Next Article in Journal
Enhanced Electrochemical Glucose Sensing via AuNP-Assisted Electrodeposition and Yeast Modification
Previous Article in Journal
From Natural Pigments to Bioinspired Sensors: The Emerging Role of Melanins
Previous Article in Special Issue
Development of Polyphenol–Metal Film-Modified Colored Porous Microspheres for Enhanced Monkeypox Antigen Detection
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Chemosensors
Volume 14
Issue 3
10.3390/chemosensors14030067
chemosensors-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Communication

A New Acridine-Based Fluorescent Sensor for the Detection of CN−

by
Yiyuan Zhang
1,
Chen Zhou
1,*,
Jiaxin Li
1 and
Evgeny Kovtunets
2,*
1
School of Chemistry & Environmental Engineering, Jilin Provincial International Joint Research Center of Photo Functional Materials and Chemistry, Changchun University of Science and Technology, Changchun 130022, China
2
Institute of Natural Sciences, Buryat State University, 671207 Buryat, Russia
*
Authors to whom correspondence should be addressed.
Chemosensors 2026, 14(3), 67; https://doi.org/10.3390/chemosensors14030067
Submission received: 13 February 2026 / Revised: 7 March 2026 / Accepted: 12 March 2026 / Published: 12 March 2026
(This article belongs to the Special Issue Application of Luminescent Materials for Sensing, 2nd Edition)
Browse Figures
Versions Notes

Abstract

A novel acridine-based fluorescent sensor (Sensor ANT) for the highly selective and sensitive detection of cyanide ions (CN−) was rationally designed and synthesized via the conjugation reaction of acridine-9-amine with 3-nitrophenyl isothiocyanate. The sensing mechanism is triggered by the specific interaction between exogenous CN− and the hydrogen-bonding moieties within the sensor’s molecular framework, which induces a distinct fluorescence quenching response. Systematic titration experiments confirmed that Sensor ANT exhibits rapid response kinetics, excellent selectivity, and reliable qualitative/quantitative detection capabilities toward CN−. Complementary biocompatibility assays, including in vitro cellular imaging and in vivo zebrafish experiments, further verified the promising application potential of this sensor in practical and biological detection scenarios. The detection limit (DL) of Sensor ANT for CN− was calculated to be 2.89 × 10−7 M, with a 1:1 binding stoichiometry and a binding constant of 1.95 × 104 M−1. These findings demonstrate that Sensor ANT represents a robust candidate for CN− detection in environmental and biological systems.

1. Introduction

Cyanide (CN−) is a highly toxic anion with a ubiquitous distribution in nature, being endogenously secreted by fungi and algae and naturally present in various foods and fruits [1,2]. While the toxic effects of natural cyanide on humans are generally negligible due to its extremely low concentration in natural matrices, the intensification of industrialization has led to the substantial discharge of cyanide-containing wastewater from metallurgical processes and fiber manufacturing. This has resulted in escalating environmental cyanide contamination, posing an increasingly severe threat to human health [3,4]. CN− can enter the human body through multiple routes, including percutaneous absorption, respiratory inhalation, and oral ingestion. Once internalized, CN− binds strongly to the ferric iron (Fe3+) center of cytochrome c oxidase, inhibiting its reduction to ferrous iron (Fe2+) and disrupting the mitochondrial electron transport chain. This impairment of cellular respiration induces severe damage to the central nervous system—an organ highly vulnerable to hypoxia—with clinical manifestations including nausea, coma, and even respiratory arrest [5,6,7]. Notably, the lethal dose of cyanide for humans ranges from merely 0.5 to 3.5 mg per kilogram of body weight [8,9,10,11], underscoring the urgent need for the development of facile, rapid, and sensitive analytical methods for CN− detection in diverse research and practical scenarios.
Fluorescent sensors have emerged as a powerful tool for CN− detection, gaining extensive attention due to their superior sensitivity, excellent selectivity, and rapid response kinetics [12,13,14,15,16]. In recent years, significant progress has been made in the design and fabrication of CN−-responsive fluorescent sensors, with four primary sensing mechanisms being widely exploited. (1) Hydrogen bond-mediated sensing: These sensors typically exhibit rapid responses to CN− but suffer from high susceptibility to environmental pH fluctuations and interference from other basic anions (e.g., F−) [17,18,19,20]. (2) Deprotonation-based sensing: Sensors relying on deprotonation mechanisms also feature short response times and generally demonstrate enhanced selectivity compared to hydrogen bond-mediated counterparts [21]. (3) Metal coordination-based sensing: Constructed via coordination interactions between fluorophores and metal ions, these sensors offer structural diversity and tunability through the modulation of spatial configuration and coordination modes. A key advantage is their favorable water solubility, facilitating applications in aqueous systems; however, their development is constrained by complex synthesis, limited stability, potential toxicity of metal complexes, and challenges in optimizing coordination affinity [22,23,24,25,26]. (4) Nucleophilic addition reaction-based sensing: Leveraging the strong nucleophilicity of CN− to trigger specific addition reactions with electron-deficient moieties on fluorophores, this class of sensors yields remarkable spectral changes. Subdivided based on reactive sites (e.g., C=C, C=O, C=N double bonds), these sensors are highly regarded for their excellent selectivity, high sensitivity, and facile synthesis, making them the most rapidly advancing category of CN− fluorescent sensors. Nevertheless, challenges such as relatively slow response kinetics persist, driving continuous research efforts to optimize their performance [27,28,29,30,31,32,33,34,35]. The current research trend of cyanide ion sensors has increasingly shifted towards combining with various materials such as nanomaterials, chemical dosimeters, and metal–organic frameworks, and has made certain progress [36,37].
Acridine and its derivatives represent a class of privileged fluorophores that have garnered substantial attention in the design of fluorescent sensors for environmental and biological target detection. Endowed with a rigid planar tricyclic aromatic structure, acridine-based fluorophores exhibit exceptional photophysical properties, including high molar extinction coefficients, strong fluorescence quantum yields, and excellent photostability. Moreover, the electron-rich aromatic ring of acridine allows for facile structural modification at multiple active sites (e.g., the 9-position of the acridine core), enabling the rational integration of recognition moieties and fine-tuning of photophysical behaviors. In the realm of ion and molecule sensing, acridine-based fluorescent sensors capitalize on diverse response mechanisms, such as intramolecular charge transfer (ICT), photoinduced electron transfer (PET), fluorescence resonance energy transfer (FRET), and aggregation-induced emission (AIE) [38,39,40,41]. For instance, the introduction of ion-specific recognition groups onto the acridine scaffold can trigger pronounced spectral shifts or fluorescence intensity changes upon target binding, realizing the sensitive and selective detection of analytes. Notably, acridine derivatives often display environmentally sensitive fluorescence, facilitating their application in aqueous media and biological systems—an essential advantage for practical sensing scenarios [42]. Due to these merits, acridine-based fluorescent sensors have been extensively explored for the detection of metal ions (e.g., Cu2+, Hg2+, Fe3+), anions (e.g., CN−, F−, PO43−), and small biomolecules, demonstrating great potential in environmental monitoring, food safety assessment, and clinical diagnostics. Meta-nitrophenol is a commonly used responsive group and electronic tuning unit in the design of fluorescent sensors. It possesses multiple advantages in sensing performance, molecular design, and application adaptability. It can precisely tune the molecular HOMO-LUMO energy levels, regulate the fluorescence emission wavelength, quantum yield, Stokes shift, and reduce background interference. Additionally, it provides a rigid plane that can easily integrate with conjugated systems such as acridine and indolinium, enhancing fluorescence stability and intensity. Therefore, combining m-nitrophenol with acridine to design a novel fluorescent sensor is highly attractive.
In this work, a novel acridine-derived fluorescent sensor (Sensor ANT) for CN− detection was rationally designed and synthesized. The sensing mechanism was based on CN−-induced disruption of intramolecular hydrogen-bonding interactions within the sensor framework, triggering a distinct fluorescence quenching response. Benefiting from its excellent selectivity, high sensitivity, rapid response kinetics, and favorable biocompatibility, Sensor ANT exhibits superior practical applicability compared with conventional sensors of the same category.

