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A commercially available naphthalene fluorophore serves as a ratiometric indicator for albumin, showcasing its applications in albumin-based supramolecular recognition. [ABSTRACT FROM AUTHOR]

Intermolecular proton transfer from a flavonol-based probe to the arginine (Arg222) in drug site 1 of human serum albumin triggers an unusual red-shifted ratiometric fluorescence response, which can be applied in the point-to-care diagnosis of hypoalbuminemia. [ABSTRACT FROM AUTHOR]

Buprofezin (BUP) is an effective insecticide against Homopteran and Thysanoptera pests. However, exposure to BUP may result in several harmful effects on the non-target organism including human body, such as hepatotoxicity and DNA damage. Therefore, development of a reliable analytical method for BUP holds paramount importance. This study presents a novel albumin-based supramolecular biosensor, DPP@ALB, designed for the sensitive detection of BUP in environmental matrices, including water, soil, and real food samples. The features of this biosensor include a fast response, high sensitivity, and visually detectable fluorescence color change, enabling on-site detection of BUP based on the portable paper strips and 3D-printed miniaturized testing system. Overcoming challenges associated with the low chemical reactivity of BUP, this supramolecular biosensor emerges as the very first fluorescent sensor for efficient and reliable monitoring of BUP with applications in broader areas of environmental analysis and food safety. • The first ratiometric supramolecular biosensor for the detection of buprofezin. • The response is rapid (< 10 s) and the limit of detection is lower than 0.66 ppm. • Ratiometric response to buprofezin originates from the formation of co-binding albumin complex. • On-site detection of buprofezin has been achieved using a portable sensing device. • This biosensor enables detection of buprofezin in food samples and environmental matrices. [ABSTRACT FROM AUTHOR]

Albuminuria is a crucial urine biomarker of human unhealthy events such as kidney diseases, cardiovascular diseases, and diabetes. However, the accurate diagnosis of albuminuria poses a significant challenge owing to the severe interference from urine fluorescence and urine drugs. Here, we report a novel flavone-based fluorescent probe, DMC, by incorporating the FA1-targeting methylquinazoline group into a flavone skeleton with the extend π-conjugation. DMC exhibited a rapid response time, high sensitivity, and selectivity towards human serum albumin (HSA) in urine. Moreover, the red-shifted fluorescence and the FA1-targeted HSA-binding of DMC efficiently mitigated the interference from both urine fluorescence and urine drug metabolites. Furthermore, the establishment of a portable testing system highlighted the potential for point-of-care testing, offering a user-friendly and accurate approach to diagnose A2-level and A3-level albuminuria. We expect that the success of this DMC-based diagnostic platform in real urine samples can signify a significant advancement in early clinical diagnosis of albuminuria and its associated diseases. [Display omitted] [ABSTRACT FROM AUTHOR]

The first fluorescent sensor based on the indicator displacement assay (IDA) for on-site determination of etomidate. [ABSTRACT FROM AUTHOR]

Human serum albumin (HSA) is an important biomarker for chronic kidney disease, cardiovascular disease, and liver disease, yet its measurement is subject to the routine clinical laboratories. Pioneering studies have demonstrated that few of the ratiometric fluorescent probes enable the point-of-care (POC) testing of HSA with the aid of affordable domestic apparatuses. Still, the lack of choices of fluorophores restricts the development of such assay. In the present work, we propose two design strategies on the typical donor-acceptor fluorescent probe via the structural engineering. The results suggest that replacement of the dimethylamino group in probe by the weaker electron donating thiophene group can effectively tune the fluorescence response to HSA from off-on to ratiometric, ideally suiting for the POC application. The screened fluorescent probe is capable of detecting HSA with the features of fast response (< 10 s), stable output, high sensitivity (limit of detection = 54 nM), tunable detection range, and great anti-interference. Moreover, the ratiometric fluorescence response to HSA can be recorded and analyzed by the portable miniaturized paper-based or 3D-printed devices at the point of need. The success of structural engineering in the present study provides an efficient way to rationally regulate the fluorescence response mode of the donor-acceptor probes. [Display omitted] ● A donor-acceptor-based probe STF for ratiometric detection of HSA is reported. ● The relationship between structure and spectroscopic properties of probe is revealed. ● STF enables the rapid, sensitive, and selective detection of HSA. ● The portable paper-based testing devices and 3D-printed miniaturized devices are integrated. ● The point-of-care testing of HSA is achieved. [ABSTRACT FROM AUTHOR]

