A fluorescent probe generating in situ the reactive species for rapid and selective detection of mustard gas.

Sulfur mustard (SM) is an important chemical warfare agent (CWA) and has been used frequently in various conflicts. It is important to develop a facile, rapid, sensitive and selective detection method for SM. In this work, we constructed a novel fluorescent probe PCS capable of generating active sensing species for rapid and selective detection of SM and its simulant CEES (2-chloroethyl ethyl sulfide). PCS exhibits excellent chemical and photostability and can generate reactive species in situ for rapid (within 90 s, at 60 °C) and selective detection of SM and CEES in solution with high sensitivity (∼nM level). Moreover, PCS could enable the detection of mustards in situ. A test strip with PCS and KOH was prepared and realized the sensitive and selective detection of CEES in the gas phase. In addition, the PCS probe can realize facile and rapid detection of CEES-contaminated surfaces by spraying its sensing system (ethanol solution containing PCS and KOH). The sensing mechanism was well demonstrated through the separation and characterization of the sensing product.

Bifunctional Fluorescent Probes for the Detection of Mustard Gas and Phosgene.

Mustard gas [sulfur mustard (SM)] and phosgene are the most frequently used chemical warfare agents (CWAs), which pose a serious threat to human health and national security, and their rapid and accurate detection is essential to respond to terrorist attacks and industrial accidents. Herein, we developed a fluorescent probe with o-hydroxythioketone as two sensing sites, AQso, which can detect and distinguish mustard gas and phosgene. The dual-sensing-site probe AQso reacts with mustard gas to form a cyclic product with high sensitivity [limit of detection (LOD) = 70 nM] and is highly selective to SM over phosgene, SM analogues, active alkylhalides, acylhalides, and nerve agent mimics, in ethanol solutions. When encountering phosgene, AQso rapidly converts to cyclic carbonate, which is sensitive (LOD = 14 nM) and highly selective. Their sensing mechanisms of AQso to mustard gas and phosgene were well demonstrated by separation and characterization of the sensing products. Furthermore, a facile test strip with the probe was prepared to distinguish 2-chloroethyl ethyl sulfide (CEES) and phosgene in the gas phase by different fluorescence colors and response rates. Not using the complicated instrument, the qualitative and quantitative detection of CEES or phosgene can be achieved only by measuring the red-green-blue (RGB) channel intensity of the test strip after being exposed to CEES or phosgene gas by the smartphone with an RGB color application.

Real-time, sensitive and simultaneous detection of GSH and Cys/Hcy by 8-substituted phenylselenium BODIPYs: a structure-activity relationship.

Real-time and sensitive detection of biothiols is the key to biomedical research and clinical diagnosis. It is necessary to develop a highly sensitive and selective fluorescent probe for the detection of biothiols. In this paper, we have developed a series of meso-arylselenium BODIPY probes for the rapid and sensitive detection of biothiols and the dual-channel discrimination of GSH and Cys/Hcy. A structure-activity relationship was established from five p-substituted phenylselenium (R = NO2, F, H, OCH3 or N(CH2CH2)2O) BODIPYs. Compared with most reported fluorescent probes, such as meso-BODIPY sulfur ethers, these probes display much lower LODs (∼nM levels) and more rapid responses, which are ascribed to the higher fluorescence efficiencies of the sensing products (Φf = 0.48 for GSH, 0.18 for Cys and 0.14 for Hcy) and the introduction of arylselenium, which is more active than arylthiol. Among them, the best sensing performance is that of probe 2a (R = NO2); therefore, a structure-activity relationship of these fluorescent probes was also obtained. The excellent sensing performance was further revealed in the detection of GSH and Cys/Hcy in live cells.

An 8-arylselenium BODIPY fluorescent probe for rapid and sensitive discrimination of biothiols in living cells.

By introducing 8-arylselenium as the active group, a BODIPY fluorescent probe ASeBD was constructed for rapid and sensitive detection and dual-channel discrimination of GSH and Cys/Hcy in solution and in living cells, and its mechanism was demonstrated.

Quinoline-2-thione-based fluorescent probes for selective and sensitive detections of mustard gas and its analogues.

