Optical molecular imaging with near-infrared (NIR) dyes provides a promising strategy for the visual detection of tumor tissues. However, conventional molecular probes often suffer from poor targeting specificity and low signal contrast during tumor detection. In this work, we developed a reactive oxygen species (ROS)-activated tumor-seeking probe (termed MB-PEG-Bio2 ) based on a multivalent biotin-targeting strategy. A bivalent biotin-targeting ligand was bonded to an ROS-responsive molecular scaffold to maximize receptor–ligand interactions, resulting in significantly stronger tumor affinity and selectivity of the probe. The optical signal of the proposed probe was initially masked and could be selectively activated by overexpressed ROS levels in the tumor microenvironment. This activation led to the specific release of the clinical dye methylene blue (MB), offering high-contrast NIR fluorescence and photoacoustic imaging signals for precise tumor visualization. MB-PEG-Bio2 demonstrated strong tumor selectivity, enabling the detection of tumors in different mice models, including accurate identification of small tumors (∼3 mm). Consequently, the probe could delineate tumor boundaries during fluorescence-guided surgery, significantly reducing postoperative tumor recurrence.

In this study, a colorimetric aptasensor was fabricated to determine β-lactoglobulin (β-LG) concentration in foods. A bimetallic MOFzyme, CuCo–metal–organic framework (CuCo-MOF), was synthesized via a facile methodology to catalyze the colorimetric reaction of H2O2 and tetramethyl benzidine (TMB). Subsequently, the CuCo-MOF was combined with the β-LG aptamer to form a specific probe, i.e., CuCo-MOF-aptamer, which was modified on medium-speed qualitative filter paper to fabricate a colorimetric aptasensor platform. The presence of β-LG inhibited the catalytic activity of CuCo-MOF, and the degree of coloration was inversely proportional to β-LG concentration. The color image was procured using a smartphone and imported into ImageJ software to analyze the R/Y value for quantitative determination of β-LG via red, green, blue (RGB) colorimetric signal. The limit of detection (LOD) for β-LG was 0.102 mg/L, and the linear range for the optimized assay was 0.39–1250 mg/L, obtained after a series of optimizations. The commercial enzyme-linked immunosorbent assay (ELISA) test results indicated the suitability of this method for real-food sample (milk and infant formula) analysis. The developed paper-based RGB colorimetric aptasensor emerges as a user-friendly and economical assay for high-throughput, visual, and accurate determination of β-LG in foods.

Malononitrile is a very important chemical material and has wide application fields in production of medicines, pesticides, and extraction of gold. However, its nonnegligible hypertoxicity inspired researchers to develop more efficient analysis techniques to sensitively and selectively detect malononitrile. Nopinone derivatives initiated by our research group have been developed as a class of organic fluorescent chemosensors for identifying multiple analytes in recent years. Different heterocyclic compounds based on nopinone were designed and synthesized to be applied in the fields of environmental analysis, food detection and bioimaging. Nevertheless, the comparison research on the optical properties of fluorescent compounds containing the nopinyl matrix with other structural analogs including alkyl, cyclohexyl and phenyl groups was deficient. Herein, four 4-(1H-imidazol-2-yl)benzaldehyde-based ratiometric fluorescent chemosensors based on o-dimethyl cyclohexyl, phenyl and nopinyl units for recognizing malononitrile were designed and developed, and their differences in the optical properties and detection performances were investigated by using spectral analysis combined with theoretical calculations. Moreover, the nopinone-based 4-(1H-imidazol-2-yl)benzaldehyde fluorescent chemosensor NMZQ was successfully applied in the dual channel fluorescence bioimaging of malononitrile in living HeLa cells and zebrafish, which attributed to its outstanding spectral property and detection performance.

Hydrazine (N2H4) is an extremely important reagent in industrial fields, but it can cause huge damage to human being and environment. Herein, a novel coumarin-based fluorescent probe CHY was designed and developed for hydrazine detection. The probe CHY exhibited no remarkable fluorescence in solution and showed an obvious fluorescence enhancement response toward hydrazine. Moreover, it could detect hydrazine with excellent selectivity, strong anti-interference and high sensitivity within a wide range of pH from 5 to 9. The limit of detection (LOD) of CHY for hydrazine was calculated to be 2.4 x 10-8 M, which was lower than the standard advised by the Environmental Protection Agency (3.12 x 10-7 M). The detection mechanism of CHY toward hydrazine was investigated by density functional theory (DFT) calculations and 1H NMR titration. In addition, CHY was successfully utilized to monitor hydrazine in real water samples, and has the capability of imaging hydrazine in living zebrafish.

