Fluorogenic Detection Research Articles

Reactive Fluorescent and Colorimetric Probe for Highly Selective and Sensitive Detection of Hg2+ in Real Water Samples.

Construction of efficient chemosensors for highly specific and sensitive detection of mercury ions remains a great challenge. In this work a highly selective and sensitive probe CY was designed and synthesized by using coumarin fluorophore as the matrix and thioacetal moiety as the reactive recognition site for Hg2+. By virtue of the thiophilicity of Hg2+, probe CL could be hydrolyzed to deprotect and the thioacetal was transformed to the acyl group after the addition of Hg2+, the blue-green fluorescence was quenched and meanwhile the solution changed from light green to yellow. The detection limit of probe CY for Hg2+ was as low as 6.8 nM, and it could completely react with Hg2+ within 3min. Moreover, probe CY exhibited good resistance against interference from competitive metal ions and biothiols, high stability in pH 1-11 and applicability for fluorogenic and chromogenic dual-modal detection of Hg2+ in real water samples over a broad range of pH 5-10.

Turn-On Fluorescence Probe for Cancer-Related γ-Glutamyltranspeptidase Detection.

The design and development of fluorescent materials for detecting cancer-related enzymes are crucial for cancer diagnosis and treatment. Herein, we present a substituted rhodamine derivative for the chromogenic and fluorogenic detection of the cancer-relevant enzyme γ-glutamyltranspeptidase (GGT). Initially, the probe is non-chromic and non-emissive due to its spirolactam form, which hinders extensive electronic delocalization over broader pathway. However, selective enzymatic cleavage of the side-coupled group triggers spirolactam ring opening, resulting in electronic flow across the rhodamine skeleton, and reduces the band gap for low-energy electronic transitions. This transformation turns the reaction mixture from colorless to intense pink, with prominent UV and fluorescence bands. The sensor's selectivity was tested against various human enzymes, including urease, alkaline phosphatase, acetylcholinesterase, tyrosinase, and cyclooxygenase, and showed no response. Absorption and fluorescence titration analyses of the probe upon incremental addition of GGT into the probe solution revealed a consistent increase in both absorption and emission spectra, along with intensified pink coloration. The cellular toxicity of the receptor was evaluated using the MTT assay, and bioimaging analysis was performed on BHK-21 cells, which produced bright red fluorescence, demonstrating the probe's excellent cell penetration and digestion capabilities for intracellular analytical detection. Molecular docking results supported the fact that probe-4 made stable interactions with the GGT active site residues.

Supramolecular Guest Exchange in Cucurbit[7]uril for Bioorthogonal Fluorogenic Imaging across the Visible Spectrum.

Fluorogenic probes that unmask fluorescence signals in response to bioorthogonal reactions are a powerful new addition to biological imaging. They can significantly reduce background fluorescence and minimize nonspecific signals, potentially enabling real-time, high-contrast imaging without the need to wash out excess fluorophores. While diverse classes of highly refined synthetic fluorophores are now readily available, integrating them into a bioorthogonal fluorogenic scheme still requires extensive design efforts and customized structural alterations to optimize quenching mechanisms for each specific fluorophore scaffold. Herein, we present a highly generalizable strategy that can produce an efficient bioorthogonal fluorogenic response from essentially any readily available fluorophore without further structural alterations. We designed this strategy based on the macrocyclic cucurbit[7]uril (CB7) host, where a fluorogenic response is achieved by programming a guest exchange reaction within the macrocyclic cavity. We employed this strategy to rapidly create fluorogenic probes across the visible spectrum from diverse fluorophore scaffolds, which enabled no-wash imaging in live cells and tissues with minimal background signal. Finally, we demonstrated that this strategy can be combined with metabolic labeling for fluorogenic detection of metabolically tagged mycobacteria under no-wash conditions and paired with covalently clickable probes for high-contrast super-resolution and multiplexed imaging in cells and tissues.

NIR-Sensitive Squaraine Dye-Peptide Conjugate for Trypsin Fluorogenic Detection.