Nitroxynil (NTX) is a common anthelmintic veterinary drug for the management of fascioliasis in food-producing sheep and cattle. Since excessive NTX residue in food can lead to several adverse side effects, such as allergic skin reaction and respiratory irritation, it is of great importance to develop an efficient analytical method for NTX determination. Herein, we report a simple fluorescent detection method based on a novel supramolecular probe capable of detecting NTX with a fast response (5 s), high sensitivity (107 nM), high selectivity, and acceptable anti-interference property. Moreover, the portable paper-based test strips were facilely prepared and successfully realized on-site determination of NTX in real edible animal products simply with the aid of a smartphone. To the best of our knowledge, this is the very first report on the portable detection of NTX. This study also provides a promising strategy for the fast and portable detection of analyte based on the host-guest system, which will lead to improved fluorescent probe design for food analysis. [Display omitted] • An albumin-based supramolecular probe for nitroxynil detection was reported. • This probe enabled detecting nitroxynil with fast response and high sensitivity. • A portable paper-based testing device was fabricated based on this probe. • On-site determination of nitroxynil in real food samples was achieved. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel ratiometric probe for hydrogen peroxide is reported. • The protein-based strategy converts off-on type response into the ratiometric one. • This method enables the portable detection with a 3D-printed miniaturized testing system. • Smartphone-based on-site detection of hydrogen peroxide in real milk samples was achieved. The on-site detection of hydrogen peroxide (H 2 O 2) is important for maintaining food safety as the ingestion of H 2 O 2 can lead to serious pathological conditions. However, most reported fluorescent probes require a fluorometer to ensure readable signal output and reliable detection result. Consequently, the fluorescent detection of H 2 O 2 can be realized only within a standard laboratory setting. Herein, we report a novel supramolecular strategy that can successfully convert the typical off-on response to H 2 O 2 into a ratiometric response, which allows the on-site detection of H 2 O 2 when used in conjunction with a smartphone-based 3D-printed miniaturized testing system. This method has acceptable sensitivity, good anti-interference ability, and desirable accuracy compared to a standard detection method. More importantly, this portable ratiometric method can be used to detect H 2 O 2 residue in commercial milk samples with the simple testing apparatuses. [ABSTRACT FROM AUTHOR]

The widespread occurrence of hydrazine residues in the environment, including in water, soil, and organisms, is a potential health threat to humans. Therefore, the development of an efficient method for the detection of hydrazine in environmental samples is highly desirable although it poses a significant challenge. In this study, we designed and synthesized a series of naphthalene-based fluorescent dyes through structural engineering and developed a novel probe for hydrazine detection. The probe could provide a distinct fluorescence response toward hydrazine in aqueous solution with high sensitivity and selectivity. Moreover, paper-based test strips can be easily fabricated using this probe, enabling the portable on-site detection of hydrazine with the aid of a smartphone. Furthermore, we demonstrated that this probe is capable of recognizing hydrazine in various environmental samples, including water, soil, plants, and zebrafish embryos. This research provides a promising tool for the detection of hydrazine in the environment. [Display omitted] • A novel naphthalene-based fluorescent probe for hydrazine detection is reported. • This probe exhibits sensitive and selective response towards hydrazine in water. • Portable detection of hydrazine is achieved with the aid of a smartphone. • Accurate determination of hydrazine is realized in real environmental samples. [ABSTRACT FROM AUTHOR]

