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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]

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] • 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]

[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] • 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]