A novel fluorescent probe with high photostability for imaging distribution of RNA in living cells and tissues

Article abstract of DOI:10.1039/d0nj05286h

RNA has always been valued by scientists in the field of biomedicine, especially biochemistry. Exploring the action and distribution of RNA in the biological environment can help us to gain a deeper understanding of organisms. Although several RNA probes have been developed over the years, it is still necessary to develop more robust RNA probes. Herein, we firstly applied bithiophene to design the novel RNA probeBT-PHITby modifying 2,2′-bithiophene. The new probe can specifically recognize endogenous RNA in cells and tissues to produce a clear fluorescent image. Interestingly,BT-PHIThas better photostability and longer tissues imaging depths than traditional RNA probes. Additionally, the robust probe has a large stokes shift and fine membrane permeability.

Full text of DOI:10.1039/d0nj05286h

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A novel fluorescent probe with high photostability
for imaging distribution of RNA in living cells and
tissues†
Cite this: New J. Chem., 2021,
45, 2614
a
ab
Zhaomin Wang,a Yong Liu,
Weishan Wang,a Chang Zhaoa and Weiying Lin
*
RNA has always been valued by scientists in the field of biomedicine, especially biochemistry. Exploring
the action and distribution of RNA in the biological environment can help us to gain a deeper
understanding of organisms. Although several RNA probes have been developed over the years, it is still
necessary to develop more robust RNA probes. Herein, we firstly applied bithiophene to design the
novel RNA probe BT-PHIT by modifying 2,20-bithiophene. The new probe can specifically recognize
endogenous RNA in cells and tissues to produce a clear fluorescent image. Interestingly, BT-PHIT has
better photostability and longer tissues imaging depths than traditional RNA probes. Additionally, the
robust probe has a large stokes shift and fine membrane permeability.
Received 28th October 2020,
Accepted 17th December 2020
DOI: 10.1039/d0nj05286h
rsc.li/njc
functions and distribution. However, exploration of RNA requires
better tools, and so it is necessary to develop better RNA probes.
Introduction
Fluorescent probes are powerful tools and play an important
In recent years, some studies on RNA probes have been
role in many fields such as biological research, diagnosis and reported. For instance, Elhussin et al.23 synthesized an RNA
treatment of diseases.1,2 Due to the simplicity and sensitivity of probe based on quinine, which can target RNA in the second
fluorescent probes, various fluorescence imaging techniques near-infrared window with fluorescence enhancement. Yoshino
have been developed rapidly in recent years.3–8 Many traditional et al.24 successfully synthesized another low biological toxicity
dyes have been incorporated into fluorescent probes for fluo- RNA probe based on quinoline and applied the probe to image
rescence imaging to be used in various fields.9,10 Fluorescent endogenous RNA in the nucleoli of a living cell. In addition,
probes can image otherwise invisible structures in biological some RNA probes based on benzothiazole, indole and carbazole
environments and realize non-invasive visualization.11,12 In a have been synthesized.25 They each have different characteristics
sense, the development of fluorescent probes has promoted our and functions. However, few RNA probes have outstanding per-
understanding of biological science.13
Ribonucleic acid (RNA) is an extremely important carrier of with unpublished structures are not very good at photostability.
genetic material. It is distributed mainly in the nucleolus and Most of the RNA probes that are developed at present are
formance in photostability. Even commercialized RNA dyestuffs
cytoplasm of biological cells. RNA has an important role in many based on quinoline, indole and benzothiazole.23–27 The struc-
aspects of cell life activities.14 Since the discovery of RNA, protein tures of these hosts are likely to be the main reason affecting
coding has been considered as its main function.15–17 RNA is widely photobleaching tolerance. Therefore, we tried to use a novel
involved in gene regulation.18–20 RNA is not only a bridge between bithiophene structure as the matrix in the hope of developing
DNA and protein, involved in gene expression and signal trans- an RNA probe with high photostability. Bithiophene is a
mission, but also a catalyst in many specific reactions.21,22 Since compound similar to carbazole and has a wide range of optical
RNA was discovered, scientists have been exploring its nature, and electrochemical properties.28,29 In the field of RNA probes,
bithiophene has not been used as a substrate.