2. Materials and Methods

2.1. Materials and Reagents

All chemicals and reagents employed in this work were purchased from Aladdin Reagent Co., Ltd. (Shanghai, China) and used as received without additional purification. Solvents for spectroscopic measurements were of high-performance liquid chromatography (HPLC) grade with no detectable fluorescent impurities. Stock solutions of target anions (NO3−, BrO3−, H2PO4−, HPO42−, C2O42−, CrO42−, F−, CN−, I−, ClO4−, SO42−, S2O32−, PO43−, HCO3−, NO2−, CO32−, HSO3−, N3−, and Na2S) and cations (Al3+, Zn2+, Pb2+, Mn2+, Mg2+, Hg2+, Fe3+, Ca2+, Cu2+, Cd2+, Ba2+) for the titration experiments were prepared from their respective salts (Aladdin Reagent Co., Ltd., Shanghai, China). Prior to use, all ion stock solutions were dissolved in 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES)-NaOH buffer solution (pH 7.4).

2.2. Instrumentation

The synthetic fluorescent sensor was characterized via nuclear magnetic resonance (1H NMR, 13C NMR) spectroscopy and high-resolution mass spectrometry (HRMS). 1H NMR and 13C NMR spectra were recorded on a Varian Mercury-300 spectrometer (Varian, Palo Alto, CA, USA) using dimethyl sulfoxide (DMSO-d6) as the solvent and tetramethylsilane (TMS) as the internal standard. HRMS data were acquired using an Agilent 1290-micro TOF QII system (Agilent, Santa Clara, CA, USA). Full characterization details, including corresponding spectra, are available in the Supplementary Materials (Figures S1–S4). Ultraviolet–visible (UV–Vis) absorption spectra were measured on a Shimadzu UV-2600 spectrophotometer (Shimadzu, Kyoto, Japan) using a 1 cm-pathlength quartz cuvette, with the scanning wavelength range set at 370–575 nm. Fluorescence emission spectra were collected with a Hitachi F-4500 spectrofluorimeter (Hitachi, Tokyo, Japan) in a 1 cm quartz cell over the wavelength range of 400–550 nm; both excitation and emission slit widths were fixed at 5 nm. Solution pH values were measured using a Mettler–Toledo DELTA 320 pH meter (Mettler–Toledo, Parramatta, NSW, Australia). Fluorescence cell imaging experiments were conducted on an Olympus IX-70 fluorescence microscope coupled with an Olympus C-5050 digital camera (Olympus, Tokyo, Japan).

2.3. Synthesis of Sensor ANT

Acridine-9-amine (2.2 mg, 0.01 mmol) and 3-nitrophenyl isothiocyanate (2.4 mg, 0.01 mmol) were dissolved in 20 mL of tetrahydrofuran (THF). The resulting mixture was refluxed at 70 °C for 6 h under a nitrogen atmosphere. Upon completion of the reaction (monitored by thin-layer chromatography), the mixture was cooled to room temperature, and the solvent was removed under reduced pressure using a rotary evaporator (Yuxiang, Gongyi, China). The crude product was purified by silica gel column chromatography using a mixed eluent of petroleum ether/ethyl acetate (v/v = 1:1), affording a pale-yellow solid product, designated as 1-(acridin-9-yl)-3-(3-nitrophenyl)thiourea (Sensor ANT), with a yield of 86%. The synthetic route for Sensor ANT is depicted in Scheme 1. 1H NMR (300 MHz, DMSO-d6, 25 °C) δ: 11.95 (s, 1H, NH), 11.63 (s, 1H, NH), 8.21 (m, 2H, Ar-H), 8.10 (m, 1H, Ar-H), 8.08 (m, 1H, Ar-H), 7.67 (m, 2H, Ar-H), 7.52 (m, 3H, Ar-H), 7.32 (m, 3H, Ar-H). 13C NMR (75 MHz, DMSO-d6, 25 °C) δ: 180.02, 164.94, 145.96, 143.02, 131.22, 130.70, 128.42, 128.01, 127.58, 123.98, 123.30, 122.26, 116.52, 115.49. ESI-MS m/z [M]+ calcd. for C20H14N4O2S: 374.4; obsd.: 374.1 (Figures S1–S3).

