nm.
669

Z. Guo et al.
Dyes and Pigments 163 (2019) 667–674
Fig. 4. Fluorescence titration of sensor 3TI (1.0 μM) with the gradual increasing
Fig. 6. 1H NMR spectra (400 Hz, DMSO-d
presence of CN (0.5 equiv. and 1.0 equiv.).
6
) of sensor 3TI in the absence and
−
of concentrations of CN anions (0–10.0 equiv.). Inset: Fluorescence calibra-
−
−
tion curve at 588 nm of 3TI as a function of the CN
.
8
.22 ppm, which completely disappeared upon the addition of 1.0
−
equiv. of CN , while a new signal emerged at 4.85 ppm, which corre-
sponds to the β-proton of 1,3-indenedione-vinyl group (HK’). Mean-
while, the aromatic proton signals showed substantial upfield shifts
compared to those of sensor 3TI due to breaking of the conjugation.
−
These results indicated that CN attacks the β-conjugated position of
1,3-indenedione-vinyl moiety of sensor 3TI and the formation of cya-
–
nide adduct (3TI-CN ). The interaction mechanism between 3TI and
CN was also supported by FTIR measurements (Fig. S5). In the pre-
sence of CN (1.0 equiv), it was clearly observed that the characteristic
−
−
stretching band for the saturated hydrocarbon (CH) group appeared at
−1
−1
2956 and 2881 cm
and a new absorption peak at 2143 cm
ob-
served corresponding to the C≡N group. Meanwhile, the C=C
−1
stretching frequency of the 1,3-indenedione-vinyl moiety at 1676 cm
completely disappeared and the stretching vibration absorption peak of
−
1
amide (C=O) shifted from 1721 to 1687 cm . These findings strongly
−
proved that the coordination undergo the nucleophilic addition of CN
to 1,3-indenedione-vinyl group. In addition, the formation of the cor-
–
responding 3TI-CN adduct was further confirmed by HR ESI-MS ana-
Fig. 5. The linear relationship between fluorescence intensity at 588 nm and
−
lysis (Fig. S6), where the peak at m/z 430.9075 (calc. = 431.0108)
the concentrations of CN
.
–
+
corresponding to [3TI-CN + H] was clearly observed, the signal at
m/z = 449.0273 (m/z calcd. = 449.0214) corresponds to [3TI-
5
5 nm from 643 to 588 nm, and the fluorescent intensity of sensor 3TI
–
+
CN + H
2
O] , and an obvious signal at m/z = 493.0505 appeared,
−
at 588 nm gradually increased with the increased of CN (Fig. 4, inset),
indicating that the ICT process was hampered by the nucleophilic attack
of CN to the vinyl group of sensor 3TI. The increase in emission in-
coinciding exactly with that for the adduct species of [3TI-
–
− +
CN + NO
3
]
(m/z calcd. = 492.9987).
−
Based on these observations, the proposed sensing mechanism was
−
tensity at 588 nm as a function of [CN ] was found to be good linear for
−
the nucleophilic addition of CN to 3TI (Scheme 2), which efficiently
−
2
[
CN ] of 0–10 μM with regression coefficient of R = 0.99316 (Fig. 5),
hampered the ICT process [41–43], and thus caused the solution dra-
matic naked-eye detectable color changes, large enhancement of
emission and the optical spectral blue shift.
−
suggesting the good fluorescent sensing ability of 3TI for CN in aqu-
−
eous media. The detection limit (DL) of 3TI for CN by the fluorescence
spectra changes was calculated to be 31.3 nM based on 3δ/S [38,39],
which is much lower than the WHO detection level (1.9 μM) [7] and the
−
3.5. Theoretical calculations
US EPA established the Maximum Contaminant Level (MCL) for CN in
drinking water to be 2.0 μM [40]. Thus, these results indicated that
−
To further gain insight into the sensing mechanism of the color
bleaching and fluorescence off-on behavior of 3TI in the presence of
sensor 3TI can be used to detect low concentration of CN in practical
application.
