RESUMO
Drug-Facilitated Sexual Assault (DFSA) is a problem of considerable dimensions on a global scale. Among the different compounds used in DFSA assaults, 4-hydroxybutyric acid (GHB) is one of the most elusive due to its physical and biological characteristics. Therefore, the development of real-time detection methods to detect GHB not only in drinks but also in urine is very important for personal and social security. Here, we report two new heteroditopic chemosensors capable of recognizing and detecting GHB in soft drinks, alcoholic beverages and synthetic urine. The compounds have two moieties: a trifluoroacetyl group and a thiourea, which are able to interact respectively with the hydroxyl and the carboxylic groups present in the GHB structure. In addition, the distance between these two groups has been optimized to allow a double interaction which guarantees the recognition even in very competitive media such as beverages or urine samples.
Assuntos
Oxibato de Sódio , Bebidas Alcoólicas/análise , Bebidas/análise , Bebidas Gaseificadas , Hidroxibutiratos/análiseRESUMO
A recompilation of applications of mesoporous silica nanoparticles in sensing from the last five years is presented. Its high potential, especially as hybrid materials combined with organic or bio-molecules, is shown. Adding to the multiplying effect of loading high amounts of the transducer into the pores, the selectivity attained by the interaction of the analyte with the layer decorating the material is described. Examples of the different methodologies are presented.
Assuntos
Nanopartículas , Dióxido de Silício , PorosidadeRESUMO
Silica mesoporous microparticles loaded with both rhodamine B fluorophore (S1) or hydrocortisone (S2), and capped with an olsalazine derivative, are prepared and fully characterized. Suspensions of S1 and S2 in water at an acidic and a neutral pH show negligible dye/drug release, yet a notable delivery took place when the reducing agent sodium dithionite is added because of hydrolysis of an azo bond in the capping ensemble. Additionally, olsalazine fragmentation induced 5-aminosalicylic acid (5-ASA) release. In vitro digestion models show that S1 and S2 solids are suitable systems to specifically release a pharmaceutical agent in the colon. In vivo pharmacokinetic studies in rats show a preferential rhodamine B release from S1 in the colon. Moreover, a model of ulcerative colitis is induced in rats by oral administration of 2,4,6-trinitrobenzenesulfonic acid (TNBS) solutions, which was also used to prove the efficacy of S2 for colitis treatment. The specific delivery of hydrocortisone and 5-ASA from S2 material to the colon tissue in injured rats markedly lowers the colon/body weight ratio and the clinical activity score. Histological studies showed a remarkable reduction in inflammation, as well as an intensive regeneration of the affected tissues.
Assuntos
Colite/tratamento farmacológico , Sistemas de Liberação de Medicamentos/métodos , Doenças Inflamatórias Intestinais/tratamento farmacológico , Dióxido de Silício/química , Animais , Hidrocortisona/química , Masculino , Mesalamina/química , Mesalamina/uso terapêutico , Ratos , Ratos Wistar , Rodaminas/química , Rodaminas/uso terapêuticoRESUMO
Four types of calcined MCM-41 silica nanoparticles, loaded with dyes and capped with different gating ensembles are prepared and characterized. N1 and N2 nanoparticles are loaded with rhodamine 6G and capped with bulky poly(ethylene glycol) derivatives bearing ester groups (1 and 2). N3-N4 nanoparticles are loaded with sulforhodamine B and capped with self-immolative derivatives bearing ester moieties. In the absence of esterase enzyme negligible cargo release from N1, N3 and N4 nanoparticles is observed whereas a remarkable release for N2 is obtained most likely due to the formation of an irregular coating on the outer surface of the nanoparticles. In contrast, a marked delivery is found in N1, N3, and N4 in the presence of esterase enzyme. The delivery rate is related to the hydrophilic/hydrophobic character of the coating shell. The use of hydrophilic poly(ethylene glycol) derivatives as gating ensembles on N1 and N2 enables an easy access of esterase to the ester moieties with subsequent fast cargo release. On the other hand, the presence of a hydrophobic monolayer on N3 and N4 partially hinders esterase enzyme access to the ester groups and the rate of cargo release was decreased.