Trypsin enzyme has gained recognition as a potential biomarker in several tumors, such as colorectal, gastric, and pancreatic cancer, highlighting its importance in disease diagnosis. In response to the demand for rapid, cost-effective, and real-time detection methods, we present an innovative strategy utilizing the design and synthesis of NIR-sensitive dye-peptide conjugate (SQ-3 PC) for the sensitive and selective monitoring of trypsin activity by fluorescence ON/OFF sensing. The current research deals with the design and synthesis of three unsymmetrical squaraine dyes SQ-1, SQ-2, and SQ-3 along with a dye-peptide conjugate SQ-3-PC as a trypsin-specific probe followed by their photophysical characterizations. The absorption spectral investigation conducted on both the dye alone and its corresponding dye-peptide conjugates in water, utilizing SQ-3 and SQ-3 PC respectively, reveals enhanced dye aggregation and pronounced fluorescence quenching compared to observations in DMSO solution. The absorption spectral investigation conducted on dye only and corresponding dye-peptide conjugates in water utilizing SQ-3 and SQ-3 PC, respectively, reveals not only the enhanced dye aggregation but also pronounced fluorescence quenching compared to that observed in the DMSO solution. The trypsin-specific probe SQ-3 PC demonstrated a fluorescence quenching efficiency of 61.8% in water attributed to the combined effect of aggregation-induced quenching (AIQ) and fluorescence resonance energy transfer (FRET). FRET was found to be dominant over AIQ. The trypsin-mediated hydrolysis of SQ-3 PC led to a rapid and efficient recovery of quenched fluorescence (5-fold increase in 30 min). Concentration-dependent changes in the fluorescence at the emission maximum of the dyes reveal that SQ-3 PC works as a trypsin enzyme-specific fluorescence biosensor with linearity up to 30 nM along with the limit of detection and limit of quantification of 1.07 nM and 3.25 nM, respectively.

Ferrocene probe-assisted fluorescence quenching of PEI-carbon dots for NO detection and the logic gates based sensing of NO enabled by trimodal detection

Our research demonstrates the effectiveness of fluorescence quenching between polyethyleneimine functionalised carbon dots (PEI-CDs) and cyclodextrin encapsulated ferrocene for fluorogenic detection of nitric oxide (NO). We confirmed that ferrocene can be used as a NO probe by observing its ability to quench the fluorescence emitted from PEI-CDs, with NO concentrations ranging from 1 × 10–6 M to 5 × 10–4 M. The photoluminescence intensity (PL) of PEI-CDs decreased linearly, with a detection limit of 500 nM. Previous studies have shown that ferrocene is a selective probe for NO detection in biological systems by electrochemical and colorimetric methods. The addition of fluorogenic NO detection using ferrocene as a probe enables the development of a three-way sensor probe for NO. Furthermore, the triple mode NO detection (electrochemical, colorimetric, and fluorogenic) with ferrocene aids in processing sensing data in a controlled manner similar to Boolean logic operations. This work presents key findings on the mechanism of fluorescence quenching between ferrocene hyponitrite intermediate and PEI-CDs, the potential of using ferrocene for triple channel NO detection as a single molecular entity, and the application of logic gates for NO sensing.

Solid-Phase Extraction and Enhanced Amplification-Free Detection of Pathogens Integrated by Multifunctional CRISPR-Cas12a.

Public healthcare demands effective and pragmatic diagnostic tools to address the escalating challenges in infection management in resource-limited areas. Recent advances in clustered regularly interspaced short palindromic repeat (CRISPR)-based biosensing promise the development of next-generation tools for disease diagnostics, including point-of-care (POC) testing for infectious diseases. The currently prevailing strategy of developing CRISPR/Cas-based diagnostics exploits only the target identification and trans-cleavage activity of a CRISPR-Cas12a/Cas13a system to provide diagnostic results, and they need to be combined with an additional preamplification reaction to enhance sensitivity. In contrast to this dual-function strategy, here, we present a new approach that collaboratively integrates the triple functions of CRISPR-Cas12a: target identification, sequence-specific enrichment, and signal generation. With this approach, we develop a nucleic acid assay termed Solid-Phase Extraction and Enhanced Detection Assay integrated by CRISPR-Cas12a (SPEEDi-CRISPR) that negates the need for preamplification but significantly improves the detection of limit (LOD) from the pM to fM level. Specifically, using Cas12a-coated magnetic beads, this assay combines efficient solid-phase extraction and enrichment of DNA targets enabled by the sequence-specific affinity of CRISPR-Cas12a with fluorogenic detection by activated Cas12a on beads. SPEEDi-CRISPR, for the first time, leverages the possibility of employing CRISPR/Cas12a in nucleic acid extraction and integrates the ability of both enrichment and detection of CRISPR/Cas into a single platform. Our proof-of-concept studies revealed that the SPEEDi-CRISPR assay has great specificity to distinguish HPV-18 from HPV-16, and Parvovirus B19, in addition to being able to detect HPV-18 at a concentration as low as 2.3 fM in 100 min and 4.7 fM in 60 min. Furthermore, we proved that this assay can be coupled with two point-of-care testing strategies: the smartphone-based fluorescence detector and the lateral flow assay. Overall, these results suggested that our assay could pave a new way for developing CRISPR diagnostics.