Hydrogen sulfide (H2S) is closely related to food safety, environmental pollution, and human health. Herein, a fluorescent turn-on responsive probe, 3-(2,4-dinitrophenoxy)-7-(4-(diphenylamino)phenyl)-2-(furan-2-yl)-4H-chromen-4-one (DPF-NP), with a large Stokes shift (210 nm) based on the natural product flavonol was synthesized for detecting H2S. DPF-NP showed high selectivity and sensitivity, a low limit of detection (96 nM), and fast response (3 min) for detecting H2S. After reacting with H2S, DPF-NP exhibited strong orange fluorescence (590 nm), attributed to the excited-state intramolecular proton transfer (ESIPT) effect. In addition, the probe DPF-NP could quantitatively monitor H2S in environmental water and food samples (red wine, beer, eggs, milk, and sour bamboo shoots). Furthermore, DPF-NP has been successful in imaging H2S in vegetable tissues, living cells, and zebrafish. Therefore, this work offers an encouraging method for monitoring H2S in environmental pollution, food quality safety, and living systems.

Hydrogen sulfide (H2S) has comprehensive contributions to maintaining the normal operation and stability of organisms, and it also occurs in the wastewater environment and is related to the deterioration of foodstuffs. Therefore, developing high-sensitive detection techniques for tracing H2S is promising and meaningful. Inspired by this, a novel nopinone-based fluorescent probe NPS for the recognition of H2S was designed and synthesized with excellent sensitivity, low limit of detection (79 nM), good selectivity, and wide pH range (5-9). NPS could emit strong yellow fluorescence and its emission intensity showed a remarkable augmentation at 520 nm upon the supplement of H2S. Furthermore, the recognition mechanism of NPS for H2S was verified by the HRMS analysis, 1H NMR spectra titration, and DFT computation. What is more, NPS also had broad applications in the monitoring of real water samples, red wine, beer, and eggs samples, which showed its development prospect and value in environmental pollution, foodstuffs quality analysis fields. NPS also was applied to monitor trace exogenous H2S and bioimaging in living cells and zebrafish.

Biothiols (GSH, Hcy, Cys) are important active sulfur substances in biological systems and widely participate in various physiological processes. The three kinds of biothiols have similar chemical structures, including the sulfhydryl group (-SH) and an amino group (-NH2), so distinguishing two or more of them simultaneously is an important challenge. Herein, a nopinone-based fluorescent probe 3-(3-((4-nitrobenzoxadiazole vinyl) nopinyl difluoride (NF-NBD) was designed to distinguish GSH and Hcy/Cys by generating different fluorescence channels with a single excitation wavelength. The nitrobenzodioxazole (NBD) was introduced in the fluorescent probe by ether bounds that can quench fluorescence and selectively discriminate GSH and Hcy/Cys. After reacting with GSH and Hcy/Cys, NF-NBD exhibited strong fluorescence (green for GSH and yellow for Hcy/Cys). NF-NBD displayed a wide linear range, low detection limit, a rapid response time, and superior selectivity for biothiols. Furthermore, NF-NBD was applied to image and distinguish different biothiols in living cells and zebrafish via different fluorescence signals at a single excitation wavelength.

Formaldehyde (FA) is an environmental toxin and widely used in building and decorating materials, which is listed as a class 1 carcinogen. Silver ion (Ag+) has a beneficial bactericidal effect, while it can also cause silver poisoning and skin damage. Therefore, developing a quantitative detection technique for formaldehyde and Ag+ is necessary. In this study, a novel difunctional fluorescent probe (DBP) was designed and synthesized based on the natural product dehydroabietic acid, which could selectively detect formaldehyde and Ag+ through "turn-on" and "turn-off" fluorescence response, respectively. The probe DBP performed satisfactory nanomolar-level detection limit to formaldehyde (38 nM) and Ag+ (19 nM) in ethanol/PBS (3/7, v/v, pH = 7.4) solution. Furthermore, DBP could effectively recognize formaldehyde and Ag+ within a short response time (FA: 15 min, Ag+: 100 s) and a wide pH range (5-10). The sensing mechanisms of DBP to FA and Ag+ were well verified by 1H NMR titration, ESI-MS, DFT computation, and Job's plot analysis. What is more, the applications in bioimaging were carried out in MCF-7 cells and living zebrafish. Besides, the probe DBP was successfully applied in detecting FA and Ag+ in actual food and water samples, and the DBP-loaded filter paper was prepared for convenient tracking gaseous FA and Ag+.