2.4. UV–Vis and Fluorescence Spectroscopic Measurements

All UV–Vis and fluorescence spectroscopic measurements were conducted at 25 °C. For selectivity experiments, the Sensor ANT stock solution (5 × 10−4 mol/L in ethanol) was diluted to a final concentration of 5 × 10−4 mol/L in a mixed solvent system of ethanol/HEPES-NaOH buffer (v/v = 1:1, pH 7.4). Equivalent volumes (2 mL) of aqueous solutions containing different anions or cations (5 × 10−4 mol/L) were individually added to the sensor solution, and UV–Vis absorption spectra (370–575 nm) and fluorescence emission spectra (400–550 nm) were recorded with an excitation wavelength (λex) of 390 nm.
For the titration experiments, the Sensor ANT stock solution was diluted to 5 × 10−4 mol/L in ethanol/HEPES-NaOH buffer (v/v = 1:1, pH 7.4). Gradient concentrations of CN− solution (5 × 10−5–5 × 10−4 mol/L) were sequentially added to the sensor solution, and fluorescence emission spectra were recorded after each addition (λex = 390 nm, λem = 426 nm). The detection limit was calculated using the equation: DL = K × Sb1/S, where K = 2 (confidence factor), Sb1 is the standard deviation of the fluorescence response of the blank solution, and S is the slope of the linear calibration curve [43].
For competitive experiments, CN− (5 × 10−4 mol/L) was first added to the Sensor ANT solution (5 × 10−4 mol/L) to achieve complete fluorescence quenching. Subsequently, interfering ions (5 × 10−3 mol/L, 10-fold excess) were added to the pre-quenched ANT-CN− system, and fluorescence intensities at 426 nm were recorded.
The binding constant and stoichiometric ratio were determined via the Stern–Volmer equation: I0/I = 1 + Ksv [Q], where I0 and I are the fluorescence intensities in the absence and presence of CN− (quencher, Q), respectively, Ksv is the Stern–Volmer quenching constant, and [Q] is the concentration of CN− [44].

2.5. Response Time Measurement

The response kinetics of Sensor ANT toward CN− were investigated in ethanol/HEPES-NaOH buffer (v/v = 1:1, pH 7.4) at 25 °C. Sensor ANT and CN− were both at a final concentration of 10 μM. The fluorescence intensity at 426 nm (λex = 390 nm) was recorded at regular time intervals (0–5 min) after the addition of CN−.

2.6. Cytotoxicity Assay

The cytotoxicity of Sensor ANT against HL-7702 normal liver cells was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. HL-7702 cells were seeded in 96-well plates at a density of 5 × 103 cells per well and incubated at 37 °C under a 5% CO2 atmosphere for 24 h. The cells were then treated with different concentrations of Sensor ANT (0.1, 0.5, 1.0, 5.0, 10.0, 50.0, 100.0 μM) and incubated for another 24 h. After removing the culture medium, 20 μL of MTT solution (5 mg/mL in PBS) was added to each well, and the cells were incubated for 4 h. The MTT-formazan crystals were dissolved in 150 μL of DMSO, and the absorbance at 490 nm was measured using a microplate reader (Bio-Rad, Hercules, CA, USA). Cell viability was calculated as (Absorbance of treated group/Absorbance of control group) × 100%. The half-maximal inhibitory concentration (IC50) was calculated using GraphPad Prism 8 software [45].

2.7. Cellular and Zebrafish Imaging Experiments

For cellular imaging: HL-7702 cells were seeded on glass coverslips in 6-well plates and incubated at 37 °C under a 5% CO2 atmosphere for 24 h. The cells were incubated with Sensor ANT (20 μM) for 30 min, rinsed three times with PBS (pH 7.4) to remove excess sensor, and then treated with CN− (20 μM) for another 30 min. Bright-field and fluorescence images were captured using an Olympus IX-70 fluorescence microscope.
For zebrafish imaging: Adult zebrafish were maintained in standard aquarium water at 28 °C with a 14 h light/10 h dark cycle. Zebrafish were first incubated with Sensor ANT (10 μM, dissolved in DMSO, final DMSO concentration < 0.1%) for 20 min, rinsed three times with PBS (pH 7.4) to remove unbound sensor, and then exposed to CN− (10 μM) for 1 h. Fluorescence images were captured under UV light (365 nm) using an Olympus C-5050 digital camera.

3. Results

3.1. UV–Vis Spectral Response of Sensor ANT

Titration experiments were performed to investigate the UV–Vis spectral responses of Sensor ANT upon exposure to various ions. As illustrated in Figure 1, Sensor ANT exhibited a characteristic maximum absorption peak at 390 nm in the ethanol/HEPES-NaOH buffer system (v/v = 1:1, pH 7.4). Notably, the addition of any tested ions (anions: NO3−, BrO3−, H2PO4−, HPO42−, C2O42−, CrO42−, F−, CN−, I−, ClO4−, SO42−, S2O32−, PO43−, HCO3−, NO2−, CO32−, HSO3−, N3−, and Na2S; cations: Al3+, Zn2+, Pb2+, Mn2+, Mg2+, Hg2+, Fe3+, Ca2+, Cu2+, Cd2+, Ba2+) did not induce significant changes in the UV–Vis absorption spectrum of Sensor ANT. However, the introduction of CN− causes a significant red shift in the UV spectrum of Sensor ANT, resulting in a new absorption peak at 489 nm. At the same time, the solution color changes from colorless to yellow, allowing Sensor ANT to recognize CN− with the naked eye. However, the absorbance of this new absorption peak is less than that at 390 nm, so 390 nm was selected as the maximum excitation wavelength for the subsequent fluorescence emission spectrum.

3.2. Fluorescence Sensitivity and Quantitative Detection of CN−

To evaluate the sensing sensitivity of Sensor ANT toward CN−, variations in its fluorescence spectra were systematically investigated upon exposure to gradient concentrations of CN−. As depicted in Figure 2, the fluorescence intensity of Sensor ANT at the characteristic emission peak of 426 nm (λex = 390 nm) exhibited a gradual and significant decrease with increasing CN− concentration. This CN−-induced fluorescence quenching phenomenon was visually distinguishable under UV irradiation. A good linear relationship between the fluorescence intensity at 426 nm and the CN− concentration was observed over the range of 0.1–1 equivalent (R2 = 0.9988), demonstrating the potential of Sensor ANT for quantitative CN− detection. Based on the detection limit calculation equation, the DL of Sensor ANT for CN− was determined to be 2.89 × 10−7 M. A comparative analysis with previously reported organic fluorescent sensors for CN− detection revealed that Sensor ANT exhibited a competitive detection performance, highlighting its potential applicability in practical cyanide sensing scenarios.