Ratiometric Fluorescence and Chromogenic Probe for Trace Detection of Selected Transition Metals.

The design and development of a fluorescence sensor aimed at detecting and quantifying trace amounts of toxic transition metal ions within environmental, biological, and aquatic samples has garnered significant attention from diagnostic and testing laboratories, driven by the imperative to mitigate the health risks associated with these contaminants. In this context, we present the utilization of a heterocyclic symmetrical Schiff Base derivative for the purpose of fluorogenic and chromogenic detection of Co2+, Cu2+ and Hg2+ ions. The characterization of the ligand involved a comprehensive array of techniques, including physical assessments, optical analyses, NMR, FT-IR, and mass spectrometric examinations. The mechanism of ligand-metal complexation was elucidated through the utilization of photophysical parameters and FT-IR spectroscopic analysis, both before and after the interaction between the ligand and the metal salt solution. The pronounced alterations observed in absorption and fluorescence spectra, along with the distinctive chromogenic changes, following treatment with Co2+, Cu2+ and Hg2+, affirm the successful formation of complexes between the ligands and the treated metal ions. Notably, the receptor's complexation response exhibited selectivity towards Co(II), Cu(II), and Hg(II), with no observed chromogenic changes, spectral variations, or band shifts for the various tested metal ions, including Na+, Ag+, Ni2+, Mn2+, Pd2+, Pb2+, Cd2+, Zn2+, Sn2+, Fe2+, Fe3+, Cr3+ and Al3+. This absence of interaction between these metal ions and the ligand could be attributed to their compact or inadequately conducive conduction bands for complexation with the ligand's structural composition. To quantify the sensor's efficacy, fluorescence titration spectra were employed to determine the detection limits for Co2+, Cu2+ and Hg2+, yielding values of 2.92 × 10-8, 8.91 × 10-8, and 4.39 × 10-3 M, respectively. The Benesi-Hildebrand plots provided association constant values for the ligand-cobalt, ligand-copper, and ligand-mercury complexes as 0.74, 2.52, and 13.89 M-1, respectively.

Turn-on RNA Mango Beacons for trans-acting fluorogenic nucleic acid detection.

The Mango I and II RNA aptamers have been widely used in vivo and in vitro as genetically encodable fluorogenic markers that undergo large increases in fluorescence upon binding to their ligand, TO1-Biotin. However, while studying nucleic acid sequences, it is often desirable to have trans-acting probes that induce fluorescence upon binding to a target sequence. Here, we rationally design three types of light-up RNA Mango Beacons based on a minimized Mango core that induces fluorescence upon binding to a target RNA strand. Our first design is bimolecular in nature and uses a DNA inhibition strand to prevent folding of the Mango aptamer core until binding to a target RNA. Our second design is unimolecular in nature, and features hybridization arms flanking the core that inhibit G-quadruplex folding until refolding is triggered by binding to a target RNA strand. Our third design builds upon this structure, and incorporates a self-inhibiting domain into one of the flanking arms that deliberately binds to, and precludes folding of, the aptamer core until a target is bound. This design separates G-quadruplex folding inhibition and RNA target hybridization into separate modules, enabling a more universal unimolecular beacon design. All three Mango Beacons feature high contrasts and low costs when compared to conventional molecular beacons, with excellent potential for in vitro and in vivo applications.

Detection of the +3 Oxidation State of Metal Ions with the Aid of a Rhodamine‐Based Dye and Applications in Construction of Complex Logic Circuits and Living Cell Imaging

AbstractDetection of correct oxidation state of a metal ion is important to understand its speciation and redox properties. Some of rhodamine derivatives can identify Al3+, Cr3+ and Fe3+ as the trivalent cations. We have synthesized a rhodamine derivative, HL‐qui, from the reaction of N‐(rhodamine‐6G)lactam‐ethylenediamine with quinoline‐2‐carboxaldehyde for the colorimetric as well as fluorogenic detection of all of metal ions with +3 oxidation state such as Al3+, Cr3+, Fe3+, Ga3+, In3+, Tl3+ and Gd3+. In the presence of these trivalent cations, colorless and nonfluorescent HL‐qui turns pink and strongly fluorescent in HEPES buffer (10 mM) in H2O/ethanol=1/9 (v/v) (pH 7.4) as its spirolactam ring gets open to show the changes in color and fluorescence properties. High sensitivity of the probe towards the cations is reflected from the limit of detection values that are in nM range. To the best of our knowledge, there is no such report where fluorescence sensing has been utilized to determine oxidation state. This multi‐ion sensing feature has been used for fabrication of multi input‐output based logic circuit using Boolean algebraic method. It has been used in imaging of metal ions in living cell (L6 cells).

