A sensitive BODIPY-based fluorescent probe for detecting endogenous hydroxyl radicals in living cells

Article abstract of DOI:10.1039/d0ra05378c

The hydroxyl radical (OH) has been suggested to play very vital roles in many physiological and pathological processes. However, selective detection of OH is highly challenging owing to its extremely high reactivity and short lifetime. Herein, we designed and synthesized a sensitive "turn on"fluorescent probe for detecting endogenous OH based on a BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) platform. The probe had shown good properties including high sensitively, ideal selectively and low cytotoxicity, and was successfully employed to image endogenous hydroxyl radical in living cells.

Full text of DOI:10.1039/d0ra05378c

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PAPER
A sensitive BODIPY-based fluorescent probe for
detecting endogenous hydroxyl radicals in living
cells†
Cite this: RSC Adv., 2020, 10, 28705
* *
Yongqiang Chen and Xiaoqing Wei
Xingyu Qu,
Yongjun Bian,
The hydroxyl radical (cOH) has been suggested to play very vital roles in many physiological and pathological
processes. However, selective detection of cOH is highly challenging owing to its extremely high reactivity
and short lifetime. Herein, we designed and synthesized a sensitive “turn on” fluorescent probe for detecting
endogenous cOH based on a BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) platform. The probe
had shown good properties including high sensitively, ideal selectively and low cytotoxicity, and was
successfully employed to image endogenous hydroxyl radical in living cells.
Received 19th June 2020
Accepted 29th July 2020
DOI: 10.1039/d0ra05378c
rsc.li/rsc-advances
organic small molecules are one of the most successful species
owing to easily modied, high sensitive and nontoxic or low
Introduction
toxic. As one of the important organic uorophores, 4,4-
diuoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) with relatively
high uorescence quantum yields, high extinction coefficient
and good photostability, have drawn increasing attention.25–31
To construct high sensitive and selective probes for detecting
hydroxyl radical, a general strategy is to conjugate an organic
uorescence molecule with a recognition element moiety for
specically trapping and reacting with cOH. For example, Wang
et al. reported a BODIPY probe with gem-dichloro moiety
reacting with cOH via a substitute reaction and showed good
selectivity and biocompatibility for cellar imaging of hydroxyl
radical in live cells.32 The oxidation potential of cOH is around
2.8 eV (ref. 3) and high enough to oxidize Ph3P (the reduction
electrode potential is 2.7 eV) to Ph3P]O. But other reactive
oxygen species (ROS), such as H2O2, O2cꢀ, ClOꢀ, are failure for
this oxidation process. Based on this mechanism, a high
selective and biocompatible BODIPY probe with Ph3P moieties
was reported by our group in 2018.33 Herein, on the basis of
above work, we continually designed and synthesized a novel
“turn-on” NIR uorescent probe for monitoring cOH with
a much improved solubility in aqueous solution, which also
showed high selectivity toward cOH over other reactive oxygen/
nitrogen species (ROS/RNS) and has been successfully applied
to detect cOH for imaging in living cells.
The hydroxyl radical (cOH), an unstable and highly reactive
molecule, has aroused growing attention in the past decades. It
has been widely used in many areas of human health, including
drinking water treatment,1–3 air quality monitoring,4 cancer
treatment,5 etc. Normal levels of cOH in cells play critical roles in
regulating many physiological and pathological events.
However, excessive cOH is extremely harmful to human health
and leads to a series of physiological diseases like aging and
Parkinson's disease by reacting with numerous bio-
macromolecules including DNA bases, lipids, and proteins.6
Therefore, rapid, sensitive and accurate detection of intracel-
lular cOH concentration is of vital importance in order to well
understand its biological impact and timely hamper its damage.
Whereas, selectively monitoring cOH is very difficult due to its
short life-time (about 10ꢀ9 s).
For cOH detection, many analytic methods have been
applied, such as electron spin resonance spectroscopy,7,8 chro-
matography,9 chemiluminescence10,11 and electrochemistry.12–14
Nevertheless, most of them either require expensive instru-
ments or are not sensitive enough towards cOH and not suitable
for monitoring cOH in live cells. By comparison, uorescence-
based ways might be a better choice because of these prom-
inent advantages like simplicity, high sensitivity, high-speed
spatial analysis, low bio-damaging, real-time monitoring in
live cells, etc. Indeed, several uorescence probes have been
developed during the past few years, for instance, organic small
molecules,15–20 semiconductor quantum dots21–23 and metal
nanoclusters.24 Among them, the uorescence probes based on
Results and discussion
Design and synthesis of the probe 1 and compound OX-1
The synthesis of probe 1 was accomplished through a three-step
route depicted in Scheme 1. 3,4-Dihydroxybenzaldehyde was
alkylated with 1-bromohexadecane to afford compound 3.