A colorimetric and fluorescent dual probe for CO is designed and synthesized. The probe is capable of sensitive and specific detection of CO with naked-eye through colorimetric assay in phosphate buffer from colorless to yellow, which also features 75-fold turn-on fluorescence enhancement upon exciting at 480 nm with the detection limit of 26.3 nM. The probe shows great potential for sensing intracellular CO without the interference in living cell imaging. On the other hand, the probe could also be utilized as an efficient and convenient visual indicator for CO gas in air by naked eyes. [ABSTRACT FROM AUTHOR]

• The strategy of donor engineering to enhance fluorescence brightness is reported. • The methylpiperazine-substituted flavonoid shows high fluorescence brightness in water. • A novel fluorescent probe can sense cysteine both in water and in living cells. Increasing demand for detecting environmental and biological analytes in aqueous solutions based on fluorescent probes has raised the bar for the fluorophores used. Especially, the twisted intramolecular charge transfer (TICT) state of fluorophore can trigger the formation of a charge-separated non-emissive specie, leading to a low fluorescence brightness. In this work, we performed a simple donor engineering on the flavonoid-based fluorophores to regulate the TICT formation. A systematic study on relationship between donor structure and photophysical properties has been carried out. Among a series of flavonoids, the methylpiperazine-substituted one exhibited the strongest fluorescence brightness in water since the methylpiperazine could rigidify the rotation of donor moiety to suppress TICT state. Moreover, a novel fluorescent probe based on this flavonoid successfully realized the cysteine detection both in water and in living cells. This work confirmed the validity of design strategy by inhibiting TICT to enhance the fluorescence brightness, and also provided a practical flavonoid-based fluorophore for further bioimaging applications. [ABSTRACT FROM AUTHOR]

Monitoring of cysteine (Cys) is of significant importance for studying Cys-involved biological functions and clinically diagnosing Cys-related diseases. Recently, few fluorescent probes with two different reacting sites were reported to be capable of sensing different concentration ranges of Cys with distinct fluorescence signals, particularly suiting for bioimaging. However, due to relative sophisticated synthesis and moderate selectivity, the applications of these probes were still severely restricted. In this work, we proposed a novel probe design strategy by utilizing two same reacting groups, instead of two different reacting groups, to simplify the synthesis route and minimize the interference from competing species. Same reacting groups in a probe with different steric hindrances could exhibit different reactivities to Cys. This probe showed distinguishable fluorescence peak wavelengths towards low and high concentration ranges of Cys, giving green and blue emissions, respectively. Moreover, this probe was successfully applied for monitoring of Cys concentration in living cells. We believe this work provided a simpler strategy for dual-site fluorescent probes to sense difference concentration ranges of Cys, which may inspire more probe design in future. [Display omitted] • A novel fluorescent probe with dual acrylate sites was designed and synthesized. • The probe enables discrimination of different concentration ranges of cysteine. • Same reacting groups in one probe with different steric hindrances could exhibit different reactivities to cysteine. • This probe was successfully applied for monitoring of cysteine concentration in living cells. [ABSTRACT FROM AUTHOR]

A commercial anti-cancer drug, axitinib, exhibits very stable dual emissions for discrimination of human serum albumin. [ABSTRACT FROM AUTHOR]

Simultaneous detection of two or more biothiols by using fluorescent methods is in particular importance for biological research and disease diagnosis. Because (1) the variation of one biothiol level under specific cellular metabolism may lead to the change of another biothiol, and (2) several diseases such as Alzheimer's disease associate with joint action from two or more biothiols. In this paper, we provide an overview of the fluorescent probes with multiple channels that have been applied to simultaneous detection of biothiols. The present review highlights the basic characteristics of probes with multi-channel in the respect of design principle, photophysical process, sensing mechanism, sensing performance, and bioapplications. This review aims to offer a comprehensive summary for researchers to inspire new probe design, and also push forward the advancement of simultaneous detection of biothiols based on multi-channel probes. • The fluorescent probes with multiple channels for simultaneous detection of biothiols are reviewed. • The necessity of simultaneous detection of biothiols is introduced. • The design mechanism of fluorescent probes with multiple channels has been discussed and categorized. • The overall sensing performances and bioapplications of probes are summarized. [ABSTRACT FROM AUTHOR]