−
3.4. Sensing mechanism of sensor 3TI toward CN
−
To get insight into the sensing mechanism of the sensor 3TI to CN
,
−
1
the reaction product of 3TI with CN was investigated by H NMR and
FTIR spectra. Fig. 6 shows the H NMR spectra date before and after
1
cyanide anion addition in DMSO-d
of CN caused a slow reduction of the vinyl proton signal (H ) at
6
at room temperature. The addition
−
−
Scheme 2. The proposed mechanism of sensor 3TI for CN detection.
K
670

Z. Guo et al.
Dyes and Pigments 163 (2019) 667–674
Fig. 7. Optimized structures of 3TI and 3TI-CN–.
−
CN , the computer calculations were carried out by B3LYP/6-31G*
−
method. Fig. 7 shows the optimized geometries of 3TI and 3TI-CN
.
Fig. 9. The pH dependence of the fluorescence intensity of 3TI at 588 nm with
and without CN (10.0 equiv.).
−
Sensor 3TI is nearly planar with efficient π-conjugation and which is
the reason for efficient ICT transition from oligothiophene moiety to
,3-indenedione-vinyl group. Upon interaction with CN , the geometry
of the sensor molecule changes to the twisted form with a dihedral
angle of 47.86° between the oligothiophene and 1,3-indenedione-vinyl
groups and as a result π-conjugation breakdown, leads to decrease ICT
effects. The interruption of the π-conjugation caused a significant blue
shift in fluorescence emission spectra and effectively decreased the ICT
character. These DFT results clearly revealed the nucleophilic addition
−
1
a serious problem that sensors often encounter. In our study, the re-
−
sponse of 3TI towards CN was found to be very fast. The fluorescence
intensity increased at 588 nm and then reached maximum within 30 s
−
in presence of 10 equiv. of CN , indicating that the nucleophilic ad-
−
dition reaction between the vinyl group of sensor 3TI and CN was
−
completed (Fig. 9), denoting the rapid reaction of sensor 3TI with CN
Thus, sensor 3TI can be used to monitor CN in real time.
.
−
−
2
of CN to the β-position of C=C and conversation of sp hybridized
For potential applicability, the pH dependent emission spectral
3
carbon to sp hybridization.
−
changes of the sensor 3TI (1.0 μM) in absence and presence of CN (10
Detailed information about the noted absorption in the blue shift
upon the addition of CN with 3TI can also be gained TD-DFT calcu-
lations. As shown in Fig. 8, the calculated absorption wavelengths of
TI and 3TI-CN were 495 nm and 386 nm, respectively, which is in
good agreement with the experimental results. Moreover, the HOMO-
LUMO energy gap is significantly increased in 3TI-CN adduct
3.21 eV) compared to 3TI (2.64 eV), which is well reflected in the
changes in UV–vis spectra. Therefore, the DFT and TD-DFT calculations
provide reasonable explanations for their electronic structure and op-
tical spectra.
2
equiv.) in THF/H O (3/7, v/v) solution were investigated as shown in
−
Fig. 10. In different pH conditions (1–14), the fluorescence intensity of
−
the sensor 3TI is almost unaffected in absence of CN . In presence of
−
3
−
CN , there is a significant enhancement of fluorescence intensity at a
range of pH values from 5 to 12. The results indicate that 3TI can
−
−
−
successfully react with CN and allow CN detection over a wide pH
(
range (5–12), and functions properly at physiological pH.
3.7. Practical applications
Since 3TI features excellent selectivity, high sensitivity, naked-eye
colorimertic and fluorogenic dual responses, instant response time, and
excellent anti-interference ability for CN in favorable working pH
3
.6. Response time and effect of pH
−
To exploit its sensing behavior, we examined the time dependent
range, it is quite possible to explore its practical applications.
changes in the fluorescence spectra of 3TI (1.0 μM) upon reaction with
CN (10 equiv.) at room temperature. Reaction-based sensors generally
−
−
Firstly, we set out to investigate the recognition of CN by 3TI
suffer from a long response time. As well known, a long response time is
Fig. 8. Frontier molecular orbitals of 3TI and 3TI-CN–.