An imidazole functionalized aqua-stable metal-organic framework for selective fluorogenic detection of herbicide DNOC and antibacterial agent furaltadone in various biological and environmental specimens.

The widespread use of herbicides like dinitro-o-cresol (DNOC) and veterinary drugs such as furaltadone (FLT) has surged to meet agricultural and animal husbandry demands, raising significant health and environmental concerns due to their extensive use and unregulated disposal. To address this issue, herein, we developed an imidazole-functionalized metal-organic framework (MOF)-based fluorometric dual sensor for rapid and selective detection of these analytes in aqueous medium. The present MOF-based probe demonstrated 82% fluorescence quenching upon DNOC introduction, whereas 89% quenching occurred in the presence of FLT. The probe exhibited notably high sensitivity, with the lowest ever reported limit of detection (LOD) of 0.5 nM for DNOC and 1.1 nM for FLT. The highest reported Stern-Volmer quenching constant (KSV) value of 5 × 107 M-1 and 2 × 107 M-1 for DNOC and FLT, respectively, further indicates the extraordinary sensitivity of the sensor towards these targeted analytes. The MOF showed a rapid response time of 5 s for both DNOC and FLT. The sensor also demonstrated outstanding selectivity even in the presence of interfering substances, proving effective in various complex environments such as serum, urine, wastewater, and different pH media. We thoroughly investigated the sensor's working mechanisms using different advanced analytical techniques to understand its high selectivity towards the targeted analytes. These findings underscore the sensor's practical and potential real-world applications, offering a valuable tool for environmental pollution monitoring and public health protection.

Multi-Spectroscopic and TD-DFT Studies on Chromogenic and Fluorogenic Detection of Cyanide in an Aqueous Solution.

Different spectroscopic techniques and Density Functional Theory (DFT)/Time-Dependent Density Functional Theory (TDDFT) calculations have been employed to investigate the dual channel CN- detection behaviour of the developed chemo-dosimeter (AK3). The CN- with AK3 reaction triggered a colour change from pale yellow to colourless and enhanced fluorescence. UV-Vis, fluorescence, 1H & 13C NMR and mass techniques coupled with theoretical calculations (Mulliken charges, dihedral angles) revealed that the CN- sensing process mechanism involves deprotonation of the N-H group followed by nucleophilic addition reaction. Detailed TD-DFT calculations showed that the relaxation of excited electrons from LUMO and to two different ground states is responsible for the weak/moderate fluorescence of AK3. Nucleophilic addition of CN- to the C-atom of the CH = CH bridge terminated the π-conjugation between donor and acceptor regions, reduced the coplanarity, decreased the ICT transition and consequently enhanced the fluorescence of the probe. The practical utility of the probe was demonstrated by detecting cyanide in food materials and determining CN- in environmental water samples.

Reusable magnetic catalysed synthesis of fluorescent imidazole derivatives: Their use as chromogenic and fluorogenic probes for metal cation's detection

In this contribution, we report the design of magnetic functionalized nanocellulose by an in-Situ approach. The fabricated polymer matrix was utilized as an efficient heterogeneous catalyst for one-pot multi-component synthesis of fluorescent multi-substituted imidazoles under green optimized conditions. The eco-friendly protocol afforded, short reaction times, excellent yields and catalyst easy recycling through magnetic recovery. The geometric optimization, MEP and FMOs have also been carried out at B3LYP‐D3/6–311++G (d, p) level of Density Functional Theory simulations in ethanol to elucidate the substituent's effect on molecule's planarity, surface studies, their electronic structure as well as their intermolecular charge transfer. Furthermore, the synthesized multi-substituted Imidazole derivatives exhibited remarkable fluorescent properties explored in cation metal's chromogenic and fluorogenic detection.

Type Ι Photosensitizer Targeting G-Quadruplex RNA Elicits Augmented Immunity for Cancer Ablation.

