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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]

The development of a fluorescent probe for pyriproxyfen (PPF) is crucial due to its potential threat to human health. However, the chemical inertness and low solubility of PPF present significant challenges for the detection of PPF in aqueous solutions using fluorescent probes. Herein, we have originally proposed a complex based on 2-(4-(dimethylamino)phenyl)−3-hydroxy-6,7-dimethoxy-4 H-chromen-4-one (HOF) and serum albumin (SA) as a dual-mode fluorescent probe, HOF@SA. This probe utilizes an indicator displacement assay (IDA) to release the dye HOF from the probe at low PPF concentrations (< 10 µM) and embeds the free dye HOF into the micelle of PPF at high concentrations (> 10 µM). This results in dual-mode fluorescent response characteristics for PPF: a turn-off response at low concentrations and a ratiometric response at high concentrations. An investigation of sensing behavior of HOF@SA for PPF detection exhibits rapid response (< 60 s), high sensitivity (LOD ∼4.7 ppb), high selectivity, and excellent visual detection capability (from cyan to yellow). Moreover, with the aid of a portable device, this method enables to analyze PPF in environmental and food samples. These results promote the advancement of a fluorescent probe approach for PPF analysis in environment and food. [Display omitted] • The first fluorescent probe HOF@SA for PPF with dual-mode fluorescent response. • HOF@SA exhibits rapid response, high sensitivity and selectivity, and excellent visual detection capability. • The sensing mechanism has been revealed by molecular docking and fluorescence lifetime. • HOF@SA enables portable detection of PPF in real environmental samples using a miniaturized device. [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]

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 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]

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]