As we all know, RNA is a single stranded structure made up
of many bases, and these bases caused a groove structure.
When a probe intercalates with these grooves, the wavelength
or intensity of the emission fluorescence of the probe may
change.30,31 Therefore, RNA probes were usually designed in
light of this intercalation effect. It has been reported that small
molecular compounds with a V-conjugated structure can detect
RNA using the embedding mechanism.32
a Institute of Fluorescent Probes for Biological Imaging, School of Materials Science
and Engineering, School of Chemistry and Chemical Engineering, University of
Jinan, Jinan, Shandong 250022, P. R. China. E-mail: weiyinglin2013@163.com
b Guangxi Key Laboratory of Electrochemical Energy Materials, Institute of Optical
Materials and Chemical Biology, School of Chemistry and Chemical Engineering,
Guangxi University, Nanning, Guangxi 530004, P. R. China
† Electronic supplementary information (ESI) available: Experimental details
including synthesis, characterization of the compounds, absorption and fluores-
cence spectroscopic data, and living cell imaging. See DOI: 10.1039/d0nj05286h
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Scheme 1 The synthetic route of the probe BT-PHIT.
Cell culture and imaging
Composition of cell culture medium: the volume ratio of
DMEM (Dulbecco’s Modified Eagle’s Medium), fetal bovine
serum and penicillin was 100 : 10 : 1. Cells were cultured in
the CO2 constant temperature incubator. Cells were transferred
to confocal dishes 24 hours before imaging using a Nikon
AMP1 laser scanning confocal microscope. The cell coverage
rate reached about 70% before imaging of the cell. In the
experimental and control groups, the culture medium containing
probe BT-PHIT (10 mM) was used for 30 minutes before imaging,
and then PBS solution was used for cleaning. After cleaning, PBS
was removed and new culture medium was added for imaging.
Fig. 1 Sensing strategies of the probe BT-PHIT to RNA.
Based on this information, we synthesized an RNA probe
BT-PHIT with a novel structure by modifying bithiophene.
We connected pyridine with 2,20-bithiophene by a coupling
reaction and modified one end with iodoethane to form a
V-conjugated structure. BT-PHIT has fluorescence emission in
the range of 570–620 nm in the nucleolus and cytoplasm under
the excitation wavelength of 488 nm. First, we demonstrated
that the fluorescence emission of the probe was caused by
endogenous RNA in cells by enzymatic verification. Then,
we investigated the photostability of BT-PHIT by comparing
commercial probes. Finally, we tested the imaging depth of the
probe using mouse liver tissue. Interestingly, BT-PHIT has
a higher photostability than conventional probes and a deeper
imaging depth than commercial probes (Fig. 1).
RNase digestion test
After live cell imaging, an RNase digestion test was carried out,
according to the previous reports. First, two groups of cells with
70% cell coverage were cultured in confocal plates. The cells in
both groups were fixed with 1 mL 4% formalin-fixed solution
for 3 h. Then cells of both groups were pierced using 5% Triton
X-100 for 120 s and washed with PBS. Then, 1 mL PBS with 4 mL
RNase (5 mg mLꢀ1) was added to one group for 2 h. The control
group had a clean 1.004 mL of PBS added for the same time of
2 h. Finally, the two groups of cells were stained with BT-PHIT
and imaged.
Experimental
General procedure and spectral measurements
Tissue imaging
The biological tests were approved by the Institutional Animal
Care and Use Committee of Shandong University. All animal
procedures were performed in accordance with the Guidelines
for Care and Use of Laboratory Animals of Shandong University
and approved by the Animal Ethics Committee of Shandong
University. Liver tissue was taken from 7-week-old mice. Five-
week-old mice were bought from the School of Pharmaceutical
Sciences, Shandong University. They were fed for two weeks,
and liver tissue sections were taken for tissue imaging.
Preparation of samples: the probe BT-PHIT was made into a
1 mM solution with DMF. In the photophysical experiments,
the mother liquor was diluted to 5 mM with the solvent.