Tetracyclines (TCs) are a group of broad-spectrum antibiotics against multiplying microorganisms yet with several adverse effects on humans. Since all types of TCs have the similar chemical skeleton and mechanism of action, quantification of total amount of TCs in the environment was of particular importance. To date, dozens of fluorescent probes have been reported for TCs detection, but only very few of them enabled detection of total TCs. In this study, we report a novel supramolecular sensor constructed by human serum albumin as the recognition moiety and a flavonol fluorophore as the indicator. Under the 370 nm UV excitation, this sensor exhibits the rapid response (5 s), acceptable sensitivity (limit of detection ∼ 0.58 μM), long dynamic detection range (0–20 μM), prominent specificity, and excellent anti-interference properties for analysis of total TCs. The mechanism was carefully validated using 1H NMR, fluorescence titration experiments, molecular docking, and mass spectrometry. We expect this work can inspire more sensor design for TCs quantification. [Display omitted] • A novel fluorescent sensor enables detection of total amount of tetracyclines. • This method can detect tetracycline with rapid response and high selectivity. • The limit of detection for tetracyclines can reach 0.58 μM. • Accurate detection of total tetracycline in real samples is achieved. [ABSTRACT FROM AUTHOR]

Closantel is widely used in the management of parasitic infestation in livestock, but is contraindicated in humans due to its high toxic to human retina. Thus, development of a fast and selective method for the detection of closantel residues in animal products is highly needed yet still challenging. In the present study, we report a supramolecular fluorescent sensor for closantel detection through a two-step screening process. The fluorescent sensor can detect closantel with a fast response (<10 s), high sensitivity, and high selectivity. The limit of detection is 0.29 ppm, which is much lower than the maximum residue level set by government. Moreover, the applicability of this sensor has been demonstrated in commercial drugs tablets, injection fluids, and real edible animal products (muscle, kidney, and liver). This work provides the first fluorescence analytical tool for accurate and selective determination of closantel, and may inspire more sensor design for food analysis. [Display omitted] • The first fluorescent detection method for closantel is reported. • This sensor can detect closantel with a fast response, high sensitivity, and high selectivity. • The limit of detection to closantel is 0.29 ppm. • This method enables on-site determination of closantel in real food samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • The first pH fluorescent sensor with two pKa values. • This sensor enables monitoring of pH with the dual-color response. • The portable paper strips can be facilely fabricated based on the sensor. • The paper strips can be successfully employed for the real food analysis. Tracking pH fluctuations in food samples is important for ensuring food freshness. Fluorescent probes have been widely applied as promising tools for the on-site detection of pH changes; however, most of them can be applied only at either lower or higher pH ranges because their response structures commonly have a single acid dissociation constant (pKa). To address this problem, we designed a fluorescent sensor, called HMB, containing a methylpiperazine group with two pKa values, which exhibited a unique dual-color response to pH changes over a wide pH range. Furthermore, the HMB-based test strips are easily prepared and used as portable labels for the visual monitoring of food spoilage that results in microbial and anaerobic glycolytic pathways in real food (such as cheese and shrimp). To the best of our knowledge, this is the first fluorescent pH sensor with two pKa values, and we expect that this work will inspire more sensor designs for food quality control. [ABSTRACT FROM AUTHOR]

Ochratoxin A (OTA), a mycotoxin found in various food items, possesses significant health risks due to its carcinogenic and toxic properties. Thus, detecting OTA is crucial to ensure food safety. Among the reported analytical methods, there has yet to be one that achieves fast, selective, and portable detection of OTA. In this study, we explore a novel supramolecular sensor, DOCE@ALB, utilizing human serum albumin as the host and a flavonoid fluorescent indicator as the guest. On the basis of indicator displacement assay, this sensor boasts an ultra-fast response time of just 5 s, high sensitivity with a limit of detection at 0.39 ppb, exceptional selectivity, and a noticeable ratiometric fluorescence response to OTA. This discernible color change and portability of the sensor make it suitable for on-site OTA detection in real food samples, including flour, beer, and wine, simply using a smartphone. In comparison to previously reported methods, our approach has showcased notable advantages in both response time and portability, addressing a critical need for food safety and regulatory compliance. [Display omitted] • The first fluorescent sensor enables rapid and portable detection of Ochratoxin A (OTA). • The limit of detection for OTA is 0.39 ppb. • This sensor exhibits a noticeable emission color response to OTA. • The sensor-based paper strips and integrated testing device were studied for the smartphone-based analysis. • This sensor is capable of on-site detection of OTA in flour, beer, and wine samples [ABSTRACT FROM AUTHOR]