Fig. 10. The response time of sensor 3TI for CN .
−
671

Z. Guo et al.
Dyes and Pigments 163 (2019) 667–674
−
Fig. 12. Solution color changes under 365 nm UV lamp of sensor 3TI to monitor
cyanide in food samples. (For interpretation of the references to color in this
figure legend, the reader is referred to the Web version of this article.)
Fig. 11. Color change of silica containing sensor 3TI for CN detection under
ambient and 365 nm UV light. (For interpretation of the references to color in
this figure legend, the reader is referred to the Web version of this article.)
centrifuging them to obtain the target cyanide-containing solutions.
while supported on silica [44]. A solution of 3TI in THF (1 mL, 10 μM)
was added to silica (200–300 mesh, 2 g, colorless), stirred for 1 min,
and then the solvent was removed to gain the pink silica (Fig. 11). The
The addition of 1.0 equiv. of each filtrate to the sensor 3TI (1.0 μM),
−
which gives green color and is similar to that of CN anion complex of
−
−
3TI (Fig. 12). The qualitative estimation of CN from real food samples
pink silica was treated with a solution of CN (10 μL, 1.0 mM) in
by using the colorimetric anion sensor 3TI is an interesting and easy
process, which gives rapid response through the naked-eye identifica-
tion.
deionized water. An instant color change from pink to colorless in the
−
case of CN was noticed. The solvent was removed under reduced
pressure, and the silica sample was dried in an oven to obtain the ex-
pected material. Since the color change from the pink to colorless was
rapidly and clearly detected, sensor 3TI has the great potential for use
in practical application served as an optical solid sensor [45].
Furthermore, fluorescent dyes in cellular biology have become one
of the most popular methods for biological analysis since it is a non-
destructive way of tracking and analyzing biological molecules [46].
Therefore, to evaluate potential biological applications, the sensor 3TI
−
Subsequently, the sensor 3TI was used to detect CN in real en-
−
−
as a fluorescent dye for the detection of CN in living cells was tested.
vironmental water samples. Sensor 3TI sensitivity to CN detection in
The cytotoxicity of sensor 3TI was measured by MTT assay with in-
creasing sensor concentration (Fig. S7). The investigated results in-
dicated that the sensor 3TI exhibited low cytotoxicity to living cells.
Then HeLa cells were chosen as a representative cell line and fluor-
escent images were recorded under fluorescence microscope. Initially,
the incubation of HeLa cells with 3TI caused almost no fluorescence
emission under green field (Fig. 13a and b). Afterwards, a time-course
experiment was carried out to monitor the binding process of sensor 3TI
to determine intracellular CN . When CN was added to HeLa cells
and further incubated with sensor 3TI for 30 min, a green fluorescence
was clearly observed (Fig. 13c). As the incubation time was prolonged
to 60 min, a bright green fluorescence was identified in the cytoplasm
real water samples such as tap water, distilled water, and lake water
from Jinan Garden Expo was evaluated by standard addition method.
The analytical results were summarized in Table 1. The sensor 3TI was
−
able to detect the spiked CN with good recovery ranged from 98.9% to
100.3% and low relative standard deviation (RSD) below 0.9%, in-
dicating the feasibility and reliability of the sensor for determination of
−
CN in environmental water samples. These results ulteriorly proved
that 3TI could act as a potential, simple, effective and convenient
−
−
−
fluorescent sensor to detect CN in real samples with satisfactory and
acceptable results.
Moreover, to further evaluate the practical application of 3TI for
−
detecting CN in human life, the cassava, bitter seeds, green taroes,
sprouting and green potatoes were utilized by infusing these food
samples in aqueous sodium hydroxide and then filtrating and
Table 1
−
Measurement results of CN in environmental water samples.