Preparation of test samples for detection: in the experiment
investigating the response of the probe BT-PHIT to RNA, the
test samples for detection were obtained by dissolving BaCl2,
CuSO4, FeCl3, K2CO3, MgCl2, NaNO3, and NH4Ac in deionized
water. RNA and DNA test solution were obtained by dissolving
RNA or DNA in Tris-buffer solution. By rough calculation, an
appropriate amount of RNA or DNA was weighed and dissolved
in Tris-buffer solution. The specific concentration was calcu-
lated using the Lambert–Beer formula and UV spectrum
Synthetic procedures
Synthesis routine of 1. Compound 5,50-dibromo-2,20-
measurement (for details, see the calculation method of RNA bithiophene (0.321 g, 1.0 mmol) was dissolved in DMF
and DNA concentration in the ESI†). (30 mL). K2CO3 (0.414 g, 3.0 mmol), palladium(II) acetate
Parameters for spectral measurements: the excitation wave- (0.022 g, 0.1 mmol) and tri(o-tolyl)phosphine (0.068 g,
length was 460 nm, the excitation slit width was 5 nm and the 0.2 mmol) were added. Then mixture was protected by N2 and
emission slit width was 5 nm.
heated to 313.15 K. 4-Vinyl pyridine (0.315 g, 3.0 mmol) was
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Table 1 The photophysical properties of BT-PHIT in various solvents
Solvents
la (nm)
lb (nm)
Fc
PBS
H2O
DMF
MeOH
MeCN
455
460
455
462
456
622
624
631
627
630
0.058
0.068
0.090
0.081
0.081
a
b
Fig. 3 Confocal fluorescence images of living HepG2 cells incubated with
Maximum absorption wavelength (nm). Maximum fluorescence
c
emission wavelength (nm). F is the fluorescence quantum yield (error BT-PHIT. Red fluorescence images were collected under excitation at
limit: 8%) determined by using rhodamine 6G (F = 0.95) in water as the
standard.
488 nm. Scale bar: 20 mm.
of the probe. As is known to all, when the probe is used for
detection, the larger the Stokes shift, the smaller the error. In
addition, the fluorescence quantum yield of the probe is about
8% in each system, and the corresponding quantum yield in
the organic system is relatively higher (Table 1 and Fig. 2,
quantum yields in the ESI†).
Then, in order to explore whether the probe can recognize
RNA in vitro, we carried out RNA titration in vitro. The probe
was dissolved in Tris–HCl buffer solution and maintained at a
specific concentration (1 mm), and the concentration of RNA in
the solution was increased during the measurement of fluo-
rescence spectrum. A graph of the change of probe fluorescence
intensity with RNA concentration was obtained (Fig. S1 in the
ESI†). Up to 700 equivalents of RNA, the fluorescence intensity
of the probe at 620 nm positively correlated with the change in
added using a syringe. The solution mixture was allowed to
reflux for 72 h at 393.15 K (Scheme 1).
Synthesis routine of BT-PHIT. 1 (0.534 g, 1.0 mmol) and
iodoethane (0.234 g, 1.5 mmol) were dissolved in absolute ethyl
alcohol (100 mL). The solution mixture was allowed to reflux
for 72 h at 353.15 K. 1H NMR (400 MHz, DMSO, d): 8.953
(d, J = 5.8 Hz, 2H; pyridine), 8.554 (d, J = 5.8 Hz, 2H; pyridine),
8.239 (d, J = 16.4 Hz, 1H; CHQCH), 8.210 (d, J = 6.8 Hz, 2H;
pyridine), 7.765 (d, J = 16.0 Hz, 1H; CHQCH), 7.552 (d, J = 6.0
Hz, 2H; pyridine), 7.525 (d, J = 4.0 Hz, 1H; thiophene), 7.502
(d, J = 5.2 Hz, 1H; thiophene), 7.483 (d, J = 3.6 Hz, 1H;
thiophene), 7.360 (d, J = 4.0 Hz, 1H; thiophene), 7.184
(d, J = 16.0 Hz, 1H; CHQCH), 7.6.982 (d, J = 16.0 Hz, 1H;
CHQCH), 4.531 (q, J = 7.2 Hz, 2H; CH2), 1.526 (t, J = 7.2 Hz, 3H;
CH3). 13C NMR, (400 MHz, DMSO-d) d (ppm): HRMS (m/z):
150.760, 150.525, 144.330, 144.134, 142.302, 140.188, 140.037,
136.406, 133.915, 133.823, 130.666, 126.882, 126.500, 126.393,
123.941, 123.941, 122.625, 121.188, 55.642, 21.562, 16.638. [M ꢀ I]+
+
calcd for C24H21N2S2 : 401.1141; found: 401.1141.