[Display omitted] • This work reported the first ratiometric fluorescent probe for nitroxinil. • The probe enables fast, sensitive and selective detection of nitroxinil. • On-site analysis in real food samples was available by using paper strips. • Fluorescence imaging of nitroxinil in Hela cells was successfully achieved. Nitroxinil (NIT) is a widely using veterinary medicine to protect cattle and sheep yet may threaten human health when ingested through food chain. Developing fluorescent analytical methods in ratiometric manners was essential for the on-site detection and in-situ monitoring of NIT but still challenging. Here, we improved the indicator-displacement assay (IDA)-based method and designed the first ratiometric fluorescent probe for NIT by using an albumin host and an Aggregation-induced emission (AIE) guest. This probe exhibited fast response (10 s), high sensitivity (limit of detection: 4.6 ppb), good selectivity (over twelve medicines) and eye-discriminable fluorescent color change (green–red) upon responding to NIT. Based on these properties, this probe enabled quantitative determination of NIT in real food samples, on-site analysis via a paper-based test strip, and fluorescence imaging of NIT in living cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The flavonol-based small-molecule fluorescent probes are reviewed. • ƒÜ The unique photophysical process of flavonol and its advantages in probe design are introduced. • ƒÜ The design mechanism of flavonol-based fluorescent probes has been discussed and categorized. • ƒÜ The sensing performances and applications of probes are summarized. Flavonols, named as 3-hydroxyl-2-phenyl-1-benzopyran-4-one, are important natural botanical functional pigments widely distributing in fruits, vegetables, and flowers. Owing to intramolecular hydrogen bond, the flavonols can undergo the excited-state intramolecular proton transfer (ESIPT) process upon irradiation, leading to unique environmental-sensitive dual emissions, which makes flavonol an ideal fluorophore skeleton for probe design. In this paper, we summarized the recent progress of flavonol-based small-molecule fluorescent probes for diverse sensing applications, including detection of anions, cations, reactive biological species, proteins, DNAs, environmental hazards, and microenvironmental factors. This review highlighted the basic characteristics of flavonol probes in the respect of design principles, photophysical processes, sensing mechanism, sensing performances, and biological applications. The present review article aims to offer a comprehensive summary for researchers to inspire new probe design, and push forward the advancement of flavonol-based fluorescent probes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The first fluorescent sensor for ratiometric detection of permethrin is reported. • This sensor exhibited rapid response, high sensitivity and high selectivity. • The limit of detection for permethrin was 0.08 μM (29 ppb). • This sensor successfully achieved monitoring of permethrin in real food samples. Permethrin (PMT) is a broad-spectrum synthetic pyrethroid insecticide widely used for treatment of insects in agriculture. Yet the massive use of PMT comes at the cost of its residue ubiquitous in the environment thereby causing a significant risk to human health. Therefore, development of an analytical method for accurate detection of PMT at the point-of-care is of great importance. In this study, we report a novel single-fluorophore-based supramolecular sensor with dual emissions as ratiometric output signals, successfully realizing the fast detection of PMT with the self-calibrating feature. This sensor exhibited several advantages for PMT detection, such as fast response, high sensitivity, high specificity, and excellent anti-interference property. Notably, this sensor could be used for on-site monitoring of PMT residues on the food surface without the help of complicated testing facilities. To our best knowledge, this is the first promising fluorescent method for the fast and ratiometric determination of PMT. [ABSTRACT FROM AUTHOR]

The hydroxyl substituent in flavonoids can cause the binding site to change from DS1 to DS2 and restore the ESIPT process of flavonoids, thereby leading to a unique dual-emissive response towards human serum albumin. [ABSTRACT FROM AUTHOR]