Sulfur mustard (SM, also called as mustard gas (HD)) is a persistent and highly toxic gas used as chemical weapon in wars and military conflicts. Moreover, owing to its simple structure and easy synthesis, it is the most likely chemical agent used by terrorists. For this reason, it is vital important to develop a facile, rapid and reliable detection system for SM. In this paper, we have developed four quinoline-2-thiones as fluorescent probes, 2a-2d, for the detection of SM and its analogues, half sulfur mustard (CEES) and a nitrogen mustard NH1. In the presence of KOH, these quinoline-2-thiones deprotonated to quinoline-2-thiophenol anions, which react with SM and its analogues rapidly to form quinoline-2-thiethers with highly efficient fluorescence, giving turn-on fluorescence response. The sensing products with CEES were isolated and fully characterized, thereby, the sensing mechanism was firmly established. The fluorescent probes with 4-trifluoromethyl group, 2b and 2d, exhibit rapid response to SM, CEES and NH1 (within 1 min at 60 °C for CEES and NH1), high sensitivity (limit of detection, 50 nM for SM and 20 nM for NH1) and high selectivity. Furthermore, polymer film test strips were fabricated with probe-embedded poly(ethylene oxide) for the detection of CEES vapor. These test strips displayed a rapid response (<4 min) to gaseous CEES with high sensitivity (0.2 ppm) and high selectivity. These results show that fluorescent probes 2b and 2d have a good application prospect in the field detection of mustard gas.

Sensitive and selective detections of mustard gas and its analogues by 4-mercaptocoumarins as fluorescent chemosensors in both solutions and gas phase.

Mustard gas has been used as a chemical warfare agent for a century, and is the most likely chemical weapon used in wars or by terrorists. Thus, it is important to develop a facile, rapid and highly selective method for the detection of mustard gas. In this paper, two fluorescent probe molecules, 4-mercaptocoumarins, have been developed for rapid and sensitive detections of SM and its analogues (CEES and NH1) in both solutions and gas phase. The sensing reaction is a nucleophilic addition at three-membered hetercyclic sulfonium/ammonium formed from SM, CEES/NH1 in ethanol. Two fluorescent probes (4-mercaptocoumarins, ArSH) in ethanol deprotonate to form thiophenol anions (ArS-) resulting from their low pKa values (3.2-3.4), and the nucleophilic addition of the anion ArS- generates the corresponding thioethers, giving a turn-on fluorescence response. The thiophenol anion can fast sense SM, CEES and NH1 (within 1-4 min) with high sensitivity (~nM level) at 60 °C, and high selectivity through adding a tertiary amine, and two probes exhibit excellent chemical and photostability in detection systems. Furthermore, a facile test strip with the sensor was fabricated for the detection of CEES vapor with rapid response (3 min), high sensitivity (9 ppb) and high selectivity.

Rapid and sensitive detection of nitric oxide by a BODIPY-based fluorescent probe in live cells: glutathione effects.

Nitric oxide (NO) is an important signaling molecule involved in various physiological and pathological processes. The effects of NO depend on its concentration, and the spatial and temporal constraints of the cell microenvironment. Meanwhile, NO can react with some biomolecules such as biothiols, leading to a short biological lifetime. Thus, it is very crucial to establish a real-time visualization method for monitoring NO levels. In this work, we have developed a fluorescent probe, RBA, for NO, with a 3-extended BODIPY as a fluorophore and a secondary amine as the active site. The probe RBA can quickly sense NO (∼10 s) in aerobic solutions to generate a fluorescent N-nitrosamine (RBA-NO, Φf = 0.87) due to blocking of the photoinduced electron transfer (PET) process from the secondary amine to the BODIPY core. This sensing reaction displays high sensitivity (LOD = 10 nM) and high selectivity for NO over relevant analytes except some reducing reagents including biothiols, and a remarkable interference effect is observed ascribed to a competitive reaction with biothiols. Furthermore, the exo- and endogenous detection of NO in live cells and zebra fish was achieved, and it was demonstrated that glutathione (GSH) weakens drastically the fluorescence response by cell-imaging experiments. These results imply that the colorimetric and fluorescence response of the chemosensor for NO depends on the levels of both NO and GSH in environments.

Sensitive and Selective Detection of Phosgene, Diphosgene, and Triphosgene by a 3,4-Diaminonaphthalimide in Solutions and the Gas Phase.

Phosgene and its substitutes, diphosgene and triphosgene, are highly toxic and widely used chemicals, so it is necessary to investigate their reactivity and develop facile, sensitive, and specific methods for detecting them. In this work, we have developed a new 1,8-naphthalimide-based fluorescent chemosensor, Phos-2, which exhibits high sensitivity (detection limits: 0.2-0.7 nm), high selectivity to phosgene and its substitutes over nitric oxide (NO), various acyl chlorides, and nerve agent mimics in solutions. Based on investigation of the reaction kinetics of Phos-2 with phosgene and its substitutes, a two-step sensing mechanism was clarified. The second-order rate constants (k2 ) of Phos-2 reveal that the relative rate constants of phosgene, diphosgene, and triphosgene are 40:4:1. Moreover, a Phos-2 test paper has been fabricated as a low-cost, sensitive (≈5 ppm from observation by the naked eye or 0.1 ppm from a measurement), and efficient method for visual detection of a low concentration of phosgene in the gas phase.