Results and discussion
Spectral measurements of BT-PHIT
Firstly, we measured the absorption spectrum and emission
spectrum of compound BT-PHIT. In several different solutions,
the absorption wavelength of the compound is concentrated in
the range of 455–460 nm. The strongest emission peak of the
probe BT-PHIT in DMF appears at 631 nm, and the strongest
emission peak in the water system appears at about 624 nm. It
is important that the compound exhibits a large Stokes shift
(about 160 nm) in both aqueous and organic solvent systems.
Stokes shift is a very important scale to measure the superiority
Fig. 4 RNase digest experiment. All fluorescence imaging pictures of
fixed cells stained with BT-PHIT (10 mM). Imaging picture of HeLa (A–C),
A549 (G–I), and HepG2 (M–O) cells not treated with RNase. Imaging
pictures of HeLa (D–F), A549 (J–L), and HepG2 (P–R) treated with RNase.
(S–U) Mean fluorescence intensity of the cytoplasm and nucleus before
and after treatment with RNase. lex = 488 nm, lem = 570–620 nm, and
bar = 20 mm.
Fig. 2 (A) Absorption spectra and (B) fluorescence responses of BT-PHIT
in various solvents; [BT-PHIT]: 5 mM.
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Fig. 5 Comparison of photobleaching of BT-PHIT and SYTO RNA-Select in confocal fluorescence microscopy imaging. (A) Image of living HeLa cells
incubated with BT-PHIT. (B) Image of living HeLa cells incubated with SYTO RNA-Select. (C) Change of normalized mean fluorescence intensity of
BT-PHIT and SYTO RNA-Select with time. [BT-PHIT]: 10 mM, [SYTP RNA-select]: 10 mM, lex = 488 nm, bar = 20 mm.
RNA concentration. When the RNA concentration increased speculated that BT-PHIT can mark endogenous RNA of living cells.
700-fold, the fluorescence intensity stabilized at about two So, we used the probe for imaging living cells.
times the original intensity. According to the experimental
First, we measured the biological toxicity of probe BT-PHIT
results, a change in fluorescence intensity at 630 nm was to cells using the standard 3-(4,5-dimethyl-2-thiazoly)-2,5-
selected to draw a scatter plot so as to study the detection limit diphenyl-2-H-tetrazolium bromide (MTT) assays prior to the
of the probe using the regression equation. The results show imaging. The results of the toxicity test showed that the probe
that the probe has an above average sensitivity (Fig. S2 in the has relatively low toxicity to cells (Fig. S7 in the ESI†). Then, we
ESI†).
cultured the cells with BT-PHIT and imaged them using a laser
Furthermore, various analytes including anions, cations, confocal microscope. As was expected, at lex = 488 nm, a clear
reducing agents, active oxides and common amino acids were fluorescence signal was observed in the red channel. According
used to test the probe BT-PHIT in Tris–HCl buffer solution and to the image, the area of fluorescence signal mainly appears in
the results were compared with those of RNA to further test the the nucleus and cytoplasm (Fig. 3). Therefore, we speculate that
ion selectivity of BT-PHIT (Fig. S3 in the ESI†). The analytes of the fluorescence signal may be caused by endogenous RNA of
the cations including Ca2+, Cu2+, Fe3+, K+, Mg2+, Na+, Ni+, and living cells.