• A novel supramolecular probe based on a dual-state-emission chalcone is reported. • This probe for the first time achieves rapid, sensitive, and ratiometric detection of penconazole. • Probe-loaded paper-based test strips were fabricated for smartphone-based portable detection. • This probe can be used for the on-site analysis of water, soil, and food. Penconazole (PEN) is a systemic triazole fungicide widely pulverized on fruits and vegetables to control powdery mildew disease. PEN has various hazardous effects on mammalians primarily through PEN-induced excessive generation of reactive oxygen species, which may cause metabolic disorders, cancer, etc. Therefore, development of an effective analytical method for PEN is of great importance for the environmental safety and human health. In the present work, we report a supramolecular fluorescent probe OPyCH@ALB constructed by selecting of a dual-state-emission chalcone as the indicator and albumin as the host, for the first time, successfully realizing the ratiometric detection of PEN. This probe is capable of detecting PEN with rapid response (10 s), high sensitivity (LOD = 0.28 μM, 76 ppb), high selectivity, and a visible fluorescence color change from green to red. Based on this probe, the portable paper-based test strips, which enable the on-site monitoring of PEN without the involvement of any complicated testing apparatus, were fabricated. Furthermore, this probe was used to realize the qualitative and quantitative analysis of PEN in ground water and soil with high accuracy, and successful achieved on-site recognition of PEN on the surface of grapes. We expect that this method will be applied as a convenient and affordable tool for the rapid monitoring of PEN at the point-of-use, such as in residential, agricultural, and food production settings. [ABSTRACT FROM AUTHOR]

Chlorpyrifos (CPF) as a classic organophosphorus pesticide has been widely used in agricultural applications to control insects and worms. CPF in the environment can cause deaths of diverse kinds of aquatic organism and bring a high risk to human health. Therefore, the development of effective analytical method for CPF is of great importance. In this work, a novel dual-mode albumin (ALB)-based supramolecular probe FD@ALB was designed and prepared for rapid detection of CPF in the environment. The limit of detection is 0.57 μM (∼ 0.2 ppm) with a wider detection range up to 200 μM, which is satisfactory for application. The sensing mechanism can be ascribed to CPF-induced phosphorylation of ALB, thus leading to a change in the binding microenvironment of FD dye. Moreover, the paper-based test strips were used in conjunction with the FD@ALB, realizing the portable detection of CPF. This method was demonstrated to be suitable for on-site detection of CPF in various kinds of environmental samples, including water, soil, and food samples, with the aid of a smartphone. To the best of our knowledge, this is the first analytical method achieving a combination of the rapid and ratiometric detection of CPF in the environment. [Display omitted] • The first ratiometric supramolecular fluorescent probe can rapidly detect chlorpyrifos. • This probe is applicable over a broad concentration range (0–200 μM). • The limit of detection for chlorpyrifos was 0.57 μM. • Dual-mode sensing mechanism is validated by mass spectra and dynamic light scattering. • This probe is capable of on-site detection of CPF in various environmental samples [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel functional material as the host–guest supramolecular probe was reported. • This work for the first time reported a ratiometric detection method for cyfluthrin. • The probe enables fast, sensitive (LOD 70 ppb), and selective detection of cyfluthrin. • The paper-based testing device was utilized for the smartphone-based analysis. • On-site determination of cyfluthrin in real food samples could be successfully realized. The massive use of cyfluthrin pesticide in agriculture has brought growing concerns on the food safety due to its chemical stability, easy-to-accumulation, and several harmful effects on human health. Design of a rapid, reliable and portable analytical method for on-site monitoring cyfluthrin is of great significance. Although reported assays showed high sensitivity and selectivity to cyfluthrin, these intensity-based outputs suffered from the interference from a variety of analyte-independent factors, i.e. the instrumental parameters, which often led to the poor accuracy and repeatability of detection results. In this work, we reported a novel host–guest supramolecular probe by using albumin as the host and solvatofluorochromic flavonoid as the guest, for the first time, successfully realizing ratiometric determination of cyfluthrin. This probe was capable of detecting cyfluthrin with the fast response (10 s), high sensitivity (LOD ∼70 ppb) and selectivity, good anti-interference performance, and remarkably distinct emission color change from orange to green. Moreover, the portable paper-based test strips could be facilely obtained and utilized for ratiometric determination cyfluthrin pesticide in food samples, such as apple, tomato, cucumber. The signal outputs could be captured and analyzed by using a smartphone, demonstrating the application potential of this probe in on-site food analysis. We expected this work may open up a novel avenue for on-site determination of pesticides with the simple testing apparatuses. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel red-emissive ESIPT-based quinolone probe enables ratiometric detection of phosgene. • This probe exhibits the rapid response (in 10 s), stable signal output (last for 10 min), high sensitivity (LOD ∼ 6.7 nM), and distinct emission color change (red to green) towards phosgene. • The sensing mechanism have been investigated by using 1H NMR, HRMS and fluorescence lifetime techniques, confirming that amidation reaction effectively suppressed the ESIPT process. • The probe-embedded nanofibers were facilely prepared by electrospinning and successfully employed to monitor gaseous phosgene with high specificity. Phosgene is a highly toxic gas that poses a serious threat to human health and public safety. Therefore, it is of great importance to develop an available detection method enabling on-the-spot measurement of phosgene. In this paper, we report a novel ESIPT fluorescent probe for phosgene detection based on quinolone fluorophore. This probe exhibits rapid response (in 10 s), stable signal output (last for 10 min), high sensitivity (LOD ∼ 6.7 nM), and distinct emission color change (red to green) towards phosgene. The sensing mechanism was investigated by using 1H NMR, HRMS and fluorescence lifetime techniques, confirming that the amidation reaction between phosgene and quinolone effectively suppressed the ESIPT process of probe. Eventually, this probe was fabricated into polymer nanofibers by electrospinning and successfully employed to monitor gaseous phosgene with high specificity. This work provided a promising analytical tool for rapid and ratiometric detection of phosgene both in solution and in the gas phase. [ABSTRACT FROM AUTHOR]