3.3. Selectivity and Anti-Interference Capability

Selectivity is a pivotal benchmark for evaluating the performance of fluorescent sensors. To validate the selectivity of Sensor ANT toward CN−, fluorescence measurements were conducted in the presence of various common ions. As depicted in Figure 3 (orange bars), only the addition of CN− induced a pronounced quenching effect on the fluorescence intensity of Sensor ANT, whereas all other tested ions (including potentially interfering anions such as F− and HPO42−) exerted negligible influence on the sensor’s fluorescence response.
To further assess the target recognition capability of Sensor ANT for CN− in complex matrices, competitive binding experiments were performed. After achieving complete fluorescence quenching of Sensor ANT by CN−, 10-fold excess of interfering ions was added to the pre-quenched system. As shown in Figure 3 (green bars), the introduction of 10 equivalents of interfering ions did not reverse or attenuate the CN−-triggered fluorescence quenching of Sensor ANT. These results demonstrate that Sensor ANT can selectively and sensitively recognize CN− even in the presence of high concentrations of competing ions, confirming its excellent anti-interference capability and reliable qualitative detection performance for CN−.

3.4. Binding Stoichiometry and Binding Constant

The binding affinity between a chemosensor and its target analyte is a critical determinant of overall sensing performance. The binding constant and stoichiometric ratio of Sensor ANT toward CN− were quantitatively determined via the Stern–Volmer equation. As depicted in Figure 4, the experimental data were well-fitted to the Stern–Volmer equation, yielding a binding constant (Ksv) of 1.95 × 104 M−1 and confirming a 1:1 binding stoichiometry between Sensor ANT and CN−. This result is consistent with the proposed binding mode (discussed below) and further supports the specificity of the interaction between Sensor ANT and CN−. Meanwhile, based on the test results of UV spectroscopy and the Stern–Volmer equation, we believe that the binding of Sensor ANT with CN− belongs to static quenching.

3.5. Fluorescence Quenching Efficiency and Binding Mechanism

The fluorescence quenching efficiency of Sensor ANT toward various metal ions and anions was quantitatively investigated. As illustrated in Figure 5, the quenching response triggered by CN− was remarkably prominent, reaching up to 77%, which was significantly superior to those observed for all other competitive ions. To elucidate the recognition mechanism of Sensor ANT for CN−, mass spectrometry and 1H NMR titration experiments were performed. The mass spectral results confirmed a 1:1 binding stoichiometry between the sensor and CN− (Figure S4), which was also consistent with the calculation results derived from the Stern–Volmer (KSV) equation. Furthermore, as shown in the inset of Figure 5, the 1H NMR titration profiles revealed that the proton signals corresponding to the two imino groups in Sensor ANT underwent obvious downfield shifts upon the addition of CN−, suggesting that the interaction between CN− and Sensor ANT was dominated by hydrogen bonding. On the basis of the 1:1 binding stoichiometry, the plausible binding mode of the ANT–CN− complex is proposed in the inset of Figure 5. Specifically, the cyanide anion forms intramolecular hydrogen bonds with the two imino (−NH−) moieties of Sensor ANT. Such hydrogen-bonding interaction triggers an intramolecular charge transfer (ICT) process, which effectively suppresses the radiative relaxation of the excited-state sensor molecules, thereby leading to the significant fluorescence quenching of Sensor ANT. This proposed sensing mechanism is further corroborated by the negligible spectral variations observed in the presence of other ions, which lack the specific binding affinity toward the imino sites necessary to induce the ICT process.

3.6. Response Time

Response time is a critical parameter for evaluating the practical application potential of fluorescent sensors. The response kinetics of Sensor ANT toward CN− were systematically investigated under physiological conditions (HEPES-NaOH buffer, pH 7.4) with both Sensor ANT and CN− at a concentration of 10 μM. As depicted in Figure 6, the fluorescence intensity of Sensor ANT underwent a rapid decrease upon the addition of CN−, and the quenching process reached equilibrium within 0.5 min. Compared to previously reported CN− sensors, Sensor ANT exhibited a faster response time due to the effect of hydrogen bonding [46,47]. This rapid response characteristic, coupled with the stable equilibrium state thereafter, enables Sensor ANT to serve as a promising candidate for the real-time and on-site monitoring of CN− in practical samples.

3.7. pH-Responsive

To investigate the influence of different pH conditions on the fluorescence intensity of Sensor ANT and Sensor ANT-CN−), their fluorescence responses were examined across a wide pH range. To maintain stable pH values, the following buffer systems were employed: HCl (pH 3–4), NaAc-HAc (pH 5–6), HEPES-NaOH (pH 7), NH3–NH4Cl (pH 8–11), and NaOH (pH 12). As depicted in Figure 7, Sensor ANT alone exhibited stable fluorescence intensity within the pH range of 5–9. Notably, its fluorescence intensity was significantly enhanced under acidic conditions, which can be attributed to protonation of the nitrogen atom in the acridine moiety at high H+ concentrations, thereby boosting its fluorescence. In contrast, increasing alkalinity promotes non-radiative relaxation pathways, resulting in fluorescence attenuation.
For Sensor ANT-CN−, fluorescence quenching was effectively maintained within pH 5–9. However, a pronounced fluorescence recovery was observed under strongly acidic conditions. This phenomenon likely arises from the competitive binding of excess H+ toward hydrogen-bonding sites, which weakens the intermolecular hydrogen-bonding interactions between Sensor ANT and CN− and reduces the extent of complex formation, thus restoring fluorescence. Similarly, under strongly alkaline conditions, the hydrogen-bonding network between Sensor ANT and CN− is disrupted, also leading to fluorescence enhancement.

3.8. Cytotoxicity Assay

To assess the potential applicability of Sensor ANT in biological systems, its cytotoxicity against HL-7702 normal liver cells was evaluated using the MTT assay. As shown in Figure 8, cell viability remained essentially unimpaired (≥90%) at Sensor ANT concentrations ranging from 0.1 to 10.0 μM. A mild reduction in cell viability was observed at elevated concentrations (50.0 and 100.0 μM), with the viability dropping to 69% at 100.0 μM. The half-maximal inhibitory concentration (IC50) of Sensor ANT against HL-7702 cells was calculated to be 201.3 μM. These findings demonstrate that Sensor ANT exhibits low cytotoxicity, particularly within the concentration range required for CN− detection (1–30 μM), confirming its suitability for in vivo CN− tracing applications.