Zn+, anions including Brꢀ, Clꢀ, Iꢀꢀ, NO3ꢀ, and SO42ꢀ, reducing
agents SO32ꢀ, active oxides NO2 and amino acids L-cysteine
(Cys) elicited no marked response. However, RNA with the same
The RNase digest experiment
Based on our conjecture, we carried out the digest test using
RNase (ribonuclease). We cultured three kinds of cancer cells
(HeLa, A549, and HepG2) in a constant temperature incubator.
Each kind of cell was divided into two groups. The other
conditions were the same after fixing and drilling. The only
variable was whether RNase was added. Then experimental
groups and control groups were imaged using a confocal laser
scanning microscope at 488 nm. Images of six groups of fixing
cells were obtained. Then, the mean fluorescence intensity of
different positions was counted using ImageJ software, and the
histogram was plotted (Fig. 4).
In the test group and blank control group of the three kinds
of cells, the probe BT-PHIT produced clear fluorescence images
in the red channel. In the control group of HeLa cells, the
red fluorescence appeared in the cytoplasm and nucleus
(Fig. 4A–C). In the RNase digested group, the fluorescence
disappeared in the cytoplasm, and strong fluorescence was
shown in the nucleus (Fig. 4D–F). As shown in Fig. 4S, the cells
without RNase digestion showed fluorescence signals distributing in
the nucleus and cytoplasm, and the average fluorescence intensity in
concentration as other ions except Cys could double the
fluorescence intensity of the probe at the same excitation
wavelength. The influence of DNA is almost inevitable for
RNA probes that are based on an embedding mechanism.
Therefore, we focus on the influence of DNA on detection. By
testing, RNA and DNA caused a red-shift of probe absorption in
buffer solution. However, the same concentration of RNA made
the probe have a longer red-shift than DNA (Fig. S4 in the ESI†).
We carried out titration experiments with RNA and DNA,
respectively, at lex = 488 nm. The results showed that the
fluorescence intensity of the probe in buffer solution with
RNA was higher than that with the same concentration of
DNA (Fig. S5 in the ESI†). In order to test the stability of the
probe in buffer solution, three groups of stability tests were
carried out. The results showed that the probe has high stability
whether it exists alone or with DNA and RNA (Fig. S6 in the
ESI†).
Imaging of endogenous RNA in living cells
The above experiment proved that probe BT-PHIT could specifically the cytoplasm was higher than that in the nucleus. After digestion by
check RNA in vitro. Moreover, water-soluble small molecules easily RNase, the fluorescence intensity in the cytoplasm was almost zero,
enter the cell through the pores on the membrane. We therefore and the average fluorescence intensity in the nucleus increased
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intuitively, we plotted the average fluorescence intensity of different
regions into a column graph (Fig. 4T and U). Experiments of several
groups had proved that the fluorescence signal of BT-PHIT is caused
by endogenous RNA of living cells.
Optical stability of BT-PHIT
Photostability is an important factor to evaluate the quality of
the probe.33,34 Therefore, we conducted experiments to test
the photostability of BT-PHIT. Culture medium with BT-PHIT
(10 mM) was used to produce HeLa cells and the cells in the
imaging dish were continuously scanned for 5 min using a
confocal microscope after being washed with PBS. As shown in
Fig. 5A, there was almost no change in the fluorescence image
of BT-PHIT within 5 minutes. In order to make the experi-
mental results more intuitive, we used commercial probe SYTO
RNA-Select replacing the probe BT-PHIT to image under the
same conditions, and compared the two probes. As shown in
Fig. 5B, the fluorescence signal of SYTO RNA-Select was
obviously quenched by light in the living cells. In contrast,
BT-PHIT had better photostability than the commercial probe
(Fig. 5C).