[Display omitted] • A surfactant-assisted fluorescent method is reported for sensitive detection of benfluralin herbicide in water with a LOD of 80 nM. • The role of surfactant on signal amplification has been carefully studied by the polarity-dependent DFT calculation. • The sensing properties including response time, sensitivity, selectivity, and anti-interference ability, have been fully studied. • This surfactant-assisted method enables the fluorescent monitoring of benfluralin in living plants. Developing an effective detection method for benfluralin (BFA) is of great significance, since BFA as most widely used herbicides can be bioaccumulated by aquatic organisms in environment, possessing potential risks to human health. Owing to aggregation-caused quenching effect, most fluorescent detection methods based on donor–acceptor organic fluorophores suffered from very low sensitivity towards BFA in water system, hampering the bioimaging application in plants. In this work, we reported a novel surfactant-assisted fluorescent probe enabling detection of BFA in water with a high sensitivity. The involvement of specific surfactant Triton X100 (TX100) could amplify the response signal of probe more than 100-fold. The detection limit for BFA was determined to be 80 nM, satisfying the environmental protection requirements. Moreover, we demonstrated applications of this strategy for the fluorescent imaging of BFA in plant. The absorbance of BFA into roots of Arabidopsis thaliana and castor seedlings was successfully observed based on this method. [ABSTRACT FROM AUTHOR]