RESUMO
A new environmentally-friendly, simple, selective and sensitive probe for detecting formaldehyde, based on naturally-occurring compounds, through either colorimetric or fluorescence changes, is described. The probe is able to detect formaldehyde in both solution and the gas phase with limits of detection of 0.24 mM and 0.7 ppm, respectively. The probe has been tested to study formaldehyde emission in contaminated real atmospheres. The supported probe is easy to use and to dispose, and is safe and suitable as an individual chemodosimeter.
Assuntos
Formaldeído/análise , Soluções/análise , Colorimetria , Limite de Detecção , Espectrometria de FluorescênciaRESUMO
Magnetic micro-sized mesoporous silica particles were used for the preparation of a gated material able to release an entrapped cargo in the presence of an azo-reducing agent and, to some extent, at acidic pH. The magnetic mesoporous microparticles were loaded with safranin O and the external surface was functionalized with an azo derivative 1 (bearing a carbamate linkage) yielding solid S1. Aqueous suspensions of S1 at pH 7.4 showed negligible safranin O release due to the presence of the bulky azo derivative attached onto the external surface of the inorganic scaffold. However, in the presence of sodium dithionite (azoreductive agent), a remarkable safranin O delivery was observed. At acidic pH, a certain safranin O release from S1 was also found. The pH-triggered safranin O delivery was ascribed to the acid-induced hydrolysis of the carbamate moiety that linked the bulky azo derivatives onto the mesoporous inorganic magnetic support. The controlled release behavior of S1 was also tested using a model that simulated the gastro intestinal tract.
Assuntos
Compostos Azo/química , Nanopartículas/química , Dióxido de Silício/química , Cloretos , Colo/metabolismo , Ditionita/química , Portadores de Fármacos , Liberação Controlada de Fármacos , Compostos Férricos , Compostos Ferrosos , Humanos , Concentração de Íons de Hidrogênio , Hidrólise , Magnetismo , Microesferas , Oxirredução , Fenazinas/administração & dosagem , Porosidade , Propriedades de SuperfícieRESUMO
A new colorimetric and fluorogenic probe, based on a 3-formyl boron dipyrromethene (BODIPY) phenylhydrazone, for the sensitive and selective detection NO2 (g) has been prepared. The probe in solution experiences a remarkable hypsochromic shift of its absorption and fluorescence emission bands in the presence gaseous NO2 (g), leading to limits of detection of few ppb. The probe also works in the solid phase, adsorbed on filter paper strips, or chemically immobilized on the surface of silica nanoparticles, with limits of detection to the naked eye of about 0.5â ppm.
RESUMO
Test strips that in combination with a portable fluorescence reader or digital camera can rapidly and selectively detect chemical warfare agents (CWAs) such as Tabun (GA), Sarin (GB), and Soman (GD) and their simulants in the gas phase have been developed. The strips contain spots of a hybrid indicator material consisting of a fluorescent BODIPY indicator covalently anchored into the channels of mesoporous SBA silica microparticles. The fluorescence quenching response allows the sensitive detection of CWAs in the µg m(-3) range in a few seconds.
Assuntos
Compostos de Boro/química , Substâncias para a Guerra Química/química , Agentes Neurotóxicos/química , Organofosfatos/química , Tempo de Protrombina/métodos , Sarina/química , Dióxido de Silício/química , Soman/química , Substâncias para a Guerra Química/análise , Agentes Neurotóxicos/análise , Organofosfatos/análise , Sarina/análise , Soman/análiseRESUMO
A new hybrid material based on sulforhodamineâ B dye-loaded silica mesoporous nanoparticles capped with a self-immolative gate has been synthesized and characterized. The gated material's controlled release behavior is monitored under different pH conditions. Under acidic and neutral conditions, a low level of dye release is detected. However, at slightly basic pH, significant dye release occurs owing to deprotonation of the phenol moiety in the capping molecule, which results in its disassembly.
RESUMO
A new chromo-fluorogenic probe, consisting of a biphenyl derivative containing both a silylbenzyl ether and a N,N-dimethylamino group, for NO2 detection in the gas phase has been developed. A clear colour change from colourless to yellow together with an emission quenching was observed when the probe reacted with NO2 . A limit of detection to the naked eye of about 0.1â ppm was determined and the system was successfully applied to the detection of NO2 in realistic atmospheric conditions.