Fluorescent Chemosensor for Selective Detection of Phosgene in Solutions and in Gas Phase.

The detection of highly toxic chemicals in a convenient, fast, and reliable manner is essential for coping with serious threats to humankind and public security caused by unexpected terrorist attacks and industrial accidents. In this paper, a highly selective fluorescent probe has been constructed through o-phenylenediamine covalently linking to coumarin (o-Pac), which can respond to phosgene in turn-on fluorescence mode. The response time is less than 0.5 min and the detection limit is as low as 3 nM in solutions. More importantly, the sensor exhibits good selectivity to phosgene over triphosgene and various acyl chlorides. Furthermore, a portable test paper has been fabricated with polystyrene membrane containing o-Pac for real-time selective monitoring of phosgene in gas phase.

BODIPY-Based Fluorescent Sensor for the Recognization of Phosgene in Solutions and in Gas Phase.

As a highly toxic and widely used chemical, phosgene has become a serious threat to humankind and public security because of its potential use by terrorists and unexpected release during industrial accidents. For this reason, it is an urgent need to develop facile, fast, and selective detection methods of phosgene. In this Article, we have constructed a highly selective fluorescent sensor o-Pab for phosgene with a BODIPY unit as a fluorophore and o-phenylenediamine as a reactive site. The sensor o-Pab exhibits rapid response (∼15 s) in both colorimetric and turn-on fluorescence modes, high selectivity for phosgene over nerve agent mimics and various acyl chlorides and a low detection limit (2.7 nM) in solutions. In contrast to most undistinguishable sensors reported, o-Pab can react with phosgene but not with its substitutes, triphosgene and biphosgene. The excellent discrimination of o-Pab has been demonstrated to be due to the difference in highly reactive and bifunctional phosgene relative to its substitutes. Furthermore, a facile testing paper has been fabricated with poly(ethylene oxide) immobilizing o-Pab on a filter paper for real-time selective monitoring of phosgene in gaseous phase.

A ratiometric fluorescent chemosensor for selective and visual detection of phosgene in solutions and in the gas phase.

A ratiometric fluorescent chemosensor, Phos-1, was constructed with 4,5-diaminonaphthalimide as a fluorophore for selective and visual detection of phosgene. The sensing mechanism was demonstrated to be the phosgene molecule acylating both amine groups of Phos-1. A test paper with Phos-1 was fabricated for facile, selective and visual detection of phosgene gas.

Red fluorescent probes based on a Bodipy analogue for selective and sensitive detection of selenols in solutions and in living systems.

Selenocysteine (Sec), which is a biological selenol incorporated into selenoproteins specifically, plays vital roles in physiological processes and cancer treatment. However, there are limited fluorescent probes for selective detection of Sec and in only one case is a near-infrared (IR) fluorescent probe applied in biological imaging of Sec in living animals. In this work, we have synthesized a new fluorophore, boron-dibenzopyrromethene (B-Bodipy), with an absorption maximum at 650-660 nm, and constructed two deep red fluorescent probes, Sel-p1 and Sel-p2, which are two ethers composed of a 2,4-dinitrobenzenoxy and B-Bodipy moiety. Experiments in solution show that the two probes can react effectively with selenols to release the fluorophore via aromatic nucleophilic substitution (SNAr), with a low limit of detection (16 nM and 9 nM), high selectivity and excellent photostability. The potential application for the detection of Sec in cells has been demonstrated by cell imaging experiments of Sel-p2, including detection of exogenous Sec and selenite-induced Sec in living cells. Furthermore, Sel-p2 as a red fluorescent probe can achieve the detection of Sec in animals by mice imaging experiments.

Ratiometric two-photon fluorescent probes for mitochondrial hydrogen sulfide in living cells.

Hydrogen sulfide (H2S) is an important signaling molecule with diverse biological roles. Various fluorescent probes for H2S with biological application have been developed. However, two-photon ratiometric imaging of mitochondrial H2S is scarce. In this paper, we report two ratiometric two-photon probes, AcHS-1 and AcHS-2, which employ 4-amino-1,8-naphthalimide as the fluorophore and 4-azidobenzyl carbamate as the H2S response site. These probes exhibit high selectivity toward H2S over biothiols and other reactive species, low detection limits of 50-85 nM, low cytotoxicity, and high stability under physiological conditions. Furthermore, through cell imaging with one-photon and two-photon microscopy, MCF-7 cells incubated with two probes show a marked change in emission color from blue to green in response to H2S. Cell images costraining with a mitochondrial dye reveal that AcHS-2 is a mitochondria-specific two-photon probe for H2S. These results show that AcHS-2 may find useful applications in biological research such as tracking mitochondrial H2S in living biological specimens.