[Display omitted] • A dicyanoisophorone-based fluorescent probe DCO2 with twisted N,N-diethylamino as donor is reported for the discrimination of HSA from BSA. • DCO2 could selectively bind with HSA compared to previous probe DCO1. • Experimental results indicated that specific spectral response to HSA was ascribed to the rigid donor structure and steric hindrance of DCO2. • DCO2 could accurately and sensitively detect HSA in the biological fluids. Despite the rapid development of fluorescent probe techniques for the detection of human serum albumin (HSA), a probe that discriminates between HSA and bovine serum albumin (BSA) is still a challenging task, since their similar chemical structures. As a continuation of our work, herein, a dicyanoisophorone-based fluorescent probe DCO2 is systematically studied for discrimination of HSA from BSA. The photophysical and sensing performances of DCO2 , including basic spectroscopic properties, sensing sensitivity, and selectivity, exhibits that DCO2 could selectively bind with HSA and display remarkable fluorescence enhancement (∼254-fold) at 685 nm. The gap of the fluorescent response of DCO2 between HSA and BSA is an obvious increase from 21% to 73% compared to the previous probe DCO1. The sensing mechanism was elucidated by Job's plot, displacement experiment, and molecular docking, suggesting that the specific response to HSA originated from the rigid donor structure and steric hindrance. DCO2 could be buried in the DS1 pocket of HSA, and only partly wedged into the DS1 pocket of BSA with exposing twisted N,N-diethylamino group outside. Application studies indicated that DCO2 has well detective behavior for HSA in the biological fluids. This work could provide a new approach to design HSA-specific near-infrared fluorescence probes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new series of dicyanoisophorone fluorophores with different donor groups have been synthesized and their photophysical properties have been studied. • The fluorescent probe with p -dimethylamine and o -hydroxyl group exhibited the best sensing ability to human serum albumin. • The sensing mechanism was studied by Job's plot, replacement experiment, and molecular docking. • The fluorescent probe is capable of determination of albumin in real serum and urine samples. It is urgently needed to develop NIR-fluorescent probe for detection of human serum albumin (HSA) since the interference of short-wavelength-fluorescence from endogenous species in real serum and urine. However, most previous reports were located in the short-wavelength region (<600 nm). In this work, a series of dicyanoisophorone (DCO)-based fluorophores 1 – 4 with different donor groups have been designed and investigated. A systematic study of their photophysical properties has been carried out. Among these probes, 4 exhibited NIR emission with the highest fluorescence brightness and the most sensitive signal response to HSA. Further studies demonstrated that 4 could strongly bind into the DS1 pocket of HSA with a 1:1 ratio. Importantly, the method based on 4 has been proven to be capable of sensing HSA in real serum and urine samples. [ABSTRACT FROM AUTHOR]

Determination of albuminuria at the point-of-care can provide an early diagnosis and monitor the quality management of numerous diseases. Yet for most fluorescent probes, the detection accuracy is not reliable, since urine itself exhibits very strong endogenous fluorescence causing a considerable interference on response signal. We herein report a novel fluorescent probe DNC with an enhanced environmental sensitivity and red-shifted wavelength (> 600 nm) by enlarging its transition dipole moment. The DNC could selectively bind with drug sites of albumin, causing a significant fluorescence enhancement without the interference from urinary fluorescence. Based on this sensing approach, albuminuria could be directly diagnosed at the point-of-care by using a simple homemade test system (even by naked eyes) without complicate pretreatment of urine. [Display omitted] • A novel fluorescent probe enables determination of albuminuria at point-of-care. • This fluorescent probe can give red-emissive response to albumin without the interference from urinary fluorescence. • The A2-level and A3-level albuminuria can be discriminated by naked eyes using this probe. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel flavonoid probe is reported for fluorescence discrimination of HSA from BSA. • The sensing mechanism was studied by Job's plot, site-displacement experiment, and molecular docking. • The specific response to HSA was attributed to the albumin-induced restricted intramolecular rotation of flavonoid probe. Discrimination of human serum albumin (HSA) from bovine serum albumin (BSA) based on the fluorescence probe technique is still challenging due to similar chemical structures. In this work, a novel flavonoid-based fluorescent probe AF is reported for successful discrimination of HSA from BSA. The sensing performances of probe, including sensing dynamic, sensitivity and selectivity, have been carefully studied. Moreover, sensing mechanism was elucidated by Job's plot, displacement experiment, and molecular docking, suggesting that the specific response to HSA originated from the albumin-induced restricted intramolecular rotation (RIR) of probe. This work may provide a simple way for designing of novel probes for HSA with high selectivity. [ABSTRACT FROM AUTHOR]