Found(x ± SDb)
a
Recovery (%) Relative
error
RSD (%)
Sample
Added
(
× 107 M) ( × 10 M)
7
(
%)
Distilled
−c
–
–
–
–
Water 10
9.98 ± 0.09
15.04 ± 0.12
19.97 ± 0.06
–
99.8
100.3
99.9
–
0.2
0.27
0.1
–
0.9
0.79
0.3
–
1
2
–
5
0
River
Water 10
9.94 ± 0.07
14.93 ± 0.08
19.79 ± 0.06
–
99.4
99.5
98.9
–
0.56
0.47
1.05
–
0.71
0.54
0.3
–
1
2
–
5
0
Tap
Water 10
9.97 ± 0.03
14.95 ± 0.06
19.88 ± 0.13
–
99.7
99.6
99.4
–
0.3
0.33
0.6
–
0.3
0.4
0.65
–
1
2
–
5
0
Lake
Water 10
9.96 ± 0.06
14.85 ± 0.12
19.83 ± 0.07
99.6
99
99.1
0.4
1
0.85
0.6
0.81
0.35
1
2
5
0
a
b
c
Fig. 13. Confocal microscopy images of HeLa cells. (a) Fluorescent images of
HeLa cells with 3TI for 1 h; (b) Bright-field image; (c) Fluorescent images of
HeLa cells incubated with 3TI and CN for 30 min; (d) for 60 min.
Mean of three determination.
SD: Standard Deviation.
−
-
:No substance added.
672

Z. Guo et al.
Dyes and Pigments 163 (2019) 667–674
[12] Lou X, Ou D, Li Q, Li Z. An indirect approach for anion detection: the displacement
strategy and its application. Chem Commun 2012;48:8462–77.
[13] Yang Y, Zhao Q, Feng W, Li FY. Luminescent chemodosimeters for bioimaging.
Chem Rev 2013;113:192–270.
−
(
Fig. 13d), implying that 3TI has a very good performance for CN
imaging in HeLa cells. These cell imaging results suggest that this
simple sensor 3TI can be used for fluorescence imaging of CN selec-
−
tively and sensitively in living cells.
[14] Niu Q, Sun T, Li T, Guo Z, Pang H. Highly sensitive and selective colorimetric/
fluorescent probe with aggregation induced emission characteristics for multiple
targets of copper, zinc and cyanide ions sensing and its practical application in
water and food samples. Sens Actuators B 2018;266:730–43.
−
Compared to other CN -selective sensors (Table S1) [47–52], our
designed sensor possessed multiple attractive features including color-
imertic and turn-on fluorescent dual-mode detection, excellent anti-
interference ability, low detection limit, naked-eye observed color
changes, obvious optical spectra changes, fast response time, favorable
[15] Peng M, Guo Y, Yang X, Wang L, An J. A highly selective ratiometric and colori-
metric chemosensor for cyanide detection. Dyes Pigments 2013;98:327–32.
[
16] Sun Y, Wang G, Guo W. Colorimetric detection of cyanide with N-ni-
trophenylbenzamide derivatives. Tetrahedron 2009;65:3480–5.
17] Wang F, Wang L, Chen X, Yoon J. Recent progress in the development of fluoro-
metric and colorimetric chemosensors for detection of cyanide ions. Chem Soc Rev
2014;43:4312–24.
−
working pH range, good validity for signaling CN on silica and in real
[
water and food samples analysis, good cell membrane permeability and
−
low cytotoxicity for imaging CN in living cells.
[
18] Hong SJ, Yoo J, Kim SH, Yoon J, Lee CH. Beta-vinyl substituted calix[4]pyrrole as a
selective ratiometric sensor for cyanide anion. Chem Commun (J Chem Soc Sect D)
2009;2:189–91.