Imaging of tissue of mice
In order to further explore the application of the probe BT-PHIT, we
conducted a tissue imaging experiment using mice liver tissue. The
liver tissue of mice was taken out and sliced. Then the tissue
sections were incubated in PBS with BT-PHIT (10 mM) for 2 h. Then
the liver tissue section of mice was put in an imaging dish and
imaged using 488 nm excitation wavelength. We found that probe
BT-PHIT could show a fluorescence signal in the cytoplasm and
nucleus of mouse tissue cells (Fig. 6A). And the fluorescence signal
of probe BT-PHIT in the cytoplasm was found to be slightly stronger
than that in the nucleus. This is consistent with the previous results
in living cells. So, we infer that the fluorescence signal was caused by
endogenous RNA of mouse tissue cells.
Furthermore, the tissue imaging depth of BT-PHIT was
tested using a tomoscan experiment. We obtained three-
dimensional fluorescence images using a 488 nm excitation
wavelength microscope, (Fig. 6B). We found that the probe can
be used for the fluorescence imaging of mouse liver tissue with
about 50 mm depth (Fig. 6C). A commercial probe was used
for comparison. Mice tissue was incubated in PBS with SYTO
RNA-Select under the same conditions, and the tomoscan
experiment was performed. The results show that the imaging
depth of SYTO was about 25 mm (Fig. 6D). Therefore, we can
conclude that the imaging depth of the probe BT-PHIT is
Fig. 6 (A) Confocal fluorescence images of mouse tissue incubated with
BT-PHIT (10 mM); (B) 3D fluorescence images. Red channel (lex = 488 nm,
lem = 570–620 nm); (C) tissue fluorescence imaging of BT-PHIT at excellent.
different depths; (D) tissue fluorescence imaging of SYTO RNA-Select at
different depths.
Conclusion
slightly. In the other two groups of cancer cells (HepG2 and A549), To sum up, we synthesized a novel RNA probe BT-PHIT by
the fluorescence signal of the control group and experimental group decorating bithiophene. BT-PHIT has several favorable
is also significantly different. The fluorescence signal in the cyto- features, such as larger stokes shift, small biological toxicity,
plasm of the experimental group is much lower than that of the great membrane permeability and long tissue imaging depth.
control group (Fig. 4M–R). In order to reflect this difference more More interestingly, BT-PHIT has better photostability than the
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14 R. E. Johnston and H. R. Bose, Proc. Natl. Acad. Sci. U. S. A.,
1972, 69, 1514–1516.
15 Y. Ota, A. Kikuchi and M. Cashel, Proc. Natl. Acad. Sci.
U. S. A., 1979, 76, 5799–5801.
conventional probes. In addition, this is the first time that
bithiophene has been used in the field of RNA probes, and this
may provide a new strategy for the development of RNA probes.
16 L. C. Gerstenfeld, S. D. Chipman, C. M. Kelly, K. J. Hodgens,
D. D. Lee and W. J. Landis, J. Cell Biol., 1988, 106,
979–989.
17 S. Yamashita and S. Melmed, J. Clin. Invest., 1986, 78,
1008–1014.
Conflicts of interest
There are no conflicts to declare.
18 P. A. Sharp, Cell, 2010, 136, 577–580.
Acknowledgements
19 F. Michelini, A. P. Jalihal, S. Francia, C. Meers, Z. T. Neeb,
F. Rossiello, U. Gioia, J. Aguado, C. J. Weinert, B. Luke, G.
Biamonti, M. Nowacki, F. Storici, P. Carninci, N. G.
Walter and F. D. D. Fagagna, Chem. Rev., 2018, 118,
4365–4403.
20 A. Bastide and A. David, Biomolecules, 2018, 8, 100.
21 K. Kruger, P. J. Grabowski, A. J. Zaug, J. Sands,
D. E. Gottschling and T. R. Cech, Cell, 1982, 31, 147.
22 S. Brenner, F. Jacob and M. Meselson, Nature, 1961, 190,
576–581.
This work was financially supported by NSFC (21672083,
51503077, 21877048, 51973082, 22077048), Taishan Scholar
Foundation (TS 201511041), the startup fund of the University
of Jinan (309-10004), Doctor start up fund of University of Jinan
(160082102) and NSFSP (ZR2015PE001).