L-Cysteine (Cys) plays a vital part in the food industry and biological processes. Herein, a novel ratiometric fluorescent probe NFA with aggregation-induced emission (AIE) property was developed to discriminate Cys from Hcy and GSH. The probe showed a ratiometric fluorescence response to Cys with the emission wavelength shifted from 450 nm to 495 nm. Probe NFA possessed good advantages in the detection of Cys including wide linear range (0-100 mu M), low detection limit (0.21 mu M), and rapid response time (within 2 min). Compared with previous reports, this is the first ratiometric probe that achieves the quantitative detection of Cys in different food samples in real-time (cabbage, bamboo shoots, lotus root, garlic, apple, pear, milk powder, and liquid milk). Moreover, NFA is successfully applied for ratiometric image endogenous and exogenous Cys in HeLa cells and zebrafish which demonstrated its practical biological application.

Al3+ is commonly utilized in daily life, however, the excessive accumulation of Al3+ within organisms can result in severe health problems. Herein, a highly efficient fluorescent probe EC-HTC for Al3+ was synthesized through chemical modification of ethyl cellulose. This probe exhibited a significant fluorescence enhancement response to Al3+, and it interestingly also possessed an obvious aggregation-induced emission (AIE) effect. The detection limit of probe EC-HTC for Al3+ was as low as 0.23 μM, and its pH usage range was as wide as 5-10. The complexation ratio of EC-HTC with Al3+ was determined to be 1:1 based on Job's plot, which was further confirmed by 1H NMR titration and HRMS analysis. Moreover, the probe EC-HTC was successfully employed for the determination of Al3+ in environmental and food samples. In addition, the probe EC-HTC compositing PS (polystyrene) electrostatic spun fiber membranes EHP with high specific surface area were prepared to achieve the rapid and portable detection of Al3+.

Viscosity and pH are two crucial microenvironment parameters, and their abnormal fluctuations at the cellular level can act as key indicators of various diseases diagnosis. Considering that the traditional viscosity/pH meters cannot work in the cellular environment, developing some viscosity/pH-sensitive fluorescent probes is urgently demanded. Herein, a novel dual-functional camphor-based fluorescent probe PN-SP for viscosity and pH detection was constructed based on spiropyran open/closed-ring switching strategy. PN-SP exhibited an intense green emission in response to alkaline pH while a bright red fluorescence was observed in high-viscosity media, which could avoid some problems caused by the use of multiple probes such as cross-talk spectrum and different localizations. The sensing performances of PN-SP were also demonstrated for monitoring viscosity and pH fluctuations in living HeLa cells by means of different emisson channels. Therefore, we believed that this work will provide guidance for designing some dual-functional fluorescent probes.

L-Cysteine (Cys) plays an important role in the food industry and the physiological processes. Herein, a new fluorescent turn-on probe 6-(4-(Diphenylamino)phenyl)-2-(furan-2-yl)-3-hydroxychromone acrylate (DDPF) with AIE property based on flavonol was developed for rapidly detecting Cys. This probe displayed a significantly enhanced fluorescence response to Cys over other various competing analytes such as amino acids, cations, and anions. Probe DDPF possesses some good advantages in the detection of Cys including large Stokes shift (195 nm), low detection limit (97.6 nM), wide pH range (3-8), and fast response time (50 s). In addition, DDPF was also employed for the quantitative determination of trace Cysteine in dairy product samples, such as milk, milk powder, cheese, and yogurt. Moreover, this probe had good biocompatibility and could visualize endogenous and exogenous Cys in the living cells. Furthermore, it could be successfully applied for fluorescence imaging Cys in zebrafish.