3.9. Cellular and Zebrafish Imaging

To validate the biocompatibility of Sensor ANT and its capability for CN− tracking in biological systems, in vitro cellular imaging and in vivo zebrafish experiments were conducted. For cellular imaging: HL-7702 cells incubated with Sensor ANT alone (20 μM) exhibited robust fluorescence emission while retaining distinct cellular morphologies (Figure 9a,b), indicative of good biocompatibility and efficient cell membrane penetration. In stark contrast, upon the addition of CN− (20 μM), the fluorescence signal of the cells underwent pronounced quenching (Figure 9c), confirming that Sensor ANT can specifically respond to CN− in living cells.
For in vivo zebrafish imaging: Zebrafish incubated solely with Sensor ANT (10 μM) exhibited distinct fluorescence emission upon excitation at 365 nm (Figure 10a). In sharp contrast, negligible fluorescence signal was observed in zebrafish co-treated with Sensor ANT and CN− (10 μM) (Figure 10b). These results confirm the efficient internalization of Sensor ANT by zebrafish, with preferential accumulation in the gill and abdominal regions based on fluorescence intensity distribution. Collectively, the in vitro and in vivo imaging assays demonstrate that Sensor ANT possesses favorable membrane permeability and biocompatibility, rendering it a promising molecular sensor for real-time CN− detection in living biological systems.

3.10. Test Strip Experiment

In addition, filter paper was selected as the carrier for Sensor ANT for the convenient and rapid detection of CN−. The test strip for detecting CN− was prepared by uniformly dropping Sensor ANT solution onto neutral filter paper and drying it. Subsequently, solutions of the above-mentioned metal ions were dropped onto the surface of the test paper and placed under the irradiation of ultraviolet light, as shown in Figure 11; only CN− induced fluorescence quenching of the test strip, while other metal ions did not significantly affect the fluorescence signal of the test strip.

4. Conclusions

In summary, a novel acridine-based fluorescent sensor was rationally designed and synthesized for the selective and sensitive detection of CN−. Systematic characterizations using UV–Vis absorption and fluorescence emission spectroscopy confirmed that Sensor ANT exhibits excellent selectivity, high sensitivity, and rapid response kinetics toward CN−, with a low detection limit of 2.89 × 10−7 M. Beyond in vitro spectroscopic evaluations, the successful implementation of Sensor ANT for fluorescent imaging of CN− in living HL-7702 cells and zebrafish models validates its favorable biocompatibility, membrane permeability, and potential for biological applications. Collectively, these findings demonstrate that Sensor ANT represents a promising candidate for CN− detection in environmental and biological monitoring, laying a foundation for the design of advanced fluorescent sensors targeting anionic analytes. At the same time, there are currently some issues with sensors, such as uncontrolled preparation costs, unclear stability, and lack of further testing in practical applications. Therefore, in future research, these issues still need further breakthroughs.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/chemosensors14030067/s1, Figure S1: 1H NMR spectrum of Sensor ANT; Figure S2: 13C NMR spectrum of Sensor ANT; Figure S3: LC-MS of Sensor ANT; Figure S4: LC-MS of Sensor ANT-CN−.

Author Contributions

Conceptualization, C.Z. and Y.Z.; methodology, J.L. and E.K.; software, C.Z.; validation, Y.Z. and J.L.; formal analysis, J.L. and E.K.; investigation, Y.Z.; resources, J.L.; data curation, J.L. and E.K.; writing—original draft preparation, C.Z. and E.K.; writing—review and editing, C.Z.; visualization, J.L.; supervision, Y.Z.; and E.K. project administration, Y.Z.; funding acquisition, C.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Scientific Research Project of Jilin Provincial Department of Education, grant number JJKH20261817KJ.