Assuntos
Compostos Cromogênicos/química , Corantes Fluorescentes/química , Óxido Nítrico/química , Ar , Estrutura MolecularRESUMO
A BODIPY-containing Cu(II) -bipyridine complex for the simple selective fluorogenic detection of NO in air and in live cells is reported. The detection mechanism is based on NO-promoted Cu(II) to Cu(I) reduction, followed by demetallation of the complex, which results in the clearly enhanced emission of the boron dipyrromethene (BODIPY) unit.
RESUMO
The crystal structure of two neutral triarylmethane dyes with a p-quinone methide core was determined by X-ray diffraction analysis. The spectroscopic characteristics of both compounds in 23 solvents with different polarities or hydrogen-bonding donor (HBD) abilities has been studied as a function of three solvatochromic parameters (ET(30), π* and α). Both compounds 1 and 2 showed a pronounced bathochromic shift of the main absorption band on increasing solvent polarity and HBD ability. The correlation is better for compound 2 than for compound 1. The stronger effect and better correlation was observed for compound 2 with the increment of the solvent HBD ability (α parameter).
Assuntos
Corantes/química , Indolquinonas/química , Metano/análogos & derivados , Metano/química , Cristalografia por Raios X , Ligação de Hidrogênio , Metano/síntese química , Modelos Químicos , Estrutura Molecular , Difração de Raios XRESUMO
Two chromo-fluorogenic probes, each based on the boron dipyrromethene core, have been developed for the detection of nerve-agent mimics. These chemosensors display both a color change and a significant enhancement of fluorescence in the presence of diethylcyanophosphonate (DCNP) and diisopropylfluorophosphate (DFP). No interference from other organophosphorus compounds or acids has been observed. Two portable chemosensor kits have been developed and tested to demonstrate its practical application in real-time monitoring.
Assuntos
Boro/química , Corantes/química , Corantes Fluorescentes , Estrutura Molecular , FosforilaçãoRESUMO
A simple method based in multivariate analysis of (1)H NMR spectra profiles of urine samples can be used to detect patients with prostate cancer.
Assuntos
Espectroscopia de Ressonância Magnética/métodos , Neoplasias da Próstata/urina , Urinálise/métodos , Humanos , Espectroscopia de Ressonância Magnética/economia , Masculino , Análise Multivariada , Próstata/patologia , Neoplasias da Próstata/diagnóstico , Urinálise/economiaRESUMO
A novel colorimetric probe (P4) for the selective differential detection of DFP (a Sarin and Soman mimic) and DCNP (a Tabun mimic) was prepared. Probe P4 contains three reactive sites; i.e. (i) a nucleophilic phenol group able to undergo phosphorylation with nerve gases, (ii) a carbonyl group as a reactive site for cyanide; and (iii) a triisopropylsilyl (TIPS) protecting group that is known to react with fluoride. The reaction of P4 with DCNP in acetonitrile resulted in both the phosphorylation of the phenoxy group and the release of cyanide, which was able to react with the carbonyl group of P4 to produce a colour modulation from pink to orange. In contrast, phosphorylation of P4 with DFP in acetonitrile released fluoride that hydrolysed the TIPS group in P4 to yield a colour change from pink to blue. Probe P4 was able to discriminate between DFP and DCNP with remarkable sensitivity; limits of detection of 0.36 and 0.40 ppm for DCNP and DFP, respectively, were calculated. Besides, no interference from other organophosphorous derivatives or with presence of acid was observed. The sensing behaviour of P4 was also retained when incorporated into silica gel plates or onto polyethylene oxide membranes, which allowed the development of simple test strips for the colorimetric detection of DCNP and DFP in the vapour phase. P4 is the first probe capable of colorimetrically differentiating between a Tabun mimic (DCNP) and a Sarin and Soman mimic (DFP).
Assuntos
Compostos de Boro/química , Substâncias para a Guerra Química/análise , Sondas Moleculares/química , Organofosfatos/análise , Sarina/análise , Soman/análise , Acetonitrilas , Compostos de Boro/síntese química , Cor , Colorimetria , Humanos , Limite de Detecção , Membranas Artificiais , Mimetismo Molecular , Sondas Moleculares/síntese química , Fosforilação , Fitas Reagentes , Sarina/análogos & derivados , Sílica Gel , Solventes , Soman/análogos & derivados , Especificidade por SubstratoRESUMO
AIM: To determine the usefulness of neutrophil/lymphocyte (N/L) and platelet/lymphocyte (P/L) ratios as well as quantitative [18F]FDG PET/CT parameters as prognostic factors for overall survival (OS), cancer-specific survival (CSS) and progression-free survival (PFS) in patients with head and neck squamous cell carcinoma (HyN). MATERIAL AND METHODS: Sixty-six patients (56 men) diagnosed with HyN carcinoma were retrospectively assessed over an 8-year interval. Maximum SUV (SUVmax), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) parameters were determined from the PET/CT study at diagnosis. After treatment with chemoradiotherapy, patient survival was assessed. The Cox regression model and the Kaplan-Meier method were used to analyse prognostic factors and survival curves. RESULTS: Median follow-up was 50.4 months, with 39 recurrences-progressions and 39 deaths. In the univariate analysis, metabolic parameters, except SUVmax, were predictive factors for all three survivals and the two blood parameters were predictive for OS and EFS. TLG was the only predictive factor in the multivariate analysis. The three survival curves were significantly different for the metabolic parameters and the OS curve for the N/L ratio. Correlations were seen between N/L ratio, MTV and TLG. No correlations were demonstrated between P/L ratio and metabolic parameters. CONCLUSION: The use of haematological and metabolic markers would allow to identify patients with a high risk of recurrences and por survival and to individualise treatment by applying more aggressive therapies.
Assuntos
Neoplasias de Cabeça e Pescoço , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Masculino , Humanos , Prognóstico , Fluordesoxiglucose F18/metabolismo , Estudos Retrospectivos , Compostos Radiofarmacêuticos , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/terapiaRESUMO
The preparation of a new capped silica mesoporous material, Rh-Azo-S, for on-command delivery applications in the presence of target enzymes is described. The material consists of nanometric mesoporous MCM-41-like supports loaded with Rhodamine B and capped with an azopyridine derivative. The material was designed to show "zero delivery" and to display a cargo release in the presence of reductases and esterases, which are usually present in the colon, mainly due to intestinal microflora. The opening and cargo release of Rh-Azo-S in vitro studies were assessed and seen to occur in the presence of these enzymes, whereas no delivery was noted in the presence of pepsine. Moreover, Rh-Azo-S nanoparticles were used to study controlled Rhodamineâ B dye delivery in intracellular media. HeLa cells were employed for testing the "non"-toxicity of nanoparticles. Moreover, delivery of the dye in these cells, through internalization and enzyme-mediated gate opening, was confirmed by confocal microscopy. Furthermore, the nanoparticles capped with the Azo group and loaded with a cytotoxic camptothecin (CPT) were also prepared (solid CPT-Azo-S) and used as delivery nanodevices in HeLa cells. When this solid was employed, the cell viability decreased significantly due to internalization of the nanoparticles and delivery of the cytotoxic agent.
Assuntos
Compostos Azo/química , Oxirredutases/metabolismo , Piridinas/química , Compostos de Piridínio/química , Dióxido de Silício/química , Compostos Azo/síntese química , Compostos Azo/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Células HeLa , Humanos , Células MCF-7 , Nanopartículas/química , Oxirredutases/química , Porosidade , Compostos de Piridínio/síntese química , Compostos de Piridínio/toxicidade , Rodaminas/químicaRESUMO
This critical review is focused on examples reported from 1947 to 2010 related to the design of chromo-fluorogenic chemosensors and reagents for explosives (141 references).
Assuntos
Técnicas de Química Analítica/instrumentação , Substâncias Explosivas/análise , Fenômenos Ópticos , Colorimetria , Substâncias Explosivas/química , Indicadores e Reagentes/química , Espectrometria de FluorescênciaRESUMO
A new selective fluorogenic chemosensor for Hg2+, which combines a calixarene derivative with a BODIPY core as a fluorescent reporter, is described. The remarkable change in its fluorogenic properties in DMSO and CHCl3 has been analyzed. A study of its spectral properties on dilution, along with molecular modeling studies, allowed us to explain that this behavior involves the formation of a J-dimer, as well as how the sensing mechanism of Hg2+ proceeds.