4. Conclusions
[
19] Yang L, Li X, Yang J, Qu Y, Hua J. Colorimetric and ratiometric near-infrared
fluorescent cyanide chemodosimeter based on phenazine derivatives. ACS Appl
Mater Interfaces 2013;5:1317–26.
In summary, we reported a new oligothiophene-indenedione-based
colorimetric and fluorescent turn-on sensor 3TI for rapid naked-eye
detection of CN anions in 70% aqueous solution with excellent overall
[20] Lee CH, Yoon HJ, Shim JS, Jang WD. boradiazaindacene-based turn-on fluorescent
probe for cyanide detection in aqueous media. Chem Eur J 2012;18:4513–6.
−
[
21] Liu Z, Wang X, Yang Z, He W. Rational design of a dual chemosensor for cyanide
anion sensing based on dicyanovinyl-substituted benzofurazan. J Org Chem
2011;76:10286–90.
performance, such as naked-eye observed color changes, remarkable
fluorescence enhancement, simple procedure, high sensitivity, excellent
anti-interference ability, rapid response, favorable working pH span,
[
22] Niu Q, Lan L, Li T, Guo Z, Jiang T, Zhao Z, Feng Z, Xi J. A highly selective turn-on
fluorescent and naked-eye colorimetric sensor for cyanide detection in food samples
and its application in imaging of living cells. Sens Actuators B 2018;276:13–22.
−
and good validity for signaling CN on silica and in real water and food
samples. Moreover, the detection mechanism was a nucleophilic addi-
[23] Lan L, Li T, Wei T, Pang H, Sun T, Wang E, Liu H, Niu Q. Oligothiophene-based
colorimetric and ratiometric fluorescence dual-channel cyanide chemosensor: sen-
sing ability, TD-DFT calculations and its application as an efficient solid state
sensor. Spectrochim Acta A 2018;193:289–96.
−
tion reaction between the sensor 3TI and CN , which inhibited the ICT
1
process as confirmed by optical analysis, H NMR titration, and FTIR
spectra, HR ESI-MS analysis as well as the TD/DFT studies. Benefiting
from the good water-solubility and good biocompatibility of the 3TI,
[
24] Bera MK, Chakraborty C, Singh PK, Sahu C, Sen K, Maji S, Das AK, Malik S.
Fluorene-based chemodosimeter for “turn-on” sensing of cyanide by hampering
ESIPT and live cell imaging. J Mater Chem B 2014;2:4733–9.
−
this sensor can be applied for subcellular imaging of CN in living cells
[
25] Dvivedi A, Rajakannu P, Ravikanth M. meso-Salicylaldehyde substituted BODIPY as
a chemodosimetric sensor for cyanide anions. Dalton Trans 2015;44:4054–62.
26] Niamnont N, Khumsri A, Promchat A, Tumcharern G, Sukwattanasinitt M. Novel
salicylaldehyde derivatives as fluorescence turn-on sensors for cyanide ion. J
Hazard Mater 2014;280:458–63.
with good cell membrane permeability and low cytotoxicity.
[
Acknowledgments
[
27] Pati PB, Zade SS. Selective colorimetric and “Turn-on” fluorimetric detection of
cyanide using a chemodosimeter comprising salicylaldehyde and triphenylamine
groups. Eur J Org Chem 2012;33:6555–61.
We are thankful for the financial support from the National Natural
Science Foundation of China (Nos. 21376125, 21776143, and
[
28] Huang X, Gu X, Zhang G, Zhang D. A highly selective fluorescence turn-on detection
of cyanide based on the aggregation of tetraphenylethylene molecules induced by
chemical reaction. Chem Commun (J Chem Soc Sect D) 2012;48:12195–7.
29] Shankar BH, Jayaram DT, Ramaiah D. A reversible dual mode chemodosimeter for
the detection of cyanide ions in natural sources. Chem Asian J 2014;9:1636–42.
30] Shiraishi Y, Nakamura M, Yamamoto K, Hirai T. Rapid, selective, and sensitive
fluorometric detection of cyanide anions in aqueous media by cyanine dyes with
indolium–coumarin linkages. Chem Commun (J Chem Soc Sect D)
51702178), the Natural Science Foundation of Shandong Province (No.