A new colorimetric and fluorescent turn-on probe named 2,4-bis(camphor-3-methylene)phenylacrylate (BCP-Cys) was designed for highly sensitive and specific monitoring of cysteine (Cys). The probe BCP-Cys was strategically constructed by employing a new bis-camphor-derived scaffold (BCP-OH) as the fluorophore and an acrylate group as the recognition site and fluorescence quencher. The acrylate group of BCP-Cys could be exclusively cleaved by Cys and release the fluorophore BCP-OH, thereby causing a significantly enhanced red fluorescence and a naked-eye colorimetric change from colorless to yellow. The probe BCP-Cys exhibited promising sensing performances for Cys including large Stokes shift (184 nm), fast response time (<1 min), wide linear range (0-100 nM), and low detection limit (0.0728 μM). Moreover, the probe BCP-Cys could be utilized as a powerful tool for real-time determination of Cys levels within different food samples, such as onion, cabbage, broccoli, garlic, cauliflower, and bamboo sprout. In addition, this probe was also capable of imaging endogenous and exogenous Cys in living cells.

As a tremendously noxious and extensively utilized chemical reagent, hydrazine (N2H4) has become a serious threat to ecosystem and human health. Thus, it is desirable to exploit an efficient method for real-time tracking of hydrazine. Here, a novel ratiometric fluorescent probe PBQ-AB for hydrazine was rationally constructed from isolongifolanone. This probe displayed an extremely large Stokes shift of 230 nm and could selectively recognize hydrazine in the presence of other competitive species within an extremely short time ( 40 s). PBQ-AB also displayed some fascinating merits in the detection of hydrazine, including low detection limit (48 nM), wide pH range (5-12), excellent photostability (>240 min), and well-resolved emission wavelength shift (148 nm). Moreover, this probe was utilized to fabricate a ready-to-use electrospinning nanofibrous membrane for convenient detection of hydrazine vapor by virtue of smartphone. Furthermore, PBQ-AB was capable of determining hydrazine contaminant in environmental soil and water samples. Additionally, its favorable performance for detecting hydrazine was successfully demonstrated in live HeLa cells as well as in live Arabidopsis thaliana tissues, manifesting its promising application for labeling hydrazine in living systems. Therefore, we believed that this probe has great potential in environmental analysis and health supervision.

Cyanide anion is a ubiquitous chemical substance in the ecosystem, however, human daily life is severely threatened by its toxicity at any time. In this paper, a novel colorimetric and turn-on chemosensor 4-(4(2,2-difluoro-6-methyl-2H-1,3,2-dioxaborinin-4-yl)buta-1,3-dien-1-yl)-N,N-dimethylaniline (NBF) for detecting cyanide anion was synthesized based on the 4-(dimethylamino)cinnamaldehyde and beta-diketone difluoroboron complex. This fluorescent probe exhibited excellent spectroscopy properties such as large stokes shift, long emission wavelength, and good sensitivity. The detection limit of NBF towards cyanide ion was determined as low as 2.23 mu M. Additionally, the detection mechanism towards cyanide ion was confirmed to be the nucleophilic addition interaction by high resolution mass spectrum (HRMS), H-1 Nuclear Magnetic Resonance (NMR) titration, and quantum chemistry theory calculation. In addition, the probe NBF had been successfully utilized in detecting cyanide ions in water and food samples as well as imaging in the biological system, which broadened its practical application prospects. (C) 2022 Elsevier B.V. All rights reserved.

Cellulose is the most abundant natural polymer with good biodegradability and biocompatibility. In this paper, a novel fluorescent probe DAC-SD-NA for aluminum (Al3+ ) detection is successfully synthesized based on dialdehyde cellulose (DAC). DAC-SD-NA exhibited a remarkable "turn-on" fluorescence response to Al3+ in a wide pH range, and the fluorescence color of DAC-SD-NA solution turned from colorless to bright blue at the presence of Al3+ . The detection limit for Al3+ is computed to be 6.06×10-7 m. The reaction mechanism of DAC-SD-NA towards Al3+ is confirmed by Job's plot, X-ray photoelectron spectroscopy, and density functional theory (DFT) calculations. In view of DAC-SD-NA exhibited good sensitivity and selectivity, it is applied to detect Al3+ in real water. What's more, DAC-SD-NA-loaded fluorescent hydrogel can serve as a convenient tool for the detection of Al3+ .