Type Ι photodynamic therapy (PDT) represents a promising treatment modality for tumors with intrinsic hypoxia. However, type Ι photosensitizers (PSs), especially ones with near infrared (NIR) absorption, are limited and their efficacy needs improvement via new targeting tactics. We develop a NIR type Ι PS by engineering acridinium derived donor-π-acceptor systems. The PS exhibits an exclusive type Ι PDT mechanism due to effective intersystem crossing and disfavored energy transfer to O2 , and shows selective binding to G-quadruplexes (G4s) via hydrogen bonds identified by a molecular docking study. Moreover, it enables fluorogenic detection of G4s and efficient O2 ⋅- production in hypoxic conditions, leading to immunogenic cell death and substantial variations of gene expression in RNA sequencing. Our strategy demonstrates augmented antitumor immunity for effective ablation of immunogenic cold tumor, highlighting its potential of RNA-targeted type Ι PDT in precision cancer therapy.

A Gelation-Induced Enhanced Emission Active Stimuli Responsive and Superhydrophobic Organogelator: "Turn-On" Fluorogenic Detection of Cyanide and Dual-Channel Sensing of Nitroexplosives on Multiple Platforms.

A pyrene-based highly emissive low-molecular-weight organogelator, [2-(4-fluorophenyl)-3-(pyren-1-yl)acrylonitrile] (F1), is presented, which divulges thixotropic and thermochromic fluorescence switching via reversible gel-to-sol transition and tremendous superhydrophobicity (mean contact angles: 149-160°), devoid of any gelling and/or hydrophobic units. The rationale for the design strategy reveals that the restricted intramolecular rotation (RIR) in J-type self-assembly promotes F1 for the prolific effects of aggregation- and gelation-induced enhanced emission (AIEE and GIEE). Meanwhile, hindrance in charge transfer via the nucleophilic reaction of cyanide (CN-) on the C═C unit in F1 facilitates the selective fluorescence "turn-on" response in both solution [9:1 (v/v) DMSO/water] and solid state [paper kits] with significantly lower detection limits (DLs) of 37.23 nM and 13.4 pg/cm2, respectively. Subsequently, F1 discloses CN- modulated colorimetric and fluorescence "turn-off" dual-channel response for aqueous 2,4,6-trinitrophenol (PA) and 2,4-dinitrophenol (DNP) in both solution (DL = 49.98 and 44.1 nM) and solid state (DL = 114.5 and 92.05 fg/cm2). Furthermore, the fluorescent nanoaggregates of F1 in water and its xerogel films permit a rapid dual-channel "on-site" detection of PA and DNP, where the DLs ranged from nanomolar (nM) to sub-femtogram (fg) levels. Mechanistic insights reveal that the ground-state electron transfer from the fluorescent [F1-CN] ensemble to the analytes is responsible for anion driven sensory response, whereas the unusual inner filter effect (IFE) driven photoinduced electron transfer (PET) was responsible for self-assembled F1 response toward desired analytes. Additionally, the nanoaggregates and xerogel films also detect PA and DNP in their vapor phase with reasonable percentage of recovery from the soil and river water samples. Therefore, the elegant multifunctionality from a single luminogenic framework allows F1 to provide a smart pathway for achieving environmentally benign real-world applications on multiple platforms.

Type I Photosensitizer Targeting G‐Quadruplex RNA Elicits Augmented Immunity for Cancer Ablation

AbstractType I photodynamic therapy (PDT) represents a promising treatment modality for tumors with intrinsic hypoxia. However, type I photosensitizers (PSs), especially ones with near infrared (NIR) absorption, are limited and their efficacy needs improvement via new targeting tactics. We develop a NIR type I PS by engineering acridinium derived donor‐π‐acceptor systems. The PS exhibits an exclusive type I PDT mechanism due to effective intersystem crossing and disfavored energy transfer to O2, and shows selective binding to G‐quadruplexes (G4s) via hydrogen bonds identified by a molecular docking study. Moreover, it enables fluorogenic detection of G4s and efficient O2⋅− production in hypoxic conditions, leading to immunogenic cell death and substantial variations of gene expression in RNA sequencing. Our strategy demonstrates augmented antitumor immunity for effective ablation of immunogenic cold tumor, highlighting its potential of RNA‐targeted type I PDT in precision cancer therapy.