ZR2017LB009), the program for National College Students' Innovation
and Entrepreneurship Training (No. 201710431027), and the Program
for Scientific Research Innovation Team in Colleges and Universities of
Shandong Province.
[
[
2
014;78:11583–6.
31] Wang S, Xu H, Yang Q, Song Y, Li Y. A triphenylamine-based colorimetric and
turn-on” fluorescent probe for detection of cyanide anions in live cells. RSC Adv
Appendix A. Supplementary data
[
[
“
Supplementary data to this article can be found online at https://
doi.org/10.1016/j.dyepig.2018.12.057.
2015;59:47990–6.
32] Sun T, Niu Q, Li Y, Li T, Hu T, Wang E, Liu H. A novel oligothiophene-based col-
orimetric and fluorescent “turn on” sensor for highly selective and sensitive de-
tection of cyanide in aqueous media and its practical applications in water and food
samples. Sens Actuators B 2018;258:64–71.
33] Pramanik S, Bhalla V, Kumar M. Hexaphenylbenzene-based fluorescent aggregates
for ratiometric detection of cyanide ions at nanomolar level: set–reset memorized
sequential logic device. ACS Appl Mater Interfaces 2014;6:5930–9.
34] Cheng J, Liang X, Cao Y, Guo K, Wong WY. Aldehyde end-capped terthiophene with
aggregation-induced emission characteristics. Tetrahedron 2015;71:5634–9.
35] Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR,
Scalmani G, Barone V, Mennucci B, Petersson GA. Gaussian 09, revision A.2.
Wallingford CT: Gaussian, Inc.; 2009.
References
[
[
[
1] Vennesland B, Conn EE, Knownles CJ, Westly J, Wissing F. Cyanide in biology.
London: Academic Press; 1981.
2] Young CA, Twidwell LG, Anderson CG, Minerals M, Staff MS, Minerals M, Meeting
MS. Cyanide: social, industrial, and economic aspects, TMS (the minerals. Metals &
Materials Society); 2001.
[
[
[
[
[
[
3] Bolarinwa IF, Orfila C, Morgan MRA. Determination of amygdalin in appleseeds,
fresh apples and processed apple juices. Food Chem 2015;170:437–42.
4] Miller GC, Pritsos CA. Cyanide: soc., Ind. Econ. Aspects. Proc Symp Appl Math
[
36] Becke AD. Density-functional thermochemistry. III. The role of exact exchange. J
Chem Phys 1993;98:5648–52.
2
001:73–81.
[
37] Hehre WJ, Ditchfield R, Pople JA. Self-consistent molecular orbital methods. XII.
Further extensions of Gaussian-type basis sets for use in molecular orbital studies of
organic molecules. J Chem Phys 1972;56:2257–61.
5] Kaim W, Schwederski B, Klein A. Bioinorganic chemistry – inorganic elements in the
chemistry of life: an introduction and guide. Wiley; 2013.
6] WHO guidelines for drinking-water quality: recommendations. World Health
[
[
38] Jo TG, Na YJ, Lee JJ. A multifunctional colorimetric chemosensor for cyanide and
Organization; 2004.
copper(II) ions. Sens Actuators B 2015;211:498–506.
[
[
7] Guidelines for drinking-water quality. Geneva: World Health Organization; 1996.
8] Sun Y, Zhao H, Boussouar I, Zhang F, Tian D, Li H. Highly sensitive chiral sensing by
calix[4]arene-modified silvernanoparticles via dynamic light scattering. Sens
Actuators B 2015;216:235–9.
39] Yoo M, Park S, Kim HJ. Highly selective detection of cyanide by 2-hydro-
xyphenylsalicylimine of latent fluorescence through the cyanide-catalyzed imine–-
to–oxazole transformation. Sens Actuators B 2015;220:788–93.