Cyanide (CN-) is one of the most lethal chemical substance and exists in the organisms and environment. Due to the CN- and CN- containing chemicals being widely applied in industrial fields and threatening human health, the sensitive and selective detection techniques towards CN are still essential. Based on this, a "turn-on" fluorescent probe 2-(4-(5,5-dimethyl-4,5,6,7-tetrahydro-3H-4,6-methanobenzo[d]imidazol-2-yl)styryl)-3-ethylbenzo[d]thiazol-3-ium iodide (NCy) was designed and synthesized for monitoring CN- NCy had a distinguishable color change towards CN- from colorless to yellow under 365 nm UV-light. NCy possessed the merits including low LOD (75 nM), good selectivity, and wide suitable pH range (4-10). The sensing mechanism of NCy towards CN- was proved by HRMS, H-1 NMR titration and DFT analysis. Furthermore, the probe NCy was successfully utilized in detecting endogenous CN- in three food samples (green potato, cassava, and bitter almond) quantitatively. In bioimaging aspect, NCy was also successfully applied in detecting the exogenous CN- in living zebrafish.

A simple yet highly effective camphor-derived fluorescent probe named 3-(anthracen-9-ylmethylene)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one oxime (ATHO) was developed based on an oxime recognition receptor and anthracene fluorophore. The probe ATHO exhibited a remarkably enhanced fluorescence response to HClO (∼7.2 fold). Meanwhile, this probe exhibited a low detection limit (0.118 μM), ultrafast response time (within seconds), excellent photostability (>260 min), wide linear range (0-180 μM), low probe concentration (2 μM), and high selectivity toward HClO over various interfering species. The sensing mechanism of the probe ATHO for HClO was supported by HRMS analysis and theoretical calculations. Furthermore, the probe ATHO was utilized to quantitatively determine HClO levels in environmental water samples. Additionally, the biological imaging of the probe ATHO for exogenous and endogenous HClO was successfully demonstrated in vitro and in vivo.

α-和β-蒎烯是天然松节油的主要成分,具有良好的抑菌、杀虫、抗炎等生物活性,广泛应用于香精、香料、化妆品和医药等领域.蒎烯属于双环单萜类化合物,具有独特的双环结构和碳碳双键,因而化学性质特别活泼.通过烯烃双键加成或环外甲基氧化等反应引入新的官能团,得到双环结构蒎烷基衍生物;通过对烯烃双键的开环氧化或异构化等反应,可以打开桥环分子,形成四元或六元环衍生物,从而制备结构丰富的功能性化合物.目前,以天然、可再生的蒎烯为原料合成具有生物活性高、应用性强的新型蒎烷基衍生物已成为蒎烯深加工研究热点.总结了蒎烯生物活性及化学性质,综述了近年来基于蒎烯结构的蒎烯基嘧啶类衍生物、蒎烯基硫脲类衍生物、蒎烯基噻唑类衍生物、蒎烯基吡唑酰胺衍生物、蒎烯基磺酸衍生物、蒎烯基取代烷衍生物、桃金娘烯醛衍生物、马鞭草烯酮衍生物等双环结构蒎烷基衍生物,以及蒎酸衍生物、二氢枯铭酸衍生物、蒎酮酸衍生物、对孟烷胺衍生物和松油烯马来酸酐衍生物等开环蒎烷基衍生物的合成及其在抑菌、杀虫、抗肿瘤、除草、消炎和降糖等活性研究进展,探讨了化合物结构与活性关系,提出了当前存在问题并展望了未来的发展方向.

Hydrazine is extremely toxic and causes severe harm to human body. Herein, a novel fluorescent probe 4-oxo-2-styryl-4H-chromen-3-yl thiophene-2-carboxylate (FHT) was synthesized for detecting hydrazine by using natural cinnamaldehyde as starting material. This probe exhibited significantly enhanced fluorescence response towards hydrazine over various common metal ions, anions, and amine compounds. The detection limit of probe FHT for hydrazine was as low as 0.14 μmol·L–1, significantly lower than that of the threshold value of 0.312 μmol·L–1, imposed by the Environmental Protection Agency. Moreover, the proposed probe was able to detect hydrazine within wide pH (5–10) and linear detection ranges (0–110 μmol·L–1). This probe was employed for determining trace hydrazine in different environmental water samples. The probe FHT-loaded filter paper strips were able to conveniently detect hydrazine of low concentration through distinct naked-eye and fluorescent color changes. Importantly, the probe FHT with low cytotoxicity was successfully applied to visualize hydrazine in living Hela cells and zebrafish.