Quinolinium-based fluorescent probes for the detection of thiophenols in environmental samples and living cells.

A new type of fluorescent probes for thiophenols, 6HQM-DNP and 7HQM-DNP, containing 6- or 7-hydroxy quinonlinium as fluorophore and 2,4-dinitrophenoxy (DNP) as nucleophilic recognition unit were constructed. As ethers, these non-fluorescent probe molecules can release the corresponding fluorescent quinolinium (6HQM and 7HQM) through aromatic nucleophilic substitution (S(N)Ar) by thiolate anions from thiophenols. The sensing reaction is highly sensitive (detection limit of 8 nM for 7HQM-DNP) and highly selective to thiophenols over aliphatic thiols and other nucleophiles under neutral conditions (pH 7.3). The probes respond rapidly to thiophenols, with second-order rate constants k=45 M(-1) s(-1) for 7HQM-DNP and 24 M(-1) s(-1) for 6HQM-DNP. Furthermore, the selective detection of thiophenols in living cells by 7HQM-DNP was demonstrated by confocal fluorescence imaging. In addition, these quinolinium salts show excellent chemical and thermal stability. In conclusion, this type of probes may find use in the detection of thiophenols in environmental samples and biosystems.

Invaginated Pancreaticojejunostomy via the Space Behind the Root of Superior Mesenteric Vessels.

BACKGROUND: This study was to explore a safe and effective procedure to prevent pancreatic fistula (PF) after pancreaticoduodenectomy (PD). METHODS: Forty-three modified PD with pancreaticojejunostomy by direct invagination of the pancreas to the jejunum that was brought up via the space behind the root of superior mesenteric vessel were performed between January 2003 and June 2006, and were compared to the fifty-six conventional PD (Child' method). RESULTS: There was no pancreatic fistula after PD in the modified group. Two cases developed biliary fistula that were successfully treated with complete drainage for 2 to 3 weeks; 2 cases abdominal infection managed with anti-infection and completely drainage; 4 cases stress ulcer cured with Losec and coagulant. Three cases in the Child group developed PF of different severities, with amylase level > 9000 U/L in the abdominal drainage fluid. Two of the PF were treated with Stilamin, parenteral nutrition, fasting and completely drainage and cured after 21 to 32 days. The other 82-year-old patient died. Other complications had no significant difference between the two groups (P > 0.05). CONCLUSIONS: The modified PD can effectively prevent PF and is a safe and effective procedure for periampullary neoplasm. Further studies of its clinical use are warranted.

Extended local resection for treatment of periampullary carcinoma of vater.

BACKGROUND: The trauma caused by pancreatoduodenectomy for periampullary carcinoma of vater is often severe and extensive. The purpose of this study was to evaluate the effect of extended local resection in the treatment of periampullary carcinoma of vater. METHODS: The extra-hepaticobiliary tract, the confluence of the pancreatic and biliary duct, vater ampulla and duodenal papilla were resected en bloc in 8 patients with periampullary carcinoma from 1995 to 1998. RESULTS: One patient died perioperatively. Duodenal obstruction developed postoperatively in one of 7 survived patients and was relieved after reoperation. All the 7 patients were followed up for more than 6 months without recurrence. CONCLUSION: Extended local resection fulfils the task of radical treatment of periampullary malignancy.

Surgical treatment for uncinate process carcinoma of the pancreas.

OBJECTIVES: To analyze the clinical features of uncinate process carcinoma of the pancreas and to improve the resection rate. METHODS: From January 1990 to June 1999, 10 patients with pancreas uncinate process carcinoma received Whipple's operation. Portal vein (PV) resection and reanastomosis were performed in 5 patients, and the resected length varied from 2.0 to 4.2 cm. Two patients underwent PV lateral wall partial resection. RESULTS: Among the 7 patients undergoing PV resection, 1 died of hepatic failure 3 days after operation. One patient suffered from postoperative chylous ascites. These 6 patients survived 13 to 29 months postoperatively. Among the 3 patients without PV resection, 2 survived 13 months and 14 months respectively. One patient was alive by the end of follow-up for 11.5 months postoperatively. CONCLUSION: Although uncinate process carcinoma of the pancreas has a tendency to invade the adjacent PV and superior mesentery vein, it should not be simply regarded as a contraindication of radical resection.