40] Table of regulated drinking water contaminants Washington, DC, USA https://
www.epa.gov/ground-water-and-drinkingwater/table-regulated-drinking-water-
contaminants.
41] Cheng XH, Tang RL, Jia HZ, Feng J, Qin JG, Li Z. New fluorescent and colorimetric
probe for cyanide: direct reactivity, high selectivity, and bioimaging application.
Appl. Mater. Interfaces. 2012;4:4387–92.
42] Yang L, Li X, Yang JB, Qu Y, Hua JL. Colorimetric and ratiometric Near-Infrared
fluorescent cyanide chemodosimeter based on phenazine derivatives. Appl. Mater.
[
[
[
[9] Sun Y, Ma J, Tian D, Li H. Macroscopic switches constructed through host-guest
chemistry. Chem Commun 2016;52:4602–12.
[
10] Zhou X, Kim J, Liu Z, Jo S, Pak YL, Swamy KMK. Selective fluorescent and col-
orimetric recognition of cyanide via altering hydrogen bonding interaction in
aqueous solution and its application in bioimaging. Dyes pigm 2016;128:256–62.
11] Xu Z, Chen X, Kim HN, Yoon J. Sensors for the optical detection of cyanide ion.
Chem Soc Rev 2010;39:127–37.
[
673

Z. Guo et al.
Dyes and Pigments 163 (2019) 667–674
Interfaces. 2013;5:1317–26.
43] Fillaut J-L, Akdas-Kilig H, Dean E, Latouche C, Boucekkine A. Switching of reverse
A novel and synthetically facile coumarin-thiophene-derived Schiff base for selec-
tive fluorescent detection of cyanide anions in aqueous solution: synthesis, anion
interactions, theoretical study and DNA-binding properties. Tetrahedron
2018;74:6897–906.
[
charge transfers for a rational design of an OFF-ON phosphorescent chemodosi-
meter of cyanide anions. Inorg Chem 2013;52:4890–7.
[44] Jo TG, Na YJ, Lee JJ. A multifunctional colorimetric chemosensor for cyanide and
copper(II) ions. Sens Actuators B 2015;211:498–506.
[49] Long C, Hu J-H, Ni P-W, Yin Z, Fu Q-Q. A novel colorimetric and ratiometric
−
fluorescent CN sensor based on rhodamine B hydrazone derivatives in aqueous
[
45] Yoo M, Park S, Kim HJ. Highly selective detection of cyanide by 2-hydro-
xyphenylsalicylimine of latent fluorescence through the cyanide-catalyzed imine–-
to–oxazole transformation. Sens Actuators B 2015;220:788–93.
media and its application in sprouting potatoes. New J Chem 2018;42:17056–61.
[50] Orojloo M, Amani S. Naked-eye detection of cyanide ions in aqueous media based
on an azo-azomethine chemosensor. C. R. CHIM. 2017;20:415–23.
[
46] Yang Y, Zhao Q, Feng W, Li F. Luminescent chemodosimeters for bioimaging. Chem
Rev 2013;113:192–270.
[51] Thanayupong E, Suttisintong K, Sukwattanasinitt M, Niamnont N. Turn-on fluor-
escent sensor for the detection of cyanide based on a novel dicyanovinyl phenyla-
cetylene. New J Chem 2017;41:4058–64.
[47] Li Z, Liu C, Wang S, Xiao L, Jing X. Visual detection of cyanide ion in aqueous
medium by a new chromogenic azo-azomethine chemosensor. Spectrochim Acta A
[52] Sun Y, Hu J-H, Qi J, Li J-B. A highly selective colorimetric and “turn-on” fluori-
−
2
019;210:321–8.
metric chemosensor for detecting CN based on unsymmetrical azine derivatives in
[48] Chemchem M, Yahaya I, Aydiner B, Seferoğlu N, Doluca O, Merabet N, Seferoğlu Z.
aqueous media. Spectrochim Acta A 2016;167:101–5.
674