Institutional Review Board Statement

All animal procedures were performed in accordance with the Guidelines for Care and Use of Laboratory Animals of Changchun University of Science and Technology, and experiments were approved by the Animal Ethics Committee of Changchun University of Science and Technology.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in this study are included in the article/Supplementary Materials. Further inquiries can be directed to the corresponding author.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Li, M.X.; Gao, Y.; Xu, K.; Zhang, Y.; Gong, S.; Yang, Y.; Xu, X.; Wang, Z.; Wang, S. Quantitatively analysis and detection of CN− in three food samples by a novel nopinone-based fluorescent probe. Food Chem. 2022, 379, 132153. [Google Scholar] [CrossRef]
  2. Xu, Z.; Chen, X.; Kim, H.N.; Yoon, J.Y. Sensors for the optical detection of cyanide ion. Chem. Soc. Rev. 2010, 39, 127. [Google Scholar] [CrossRef]
  3. Wu, L.; Liu, Y.; Wu, X.; Li, Y.; Du, J.; Qi, S.; Yang, Q.; Xu, H. A novel Near-Infrared fluorescent probe for Zn2+ and CN− double detection based on dicyanoisfluorone derivatives with highly sensitive and selective, and its application in Bioimaging. Spectrochim. Acta A 2022, 267, 120621. [Google Scholar] [CrossRef]
  4. Wei, T.B.; Li, W.T.; Li, Q.; Su, J.X.; Qu, W.J.; Lin, Q.; Yao, H.; Zhang, Y.M. A turn-on fluorescent chemosensor selectively detects cyanide in pure water and food sample. Tetrahedron Lett. 2016, 25, 2767. [Google Scholar] [CrossRef]
  5. Li, P.; Li, R.; Wang, K.; Liu, Q.; Ren, B.; Ding, Y.; Guan, R.; Cao, D. A julolidine-chalcone-based fluorescent probe for detection of Al3+ in real water sample and cell imaging. Spectrochim. Acta A 2022, 276, 121213. [Google Scholar] [CrossRef] [PubMed]
  6. Musile, G.; Grazioli, C.; Fornasaro, S.; Dossi, N.; De Palo, E.F.; Tagliaro, F.; Bortolotti, F. Application of paper-based microfluidic analytical devices (µPAD) in forensic and clinical toxicology: A review. Biosensors 2023, 13, 743. [Google Scholar] [CrossRef] [PubMed]
  7. Kumar, S.; Singh, P.; Hundal, G.; Hundal, M.S.; Kumar, S. A chemodosimeter for ratiometric detection of cyanide in aqueous media and human blood serum. Chem. Commun. 2013, 49, 2667–2669. [Google Scholar] [CrossRef]
  8. Wang, P.; Wang, Q.; Guo, Z.; Xue, S.; Chen, B.; Liu, Y.; Ren, W.; Yang, X.; Wen, S. A bifunctional peptide-based fluorescent probe for ratiometric and “turn-on” detection of Zn(II) ions and its application in living cells. Spectrochim. Acta A 2022, 268, 120653. [Google Scholar] [CrossRef]
  9. Patra, L.; Aich, K.; Gharami, S.; Mondal, T.K. A new carbazole-benzothiazole based chemodosimeter for chromogenic and fluorogenic detection of CN–. J. Lumin. 2018, 201, 419. [Google Scholar] [CrossRef]
  10. Xue, L.; Wang, R.; Qi, S.; Xu, H.; Wang, X.; Wu, L.; Yang, Q.; Du, J.; Li, Y. A novel 100% aqueous solution near-infrared ratiometric fluorescent CN− probe based on 1,4-dihydropyridines, with a large fluorescent emission peak shift. Talanta 2021, 225, 122100. [Google Scholar] [CrossRef] [PubMed]
  11. Tang, Q.; Dan, F.; Ma, S.; Zeng, X.; Lan, H. A colorimetric and fluorescent probe based on quinoline-indolium for detection of CN−. ChemistrySelect 2021, 6, 6557. [Google Scholar] [CrossRef]
  12. Wang, F.; Wang, L.; Chen, X.Q.; Yoon, J.Y. Recent progress in the development of fluorometric and colorimetric chemosensors for detection of cyanide ions. Chem. Soc. Rev. 2014, 43, 4312. [Google Scholar] [CrossRef]
  13. Wang, S.L.; Li, C.; Song, Q.-H. Fluorescent chemosensor for dual-channel discrimination between phosgene and triphosgene. Anal. Chem. 2019, 91, 5690–5697. [Google Scholar] [CrossRef]
  14. Kaur, I.; Sharma, V.; Mobin, S.M.; Kaur, P.; Singh, K. Excitation wavelength based reversible multicolour photoluminescence by a single chromophore upon aggregation: Detection of picric acid-application in bioimaging. Sens. Actuators B-Chem. 2018, 281, 613–622. [Google Scholar] [CrossRef]
  15. Ranolia, A.; Kiran; Sindhu, J.; Kumar, P.; Kumar, S. Divulging indolium inspired cyanide sensors: Did it win the throne? Coord. Chem. Rev. 2024, 498, 215463. [Google Scholar] [CrossRef]
  16. Huang, Y.; Zhang, Y.; Huo, F.; Wen, Y.; Yin, C. Design strategy and bioimaging of small organic molecule multicolor fluorescent probes. Sci. China Chem. 2020, 63, 1742–1755. [Google Scholar] [CrossRef]
  17. Yan, L.; Yang, H.; Li, J.; Zhou, C.; Li, L.; Wu, X.; Lei, C. A near infrared fluorescent probe for detection and bioimaging of zinc ions and hypochlorous acid. Anal. Chim. Acta 2022, 1206, 339750. [Google Scholar] [CrossRef]
  18. Duong, T.Q.; Kim, J.S. Fluoro- and chromogenic chemodosimeters for heavy metal ion detection in solution and biospecimens. Chem. Rev. 2010, 110, 6280. [Google Scholar] [CrossRef]
  19. Sun, Y.; Fan, S.W.; Duan, L.; Li, R.F. A ratiometric fluorescent probe based on benzo [e] indolium for cyanide ion in water. Sens. Actuators B-Chem. 2013, 185, 638. [Google Scholar] [CrossRef]
  20. Shahid, M.; Razi, S.S.; Srivastava, P.; Ali, R.; Maiti, B.; Misra, A. A useful scaffold based on acenaphthene exhibiting Cu2+ induced excimer fluorescence and sensing cyanide via Cu2+ displacement approach. Tetrahedron 2012, 68, 9076–9084. [Google Scholar] [CrossRef]
  21. Odago, M.O.; Colabello, D.M.; Lees, A.J. A simple thiourea based colorimetric sensor for cyanide anion. Tetrahedron 2010, 66, 7465–7471. [Google Scholar] [CrossRef]
  22. Ahmed, S.A.; Awad, M.I.; Althagafi, I.I.; Altass, H.M.; Morad, M.; Alharbi, A.; Obaid, R.J. Newly synthesized indolium-based ionic liquids as unprecedented inhibitors for the corrosion of mild steel in acid medium. J. Mol. Liq. 2019, 291, 111356. [Google Scholar] [CrossRef]
  23. Bhalla, V.; Singh, H.; Kumar, M. Triphenylene based copper ensemble for the detection of cyanide ions. Dalton Trans. 2012, 41, 11413–11418. [Google Scholar] [CrossRef]