A highly sensitive colorimetric and fluorogenic detection of copper(II) ion based on new picolylamine-armed calix[4]arene

In this study, two- and tetra-functionalized with bis(2-picolyl)amine calix[4]arene derivatives (2-PACX and 4-PACX) were synthesized, and their structures were confirmed by 1H NMR, 13C NMR, FT-IR and TOF-MS spectroscopies. Cation sensing behaviors of them were investigated towards several cations such as Fe2+, Al3+, Cr3+, Hg2+, Mn2+, Cu2+, Co2+, Cd2+, Zn2+, Ni2+, Ag+, Mg2+, Ca2+, Li+, Na+, and K+. The results showed that 4-PACX was an effective colorimetric sensor against Cu2+ ions. The binding constant (K) value of the complexation between 4-PACX and Cu2+ ion was calculated as 4.62x108 M−2 and the detection limit value of the sensor as 5.1 μM. Moreover, the fluorescence studies demonstrated that 4-PACX has great fluorogenic sensor potential with 0.16 μM of detection limit. As a result, good yield, large coupling constant with Cu2+ ion (Ka = 13.972), applicability to aqueous samples, low detection limit, and high sensitivity were some of the advantages of the obtained sensor.

Paradoxical fluorescein-naphthalene Salamo-Salen-Salamo Zn(II) complex as a H2PO4−-targeted chemosensor and its application in water samples

Chemical materials with different properties could be directionally synthesized by introducing various functional groups into a molecular system. Here, an unusual naphthalene-fluorescein Salamo-Salen-Salamo-type Zn(II) complex was first developed as a fluorogenic chemosensor (ZnSS) based on a grafting design strategy. The in situ chemosensor ZnSS exhibits selective and efficient fluorogenic detection towards dihydrogen phosphate ion (H2PO4−) with off-on style in DMSOHEPES buffer. The synthesized chemosensor ZnSS could be applied to quantitatively analyze H2PO4− ion in rain water and tap water. Fluorescence quantum yield calculation was performed to study the luminescent properties of these compounds. Moreover, the mutual equilibrium of H2PO4− ion was studied by the transition state theory and vibration analysis of density functional theory (DFT). Time-dependent DFT (TDDFT) and electrostatic potential (ESP) calculations further explain the fluorescence emission characteristics and electronic excitation behavior in the sensing process.

An ICT-based organic framework for the fluorogenic detection of lethal pulmonary agent phosgene

A biphenyl-benzoimidazole based (BPCI) chemodosimeter has been developed for the rapid, sensitive and ratiometric detection of lethal pulmonary agent phosgene.

The how and why of naphthalimide/heterocycle-fused hybrid dyes: an overview of the latest developments in the quest for dyes with innovative optical properties.

In this review, a variety of hybrid structures fusing aromatic heterocycles of different natures to a naphthalimide backbone are discussed. This strategy constitutes an efficient approach to generate original structures displaying singular photophysical properties and thus offering new perspectives in the fields of fluorogenic detection, optoelectronics, and photodynamic therapy. In this review, different synthetic approaches and structures reported in the literature are discussed. A critical look at the design and the applications of these new fused hybrids allows us to evaluate the benefits and drawbacks of a fused hybrid strategy applied to naphthalimides.

Colorimetric and fluorogenic detection of nitrite anion in water and food based on Griess reaction of fluorene derivatives

New Griess reagents for nitrite determination were developed using two fluorene derivatives; 2-amino-7-bromofluorene (ABF) and 2-amino-7-bromo-9,9-dimethylfluorene (ABDF). The system of ABF is colorimetric sensor while the ABDF system is a dual-mode colorimetric and fluorogenic sensor. The diazotization reaction of ABF, NO2-, and β-naphthol in acid solution provided azo-dye product and led to an obvious color change from colorless to pink. The same reaction with ABDF displayed the color change to pink and a fluorescence quenching of ABDF emission. Under the optimal condition, colorimetric response, fluorogenic response, anion competition and detection limitation toward NO2- were determined using naked eye observation, UV-Vis and fluorescence technique. The lowest LOD (0.0007 mg L-1) was obtained from fluorescent method of ABDF. In addition, nitrite anion in different ham types were successfully analyzed using ABDF and fluorescent method which presented satisfactory performance parameters such as working range (0.0024 – 0.020 mg L-1), %recovery (83.36–107.68) and %RSD (0.26–3.77). According to paired t-test at a 95% confidence level, there was no significant differences between the results from the ABDF and those from the reference method. The practical application of ABF/ABDF sensors based on hydrogel indicator can be used for on-site monitoring of NO2- with a high sensitivity and selectivity by showing the same results of naked-eye color change and fluorescence turning off.