Compound 3 reacted with 2,4-dimethyl-pyrrole to generate
compound 2 in moderate yield. The target uorescent probe 1
College of Chemistry and Chemical Engineering, Jinzhong University, Yuci 030619,
China. E-mail: yjbian2013@jzxy.edu.cn; chenyongqiang@jzxy.edu.cn
† Electronic supplementary information (ESI) available. See DOI:
10.1039/d0ra05378c
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Fig. 1 UV-Vis absorption (black line) and fluorescence spectra (red
line) of probe 1 (10 mmol Lꢀ1) in CH2Cl2 solvent.
Scheme
1 Synthetic routes for the preparation of probe 1 and
compound OX-1. (a) C16H33Br, K2CO3, KI, in DMF; (b) 2,4-dimethyl-
pyrrole and trifluoroacetic acid in CH2Cl2; (c) DDQ; (d) triethylamine,
BF3$OEt2; (e) 2-(diphenylphosphino)benzaldehyde, AcOH, piperidine;
(f) Fenton's reagent.
properties of the compound OX-1 were similar, except the
uorescence quantum yield. The uorescence quantum yield of
probe 1 was 0.26 in dimethyl sulfoxide (DMSO) and about 0.67
in other organic solvents. Whereas, the uorescence quantum
yield of compound OX-1 was above 0.62 in all organic solvents.
These results indicated that probe 1 with high molar extinction
coefficient probably can be used as a turn-on uorescence
sensor for monitoring cOH.
was prepared by Knoevenagel condensation of compound 2 and
2-(diphenylphosphino)benzaldehyde. Compound OX-1 was
synthesized by Fenton reaction with probe 1. Both probe 1 and
compound OX-1 were characterized by MALDI-TOF MS, 1H
NMR, 13C NMR and 31P NMR.
Fluorescence detection and selectivity of probe 1
Spectral properties of the probe 1 and compound OX-1
The good uorescence properties of probe 1 suggest it prom-
The probe 1 based on BODIPY dyes using triphenylphosphine ising potential as uorescence sensors. The uorescence
as a reactive-site tends to show good uorescence properties responses of probe 1 with ROS/RNS radicals were investigated
and potential sensing application for detecting cOH. Hence, in DMSO solution as shown in Fig. 2. Upon addition of cOH
with the probe 1 and compound OX-1 in hand, their spectral (0.1 mmol Lꢀ1), the uorescence intensity of probe 1 at 650 nm
properties were rstly examined. The photo-physical properties increased remarkably. The addition of a series of different ROS/
of probe 1 and compound OX-1 in various solvents were inves- RNS radicals (1.2 mmol Lꢀ1), such as H2O2, ClOꢀ, O2cꢀ, TBHP,
tigated at ambient temperature and summarized in Tables 1 NO, NO2ꢀ, Vc, Fe3+, GSH, respectively, did not generate similar
and S1,† and the UV/Vis absorption and emission spectra of enhancement and nearly unchanged. The above results
probe 1 in CH2Cl2 solvent were showed in Fig. 1. Probe 1 could demonstrated that its cOH response was not interfered in the
be completely dissolved in organic solvents and the absorption background containing appropriate ROS/RNS radicals.
spectra were slightly varied with increasing the solvent polari-
The titration experiments were also carried out to further
ties. The absorption band of probe 1 was centered at 630 nm, assess the sensing ability of probe 1 towards cOH. The sensing
570 nm and 349 nm, and exciting at 580 nm, strong emissions process was operated by gradually increasing cOH concentra-
typical for the BODIPY uorescence dyes was observed at tion in the DMSO solution containing the probe 1 (10 mmol Lꢀ1
)
650 nm. Compared with these of probe 1, the photo-physical as shown in Fig. 3. Aer adding cOH from 0 to 5 equivalent, the
Table 1 Optical properties of 1 and OX-1 in CH2Cl2 and DMSO solvents at 298 K
lu
Compounds
Solvents
lambasx (nm)/log 3max
(nm)
Dl1/2a [nm]
Ffb
sfc (nm)
1
CH2Cl2
DMSO
CH2Cl2
DMSO
633/4.93, 574/4.52, 349/4.68
628/4.93, 581/4.56
630/4.92, 574/4.53, 355/4.70
630/4.92, 577/4.53
650
650
646
647
29
30
27
26
0.67
0.26
0.63
0.62
4.68
—
4.24
—
OX-1
a
b
Half width at maximum height. Fluorescence quantum yield. c Fluorescence lifetimes.