  24. Jung, H.S.; Han, J.H.; Kim, Z.H.; Kang, C.; Kim, J.S. Coumarin-Cu(II) ensemble-based cyanide sensing chemodosimeter. Org. Lett. 2011, 13, 5056–5059. [Google Scholar] [CrossRef] [PubMed]
  25. Lou, X.; Zhang, L.; Qin, J.; Zhen, L. An alternative approach to develop a highly sensitive and selective chemosensor for the colorimetric sensing of cyanide in water. Chem. Commun. 2008, 44, 5848–5850. [Google Scholar] [CrossRef] [PubMed]
  26. Sun, M.D.; Guo, J.; Yang, Q.B.; Xiao, N.; Li, Y.X. A new fluorescent and colorimetric sensor for hydrazine and its application in biological systems. J. Mater. Chem. B 2014, 2, 1846. [Google Scholar] [CrossRef]
  27. Guo, Y.-Y.; Tang, X.-L.; Hou, F.-P.; Wu, J.; Dou, W.; Qin, W.-W.; Ru, J.-X.; Zhang, G.-L.; Liu, W.-S.; Yao, X.-J. A reversible fluorescent chemosensor for cyanide in 100% aqueous solution. Sens. Actuators B-Chem. 2013, 181, 202–208. [Google Scholar] [CrossRef]
  28. Bhalla, V.; Pramanik, S.; Kumar, M. Cyanide modulated fluorescent supramolecular assembly of a hexaphenylbenzene derivative for detection of trinitrotoluene at the attogram level. Chem. Commun. 2013, 49, 895. [Google Scholar] [CrossRef]
  29. Li, H.; Wen, Z.; Jin, L.; Kan, Y.; Yin, B. A coumarin-Meldrum’s acid conjugate based chemodosimetric probe for cyanide. Chem. Commun. 2012, 48, 11659–11661. [Google Scholar] [CrossRef]
  30. Yuan, L.; Lin, W.; Yang, Y.; Song, J.; Wang, J. Rational design of a highly reactive ratiometric fluorescent probe for cyanide. Org. Lett. 2011, 13, 3730–3733. [Google Scholar] [CrossRef]
  31. Li, H.; Li, B.; Jin, L.Y.; Kan, Y.; Yin, B. A rapid responsive and highly selective probe for cyanide in the aqueous environment. Tetrahedron 2011, 67, 7348–7353. [Google Scholar] [CrossRef]
  32. Kumar, A.; Vanita, V.; Walia, A.; Chae, P.S.; Kumar, S. Pyridoanthrone-based chromo-fluorogenic amphiphiles for selective CN− detection and their bioimaging application. Sens. Actuators B-Chem. 2020, 304, 127396. [Google Scholar] [CrossRef]
  33. Lv, X.; Liu, J.; Liu, Y.; Zhao, Y.; Sun, Y.Q.; Wang, P.; Guo, W. Ratiometric fluorescence detection of cyanide based on a hybrid coumarin-hemicyanine dye: The large emission shift and the high selectivity. Chem. Commun. 2011, 47, 12843–12845. [Google Scholar] [CrossRef] [PubMed]
  34. Li, Y.; Zhou, C.; Li, J.; Sun, J. A new phenothiazine-based fluorescent sensor for detection of cyanide. Biosensors 2024, 14, 51. [Google Scholar] [CrossRef]
  35. Zhou, C.; Song, Y.; Li, Y.P. A novel highly sensitive and selective fluorescent sensor for imaging mercury(II) in living cells. RSC Adv. 2014, 4, 33614. [Google Scholar] [CrossRef]
  36. Liu, X.; Chen, H.; Hu, X.; Liu, J.; Zhu, X.; Zhang, Y.; Liu, L. CN- as a cofactor enhancing the laccase-like activity of copper porphyrin metal-organic frameworks facilitates the sensitive cyanide detection. Sens. Actuators B-Chem. 2025, 442, 138135. [Google Scholar] [CrossRef]
  37. Dharaniprabha, V.; Kalavathi, A.; Satheeshkumara, K.; Kuppanagounder, P. ElangoA ferrocene-based chemo-dosimeter for colorimetric and electrochemical detection of cyanide and its estimation in cassava flour. Anal. Methods 2024, 16, 4880–4888. [Google Scholar] [CrossRef]
  38. Yu, M.; Jiang, L.; Mou, L.; Zeng, X.; Wang, R.; Peng, T.; Wu, F.; Shi, T. A “pincer” type of acridine–triazole fluorescent dye for iodine detection by both ‘naked-eye’ colorimetric and fluorometric modes. Molecules 2024, 29, 1355. [Google Scholar] [CrossRef]
  39. Gu, Y.; Gong, S.; Tian, J.; Meng, Z.; Liang, Y.; Gao, L.; Wang, Z.; Wang, S. A novel indolium-fused acridine-based bifunctional fluorescent probe for intracellular viscosity and sulfur dioxide applicate in environmental detection, bioimaging and real-time gas absorption monitoring. Sens. Actuators B-Chem. 2025, 443, 138229. [Google Scholar] [CrossRef]
  40. Hao, Y.; Zhang, Y.; Sun, Q.; Chen, S.; Tang, Z.; Zeng, R.; Xu, M. Phenothiazine-coumarin-pyridine hybrid as an efficient fluorescent probe for ratiometric sensing hypochlorous acid. Microchem. J. 2021, 171, 106851. [Google Scholar] [CrossRef]
  41. Zhou, C.; Sun, M.D.; Yan, C.Q.; Yang, Q.B.; Li, Y.X.; Song, Y. A new colorimetric and fluorescent chemodosimeter for fast detection of cyanide. Sens. Actuators B-Chem. 2014, 203, 382. [Google Scholar] [CrossRef]
  42. Wu, P.; Zhu, Y.; Chen, L.; Tian, Y.; Xiong, H. A fast-responsive OFF-ON near-infrared-II fluorescent probe for in vivo detection of hypochlorous acid in rheumatoid arthritis. Anal. Chem. 2021, 93, 13014. [Google Scholar] [CrossRef] [PubMed]
  43. Kim, Y.; Zhao, H.; Gabbaï, F.P. Sulfonium Boranes for the Selective Capture of Cyanide Ions in Water. Angew. Chem. Int. Ed. 2009, 48, 4957. [Google Scholar] [CrossRef]
  44. Shellaiah, M.; Awasthi, K.; Chandran, S.; Aazaad, B.; Sun, K.W.; Ohta, N.; Wu, S.P.; Lin, M.C. Methylammonium tin tribromide quantum dots for heavy metal ion detection and cellular imaging. ACS Appl. Nano Mater. 2022, 5, 2859–2874. [Google Scholar] [CrossRef]
  45. Tanwar, A.; Parui, R.; Garai, R.; Chanu, M.; Iyer, P. Dual “static and dynamic” fluorescence quenching mechanisms based detection of tnt via a cationic conjugated polymer. ACS Meas. Sci. Au 2022, 2, 23–30. [Google Scholar] [CrossRef] [PubMed]
  46. Wang, B.-B.; Wang, Y.; Wu, W.-N.; Xu, Z.-H.; Fan, Y.-C. A near-infrared colorimetric and fluorescent dual-channel probe for cyanide detection based on dicyanomethylene-4H-pyran. Inorg. Chem. Commun. 2020, 122, 108245. [Google Scholar] [CrossRef]
  47. Saha, P.P.; Chatterjee, T.; Pattanayak, R.; Das, R.S.; Guha, S. Targeting and imaging of mitochondria using near-infrared cyanine dye and its application to multicolor imaging. ACS Omega 2019, 4, 14579. [Google Scholar] [CrossRef]
Chemosensors 14 00067 sch001