Notes and references
1 G. M. van Dam, G. Themelis, L. M. A. Crane, N. J. Harlaar,
R. G. Pleijhuis, W. Kelder, A. Sarantopoulos, J. S. de Jong, 23 I. E. H. Elhussin, S. Zhang, J. Liu, D. li, Q. Zhang, S. Li,
H. J. G. Arts, A. G. J. van der Zee, J. Bart, P. S. Low and
X. Tian, J. Wu and Y. Tian, Chem. Commun., 2020, 56,
V. Ntziachristos, Nat. Med., 2011, 17, 1315–1319.
1859–1862.
2 H. Kobayashi and P. L. Choyke, Acc. Chem. Res., 2010, 44, 83–90. 24 Y. Yoshino, Y. Sato and S. Nishizawa, Anal. Chem., 2019, 91,
3 L. Yuan, W. Lin, L. Tan, K. Zheng and W. Huang,
Angew. Chem., Int. Ed., 2013, 52, 1628–1630.
4 L. He, X. Yang, K. Xu, X. Kong and W. Lin, Chem. Sci., 2017,
8, 6257–6265.
5 Y. Tang, X. Kong, Z. Liu, A. Xu and W. Lin, Anal. Chem.,
2016, 88, 9359–9363.
6 P. Ning, W. Wang, M. Chen, Y. Feng and X. Meng, Chin.
Chem. Lett., 2017, 28, 1943–1951.
7 W. Xu, Z. Zeng, J. Jiang, Y. Chang and L. Yuan,
Angew. Chem., Int. Ed., 2016, 55, 13658–13699.
14254–14260.
25 Y. Ma, J. Yin, G. Li, W. Gao and W. Lin, Coord. Chem. Rev.,
2020, 406, 213144.
26 Y. Yoshino, Y. Sato and S. Nishizawa, Anal. Chem., 2019, 91,
14254–14260.
27 T. Chiba, T. Sato, Y. Sato and S. Nishizawa, Org. Biomol.
Chem., 2017, 15, 7765–7769.
28 B. Czaplinska, A. Maron, J. G. Malecki, G. S. Gorol, M.
Matussek, K. Malarz, A. M. Wilczkiewicz, W. Danikiewicz,
R. Musiol and A. Slodek, Dyes Pigm., 2017, 114, 119–132.
8 H. Zhu, J. Fan, J. Du and X. Peng, Acc. Chem. Res., 2016, 49, 29 T. Nakanishi, Y. Shiral and L. Han, J. Mater. Chem. A, 2015,
2115–2126.
3, 4229–4238.
9 X. H. Gao, Y. Y. Cui, R. M. Levenson, L. W. K. Chung and 30 S. Halder and D. Bhattacharyya, Prog. Biophys. Mol. Biol.,
S. M. Nie, Nat. Biotechnol., 2004, 22, 969–976. 2013, 113, 264.
10 M. J. Rust, M. Bates and X. Zhuang, Nat. Methods, 2006, 3, 31 Q. Yao, H. Li, L. Xian, F. Xu, J. Xia, J. Fan, J. Du, J. Wang and
793–795. X. Peng, Biomaterials, 2018, 177, 78.
11 W. Shu, S. Zang, C. Wang, M. Gao, J. Jing and X. Zhang, 32 G. Song, F. Miao, Y. Sun, X. Yu, J. Z. Sun and W. Y. Wong,
Anal. Chem., 2020, 92, 9982–9988. Sens. Actuators, B, 2012, 173, 329.
12 W. Shu, Y. Wu, S. Zang, S. Su, H. Kang, J. Jing and X. Zhang, 33 H. K. Kleinman, D. Philp and M. P. Hoffman, Curr. Opin.
Sens. Actuators, B, 2020, 303, 127284.
Biotechnol., 2003, 14, 526–532.
13 M. R. Gill, J. Garcia-Lara, S. J. Foster, C. Smythe, G. Battaglia 34 F. Pampaloni, E. G. Reynaud and E. H. K. Stelzer, Nat. Rev.
and J. A. Thomas, Nat. Chem., 2009, 1, 662–667. Mol. Cell Biol., 2007, 8, 839–845.
This journal is ©The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2021
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