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Practical application of probe 1
Having evaluated the ability of probe 1 to detect cOH in living
cells, rstly, we checked its cytotoxicity by monitoring the
survival rate of HeLa cells incubation with probe 1 aer 5 h over
a wide range of concentrations (0–200 mmol Lꢀ1) according to
the MTT viability assay (Fig. S17, ESI†). The results indicated
that the HeLa cells maintained a high viability (>80%) aer they
had been incubated with 50 mmol Lꢀ1 probe 1, therefore, clearly
could be used as intracellular luminescent probes. And then the
ability of probe 1 to detect cOH was examined by using phorbol
12-myristate 13-acetate (PMA). In this experiment, HeLa cells
were incubated with 10 mmol Lꢀ1 probe 1 for 30 min before PMA
stimulation, and the uorescence signal was very weak upon
excitation at 633 nm (Fig. 4a and c). However, the uorescence
signal increased aer PMA stimulation for 1 h (Fig. 4d and f).
These results demonstrate that probe 1 can be used for
detecting intracellular cOH.
Fig. 2 Fluorescence reactivity of probe 1 (10 mmol Lꢀ1 in DMSO) with
various ROS/RNS species (0.1 mmol Lꢀ1 of cOH, 1.2 mmol Lꢀ1 of H2O2,
ClOꢀ, O2cꢀ, TBHP, NO, NO2ꢀ, Vc, Fe3+, GSH) upon excitation at
580 nm. I and I0 were the fluorescence intensity of the probe in the
presence and absence of various ROS/RNS species.
Materials and methods
Reagents and instruments
uorescence intensity of probe 1 have increased remarkably
with a virtually unchanged peak position upon excitation at
580 nm. Based on the triple signal-to-noise ratio, the detection
limit of probe 1 for cOH is determined as 0.05 mmol Lꢀ1. The
good linear relationship between the uorescence response and
concentration of cOH was obtained with a 0.9911 correlation
coefficient (Fig. S15, ESI†). The probe 1 could selectively
detected cOH mainly because the lone pair electrons of PIII
atoms of triphenylphosphine moiety of the BODIPY uorophore
could be oxidized to triphenylphosphine oxide PV]O to form
the compound OX-1. In fact, this speculation has been
demonstrated by preparing independently the compound OX-1
using Fenton reaction as depicted in Scheme 1. By comparing
31P NMR spectroscopy of OX-1 and probe 1, the chemical shi of
phosphorus atoms were obviously different and was
ꢀ14.26 ppm and 32.00 ppm, respectively (Fig. S16, ESI†). These
results demonstrated that probe 1 could be used as a sensitive
turn-on uorescence sensor for detecting cOH with excellent
selectivity.
3,4-Dihydroxybenzaldehyde, 1-bromohexadecane, boron tri-
uoride diethyletherate (BF3$Et2O), triuoroacetic acid and 2-
(diphenylphosphino)benzaldehyde were purchased from J&K
Scientic Ltd. 2,4-Dimethyl-pyrrole was obtained from Nanjing
Chemlin Chemical Industry Co. Ltd. Sodium hypochlorite
(NaClO) and potassium dioxide (KO2), tert-butyl hydroperoxide
(TBHP) were supplied by Sigma Aldrich. Other chemicals or
solvents were purchased from Sinopharm Chemical Reagent
Co. Ltd, such as hydrogen peroxide (H2O2), ferric chloride
hexahydrate (FeCl3$6H2O), ferrous sulfateheptahydrate
(FeSO4$7H2O), N,N-dimethylformamide (DMF), dimethyl sulf-
oxide (DMSO), triethylamine (Et3N), dichloromethane (CH2Cl2),
et al. All chemicals and solvents were used directly without
further purication unless otherwise noted. All air and moisture
sensitive reactions were carried out under an argon
Fig. 4 Confocal fluorescence and bright field images of HeLa cells. (a)
Cells incubated with 10 mmol Lꢀ1 of probe 1 for 30 min at 37 ꢁC. (b)
Bright field image of cells showed in (a). (c) One overlay image of (a and
Fig. 3 Changes in the fluorescence spectrum of probe 1 (10 mmol Lꢀ1 b). (d) Cells incubated with 10 mmol Lꢀ1 probe 1 at 37 ꢁC for 30 min and
in DMSO) as the concentration of cOH is increased upon excitation at then treated with PMA for 1 h. (e) Bright field image of cells showed in
580 nm.
(d). (f) One overlay image of (d and e).
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atmosphere. Dry CH2Cl2 was obtained by reuxing and
distilling over CaH2 under nitrogen. Triethylamine was ob-
tained by simple distillation.
Nuclear magnetic resonance (NMR) spectra were obtained
from a Bruker 500 or 600 MHz spectrometer with TMS as an
internal standard operating for 1H, 13C NMR and 31P NMR.
Mass spectra were measured with a Bruker ultraex MALDI TOF
MS spectrometer. HRMS data were obtained on an Agilent 6224.
Synthesis of compound 2
In a 250 mL ask, a solution of compound 3 (1.17 g, 2 mmol) and
2,4-dimethylpyrrole (0.38 g, 4 mmol) in anhydrous CH2Cl2 (100
mL) was stirred under an atmosphere of argon for 10 min. Tri-
uoroacetic acid (0.01 mL) was added and the reaction mixture
was stirred at room temperature overnight. 2,3-Dichloro-5,6-
dicyano-1,4-benzoquinone (0.45 g, 2 mmol) was then added to
the above mixture and stirred at room temperature for 1 h. The
solution was cooled in an ice bath (0 ꢁC) and the triethylamine (3.0
mL) and excessive BF3$Et2O were added dropwise and the nal
mixture continually reacted at 0 ꢁC for 5 h. The reaction was then
quenched with water (30 mL) and the reaction mixture was worked
up by extraction with CH2Cl2 (3 ꢂ 30 mL). The organic extract was
dried by anhydrous Na2SO4, ltered, and rotary evaporated. The
residue was puried by column chromatography over silica gel
with a solvent mixture of petroleum ether/CH2Cl2 (v/v ¼ 1/2) as the
eluent to give compound 2 in 62.2% yield as a red solid. 1H NMR
(CDCl3, 600 MHz): 6.97 (d, J ¼ 6 Hz, 1H), 6.79–6.75 (m, 2H), 5.98 (s,
2H), 4.04 (t, J ¼ 6 Hz, 2H), 3.94 (t, J ¼ 6 Hz, 2H), 2.55 (s, 6H), 1.89–
1.83 (m, 2H), 1.82–1.78 (m, 2H), 1.48 (s, 6H), 1.47–1.36 (m, 4H),
1.34–1.22 (m, 48H), 0.88 (t, J ¼ 6 Hz, 6H). 13C NMR (CDCl3, 150
MHz) d (ppm): 155.25, 149.72, 149.59, 143.22, 141.88, 131.75,
127.10, 121.03, 120.39, 113.75, 113.29, 69.45, 69.22, 31.94, 29.73,
29.68, 29.65, 29.64, 29.63, 29.61, 29.50, 29.44, 29.38, 29.28, 29.22,
26.06, 25.97, 22.71, 14.58, 14.46, 14.14. HRMS (ESI): m/z calcd for
C51H84BF2N2O2: 805.65884 [M + H]+; found: 805.65775.
Procedures for ROS/RNS radicals sensing
Stock solutions of various ROS/RNS radicals (0.1 mol Lꢀ1), such
as H2O2, ClOꢀ, O2cꢀ, TBHP, NO, NO2ꢀ, Vc, Fe3+, GSH were
prepared in deionized water. Fenton reaction between FeCl3
and hydrogen peroxide was used to generate cOH. For selectivity
evaluation, probe 1 (3.0 mL, 10 mmol Lꢀ1, dimethyl sulfoxide
solution) was added to the quartz optical cell of 1 cm optical
path length, and then, adding appropriate amounts of the ROS/
RNS radicals sample. For titration, the cOH solution was grad-
ually added to probe 1 (3.0 mL, 10 mmol Lꢀ1, dimethyl sulfoxide
solution) using a micro-pipette. Fluorescence was measured for
580 nm excitation within 585–800 nm.
Cell culture and uorescence bioimaging
The HeLa cell line was provided by the Institute of Biochemistry
and Cell Biology, SIBS, CAS (China). Cells were grown in high
glucose Dulbecco's Modied Eagle Medium (DMEM, 4.5 g of
glucose per L) supplemented with 10% fetal bovine serum (FBS)
Synthesis of probe 1
ꢁ
at 37 C and 5% CO2. Cells (5 ꢂ 108 L) were plated on 14 mm
Compound 2 (0.08 g, 0.1 mmol) and 2-(diphenylphosphino)
benzaldehyde (0.11 g, 0.3 mmol) were added to a 100 mL two-
neck round bottomed ask containing a 60 mL mixed solvent
of acetonitrile and 1,2-dichloroethane (v/v ¼ 3/1), and to this
solution was piperidine (0.4 mL) and acetic acid (0.4 mL). The
mixture was heated at 90 ꢁC under Ar atmosphere by using
a Dean–Starktrap, and the reaction was monitored by TLC.
When compound 2 was completely consumed, the reaction
mixture was cooled to room temperature and solvent was
evaporated. Water (20 mL) was added to the residue and
extracted with CH2Cl2 (3 ꢂ 20 mL). The organic phase was dried
over anhydrous Na2SO4, ltered, and rotary evaporated. The
residue was puried by column chromatography over silica gel
with a solvent mixture of ethyl acetate/CHCl3 (v/v ¼ 1/3) as
glass cover slips and allowed to adhere for 24 h. Experiments to
assess cOH uptake were performed over 1 h in the same medium
supplemented with 10 mmol Lꢀ1 phorbol 12-myristate 13-
acetate (PMA). Immediately before the experiments, cells were
washed with PBS buffer and then incubated with 10 mmol Lꢀ1
probe 1 in PBS buffer for 30 min at 37 ꢁC. Cell imaging was then
carried out aer washing the cells with PBS buffer. Confocal
uorescence imaging was performed with a Zeiss LSM 710 laser
scanning microscope and a 63ꢂ oil-immersion objective lens.
Cells incubated with probe 1 were excited at 633 nm using
a multi-line argon laser.
Experiments
Synthesis of compound 3
1
eluent to give probe 1 in 7.4% yield as a black solid. H NMR
(500 MHz, CDCl3) d (ppm): 8.04 (s, 1H), 8.01 (s, 1H), 7.95 (q, J ¼
3,4-Dihydroxybenzaldehyde (1.38 g, 10 mmol), 1-bromohex- 5 Hz, 2H), 7.70–7.61 (m, 4H), 7.53 (t, J ¼ 5 Hz, 1H), 7.49–7.44 (m,
adecane (12.2 g, 40 mmol), potassium carbonate (4.14 g, 30 2H), 7.42 (t, J ¼ 5 Hz, 2H), 7.35–7.28 (m, 15H), 7.21 (t, J ¼ 5 Hz,
mmol), potassium iodide (0.10 g, 0.6 mmol) and DMF (50 mL) 2H), 6.95 (d, J ¼ 5 Hz, 1H), 6.89 (q, J ¼ 5 Hz, 2H), 6.77–6.73 (m,
were added to into a 100 mL ask, the mixture was then stirred 2H), 6.44 (s, 2H), 4.04 (t, J ¼ 5 Hz, 2H), 3.93 (t, J ¼ 5 Hz, 2H),
ꢁ
at 70 C for 14 h. Aer reaction completion, the mixture were 1.89–1.83 (m, 2H), 1.82–1.77 (m, 2H), 1.48 (s, 6H), 1.45–1.39 (m,
cooled to room temperature and poured into ice water (100 mL). 4H), 1.30–1.22 (m, 48H), 0.90–0.85 (m, 6H). 13C NMR (CDCl3,
Then, solid precipitation was lter and recrystallized with 125 MHz) d (ppm): 152.52, 149.61, 142.24, 140.91, 140.82,
a solvent mixture of chloroform and methanol to give gray solid 139.23, 136.43, 136.28, 136.21, 134.27, 134.03, 133.87, 133.72,
product 3 in 83.6% yield (4.9 g).34 1H NMR (CDCl3, 500 MHz) 133.63, 131.92, 129.22, 128.24, 128.64, 128.48, 127.51, 127.15,
d (ppm): 9.83 (s, 1H), 7.44–7.39 (m, 2H), 6.95 (d, J ¼ 10 Hz, 1H), 126.33, 120.75, 120.55, 117.99, 113.68, 113.60, 69.54, 69.23,
4.07 (q, J ¼ 5 Hz, 4H), 1.90–1.80 (m, 4H), 1.54–1.41 (m, 4H), 31.93, 29.72, 29.68, 29.64, 29.50, 29.44, 29.37, 29.28, 29.23,
1.40–1.16 (m, 48H), 0.88 (t, J ¼ 10 Hz, 6H).
26.06, 25.97, 22.69, 14.66, 14.57, 14.12. 31P NMR (202 MHz,
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CDCl3) d (ppm): ꢀ14.26; MALDI-TOF MS: m/z: calculated for
Notes and references
C
89H110BF2N2O2P2 [M + H]+: 1349.8098; found: 1349.3503.
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In a 100 mL round bottomed ask, a solution of probe 1 (0.02
mmol) and hydrogen peroxide (0.2 mmol) in tetrahydrofuran
(50 mL) were stirred at room temperature for 2 min. FeSO4-
$7H2O (0.12 mmol) was then added to this mixture. The nal
mixture was continually stirred at room temperature and ended
until the probe 1 was completely consumed (monitored by TLC).
Aer the solvent was evaporated, water (20 mL) was added to the
residue and extracted with CHCl3 (3 ꢂ 20 mL). The organic
phase was dried over anhydrous Na2SO4, ltered, and evapo-
rated to give compound OX-1 in quantitative yield as a black
˜
´
´
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1
solid. H NMR (500 MHz, CDCl3) d (ppm): 8.14 (s, 1H), 8.10 (s,
1H), 8.04 (q, J ¼ 5 Hz, 2H), 7.69–7.65 (m, 9H), 7.60–7.56 (m, 3H),
7.54–7.50 (m, 5H), 7.49–7.43 (m, 9H), 7.17 (q, J ¼ 5 Hz, 2H), 6.94
(d, J ¼ 5 Hz, 1H), 6.75–6.72 (m, 2H), 6.27 (s, 2H), 4.03 (t, J ¼ 5 Hz,
2H), 3.93 (t, J ¼ 5 Hz, 2H), 1.89–1.83 (m, 2H), 1.82–1.78 (m, 2H),
1.53–1.46 (m, 4H), 1.44 (s, 6H), 1.29–1.24 (m, 48H), 090–0.85 (m,
6H). 13C NMR (CDCl3, 125 MHz) d (ppm): 152.29, 149.73, 142.41,
141.34, 141.29, 139.70, 134.13, 134.11, 133.91, 133.83, 133.73,
133.27, 132.44, 132.31, 131.95, 131.00, 130.20, 128.69, 128.60,
127.66, 127.57, 127.02, 121.49, 120.12, 118.51, 113.77, 113.58,
69.52, 69.28, 31.94, 29.73, 29.50, 29.38, 29.29, 26.07, 26.00,
22.70, 14.58, 14.13. 14B NMR (160 MHz, CDCl3) d (ppm): 1.16;
31P NMR (202 MHz, CDCl3) d (ppm): 32.00; MALDI-TOF MS: m/z:
calculated for C89H108BFN2O4P2 [M ꢀ H ꢀ F]: 1360.8; found:
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1360.5. HRMS (ESI): m/z calcd for
C89H110BF2N2O4P2:
14 Y. Huang, A. Sinha, H. Zhao, X. Dang, Y. Zhang and X. Quan,
ChemistrySelect, 2019, 4, 12507–12511.
1381.79965 [M + H]+; found: 1381.80110.
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In summary, we have successfully designed and synthesis
a sensitive uorescent probe to monitor cOH in living cells. This
probe is designed based on BODIPY platform with two triphe-
nylphosphine groups as a reactive-site. The probe's turn-on
mechanism utilized an oxidation reaction of phosphorus
atom by cOH. We envision that this probe may be a useful tool
for investigation of physiological and pathological functions of
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Conflicts of interest
There are no conicts to declare.
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Acknowledgements
This research was supported by the Scientic and Technological
Innovation Programs of Higher Education Institutions in
Shanxi (No. 2019L0879 and No. 2019L0894), the Construction
Plan of “1331” engineering Photoelectric Material Innovation
Team of Jinzhong University (No. jzxycxtd2017007), and the
Shanxi “1331” project Key Innovative Research Team (No.
PY201817).
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