Scheme 1. Synthetic route of Sensor ANT.
Scheme 1. Synthetic route of Sensor ANT.
Chemosensors 14 00067 sch001
Chemosensors 14 00067 g001
Figure 1. UV–Vis absorption spectra of Sensor ANT (5 × 10−4 mol/L) in the presence of different ions (5 × 10−4 mol/L) in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4).
Figure 1. UV–Vis absorption spectra of Sensor ANT (5 × 10−4 mol/L) in the presence of different ions (5 × 10−4 mol/L) in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4).
Chemosensors 14 00067 g001
Chemosensors 14 00067 g002
Figure 2. Fluorescence emission spectra of Sensor ANT (5 × 10−4 mol/L) in the presence of different concentrations of CN− (5 × 10−5–5 × 10−4 mol/L) in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4, λex = 390 nm). Inset: Linear relationship between fluorescence intensity and CN− concentration.
Figure 2. Fluorescence emission spectra of Sensor ANT (5 × 10−4 mol/L) in the presence of different concentrations of CN− (5 × 10−5–5 × 10−4 mol/L) in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4, λex = 390 nm). Inset: Linear relationship between fluorescence intensity and CN− concentration.
Chemosensors 14 00067 g002
Chemosensors 14 00067 g003
Figure 3. Selectivity experiments (orange bars) and competition experiments (green bars) of Sensor ANT for CN− detection in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4, λex = 390 nm, λem = 426 nm).
Figure 3. Selectivity experiments (orange bars) and competition experiments (green bars) of Sensor ANT for CN− detection in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4, λex = 390 nm, λem = 426 nm).
Chemosensors 14 00067 g003
Chemosensors 14 00067 g004
Figure 4. Stern–Volmer plot for the fluorescence quenching of Sensor ANT by CN− in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4, λex = 390 nm, λem = 426 nm).
Figure 4. Stern–Volmer plot for the fluorescence quenching of Sensor ANT by CN− in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4, λex = 390 nm, λem = 426 nm).
Chemosensors 14 00067 g004
Chemosensors 14 00067 g005
Figure 5. Fluorescence quenching efficiency of Sensor ANT (1 × 10−4 mol/L) in the presence of different ions (5 × 10−4 mol/L) at 426 nm (λex = 390 nm, λem = 426 nm). Inset: Plausible binding mode of the ANT–CN− complex.
Figure 5. Fluorescence quenching efficiency of Sensor ANT (1 × 10−4 mol/L) in the presence of different ions (5 × 10−4 mol/L) at 426 nm (λex = 390 nm, λem = 426 nm). Inset: Plausible binding mode of the ANT–CN− complex.
Chemosensors 14 00067 g005
Chemosensors 14 00067 g006
Figure 6. Response time profile of Sensor ANT (10 μM) upon the addition of CN− (10 μM) in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4, λex = 390 nm, λem = 426 nm).
Figure 6. Response time profile of Sensor ANT (10 μM) upon the addition of CN− (10 μM) in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4, λex = 390 nm, λem = 426 nm).
Chemosensors 14 00067 g006
Chemosensors 14 00067 g007
Figure 7. Effect of pH on the fluorescence intensities of Sensor ANT and Sensor ANT-CN− in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4, λex = 390 nm, λem = 426 nm).
Figure 7. Effect of pH on the fluorescence intensities of Sensor ANT and Sensor ANT-CN− in ethanol/HEPES-NaOH buffer solution (v/v = 1:1, pH 7.4, λex = 390 nm, λem = 426 nm).
Chemosensors 14 00067 g007
Chemosensors 14 00067 g008
Figure 8. Concentration-dependent cell viability of HL-7702 cells treated with Sensor ANT for 24 h (assessed by MTT assay).
Figure 8. Concentration-dependent cell viability of HL-7702 cells treated with Sensor ANT for 24 h (assessed by MTT assay).
Chemosensors 14 00067 g008
Chemosensors 14 00067 g009
Figure 9. (a) Bright-field image of HL-7702 cells treated with Sensor ANT (30 μM). (b) Fluorescence image of HL-7702 cells treated with Sensor ANT alone. (c) Fluorescence image of HL-7702 cells treated with Sensor ANT (20 μM) and CN− (20 μM).
Figure 9. (a) Bright-field image of HL-7702 cells treated with Sensor ANT (30 μM). (b) Fluorescence image of HL-7702 cells treated with Sensor ANT alone. (c) Fluorescence image of HL-7702 cells treated with Sensor ANT (20 μM) and CN− (20 μM).
Chemosensors 14 00067 g009
Chemosensors 14 00067 g010
Figure 10. Fluorescence images of adult zebrafish under UV light (365 nm): (a) zebrafish incubated with Sensor ANT alone (10 μM); (b) zebrafish incubated with Sensor ANT (10 μM) and CN− (10 μM).
Figure 10. Fluorescence images of adult zebrafish under UV light (365 nm): (a) zebrafish incubated with Sensor ANT alone (10 μM); (b) zebrafish incubated with Sensor ANT (10 μM) and CN− (10 μM).
Chemosensors 14 00067 g010
Chemosensors 14 00067 g011
Figure 11. Fluorescence changes of filter paper containing Sensor ANT treated with various ions under UV lamp.
Figure 11. Fluorescence changes of filter paper containing Sensor ANT treated with various ions under UV lamp.
Chemosensors 14 00067 g011
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Zhang, Y.; Zhou, C.; Li, J.; Kovtunets, E. A New Acridine-Based Fluorescent Sensor for the Detection of CN−. Chemosensors 2026, 14, 67. https://doi.org/10.3390/chemosensors14030067

AMA Style

Zhang Y, Zhou C, Li J, Kovtunets E. A New Acridine-Based Fluorescent Sensor for the Detection of CN−. Chemosensors. 2026; 14(3):67. https://doi.org/10.3390/chemosensors14030067

Chicago/Turabian Style

Zhang, Yiyuan, Chen Zhou, Jiaxin Li, and Evgeny Kovtunets. 2026. "A New Acridine-Based Fluorescent Sensor for the Detection of CN−" Chemosensors 14, no. 3: 67. https://doi.org/10.3390/chemosensors14030067

APA Style

Zhang, Y., Zhou, C., Li, J., & Kovtunets, E. (2026). A New Acridine-Based Fluorescent Sensor for the Detection of CN−. Chemosensors, 14(3), 67. https://doi.org/10.3390/chemosensors14030067

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop