RESUMEN
Over the last decades, the interface between two immiscible electrolyte solutions (ITIES) attracted considerable attention of the scientific community due to their vast applications, such as extraction, catalysis, partition studies and sensing. The aim of this Review is to highlight the potential of electrochemistry at the ITIES for analytical purposes, focusing on ITIES-based sensors for detection and quantification of chemically and biologically relevant (bio)molecules. We start by addressing the evolution of ITIES in terms of number of publications over the years along with an overview of their main applications (Chapter 1). Then, we provide a general historical perspective about pioneer voltammetric studies at water/oil systems (Chapter 2). After that, we discuss the most impacting improvements on ITIES sensing systems from both perspectives, set-up design (interface stabilization and miniaturization, selection of the organic solvent, etc.) and optimization of experimental conditions to improve selectivity and sensitivity (Chapter 3). In Chapter 4, we discuss the analytical applications of ITIES for electrochemical sensing of several types of analytes, including drugs, pesticides, proteins, among others. Finally, we highlight the present achievements of ITIES as analytical tool and provide future challenges and perspectives for this technology (Chapter 5).
Asunto(s)
Técnicas Electroquímicas , Electrólitos , Técnicas Electroquímicas/métodos , Electrólitos/química , Humanos , SolucionesRESUMEN
Soil contamination with metals is a major threat for the environment and public health since most metals are toxic to humans and to non-human biota, even at low concentrations. Thus, new sustainable remediation approaches are currently needed to immobilize metals in soils to decrease their mobility and bioavailability. In this work, we explore the application of discarded substrates from hydroponic cultivation, namely coconut shell and a mixture of coconut shell and pine bark, for immobilization of metals (Cd, Cr, Ni, Cu, Pb, Hg, Sb and As) in a naturally contaminated soil from a mining region in Portugal. The immobilization capacity of substrates (added to the soil at 5% mass ratio) was assessed both individually and also combined with other traditional agriculture soil additives (limestone and gypsum, at 2% mass ratio) and nanoparticles of zero-valent iron (nZVI) at 1-3% mass ratio. The overall results obtained after a 30-d incubation showed that the discarded substrates are a viable, economic, and environmental-friendly solution for metal remediation in soils, with the capacity of immobilization ranging from 20 to 91% for the metals and metalloids studied. Furthermore, they showed the capacity to reduce the soil toxicity (EC50 â¼ 6000 mg/L) to non-toxic levels (EC50 > 10000 mg/L) to the bacteria Aliivrio fischeri.
RESUMEN
Over the past decade, molecular imprinting (MI) technology has made tremendous progress, and the advancements in nanotechnology have been the major driving force behind the improvement of MI technology. The preparation of nanoscale imprinted materials, i.e., molecularly imprinted polymer nanoparticles (MIP NPs, also commonly called nanoMIPs), opened new horizons in terms of practical applications, including in the field of sensors. Currently, hydrogels are very promising for applications in bioanalytical assays and sensors due to their high biocompatibility and possibility to tune chemical composition, size (microgels, nanogels, etc.), and format (nanostructures, MIP film, fibers, etc.) to prepare optimized analyte-responsive imprinted materials. This review aims to highlight the recent progress on the use of hydrogel MIP NPs for biosensing purposes over the past decade, mainly focusing on their incorporation on sensing devices for detection of a fundamental class of biomolecules, the peptides and proteins. The review begins by directing its focus on the ability of MIPs to replace biological antibodies in (bio)analytical assays and highlight their great potential to face the current demands of chemical sensing in several fields, such as disease diagnosis, food safety, environmental monitoring, among others. After that, we address the general advantages of nanosized MIPs over macro/micro-MIP materials, such as higher affinity toward target analytes and improved binding kinetics. Then, we provide a general overview on hydrogel properties and their great advantages for applications in the field of Sensors, followed by a brief description on current popular routes for synthesis of imprinted hydrogel nanospheres targeting large biomolecules, namely precipitation polymerization and solid-phase synthesis, along with fruitful combination with epitope imprinting as reliable approaches for developing optimized protein-imprinted materials. In the second part of the review, we have provided the state of the art on the application of MIP nanogels for screening macromolecules with sensors having different transduction modes (optical, electrochemical, thermal, etc.) and design formats for single use, reusable, continuous monitoring, and even multiple analyte detection in specialized laboratories or in situ using mobile technology. Finally, we explore aspects about the development of this technology and its applications and discuss areas of future growth.
Asunto(s)
Nanosferas , Nanoestructuras , Polímeros/química , Nanogeles , Hidrogeles/químicaRESUMEN
A fast method based on reversed-phase ultra-high-performance liquid chromatography using evaporative light scattering detection (RP-UHPLC-ELSD) was developed for monitoring the intermediates and end products of biodiesel production. Gradient elution of water, acetonitrile, and a mixture of acetonitrile:2-propanol:n-hexane was used. With a minimal and easy sample preparation, fatty acid methyl esters (FAME), fatty acid ethyl esters (FAEE), free fatty acids (FFA), monoacylglycerols (MAG), diacylglycerols (DAG), and triacylglycerols (TAG) were successfully separated. The developed method was used to monitor an ethylic enzymatic transesterification of soybean oil and to characterize the ester content of methyl and ethyl biodiesel. The ester content obtained was compared with the reference method by gas chromatography and flame ionization detector (GC-FID), with similar results for both methyl and ethyl biodiesel. The presented method is a simple and fast alternative, a 17 min run, to monitor the transesterification process, simultaneously quantifying all the analytes produced in the reaction: biodiesel and its intermediates. Limits of detection (LOD, between 29 and 307 ng) and quantification (LOQ, between 48 and 614 ng), linearity (R2>0.99), precision (between 0.30 and 6.58%), and accuracy (between 81.6 and 119.9%) were determined for the twenty-one compounds.
Asunto(s)
Biocombustibles , Cromatografía de Fase Inversa , Cromatografía Líquida de Alta Presión , Ésteres , Ácidos GrasosRESUMEN
In this work, we describe an innovative methodology based on combined surface plasmon resonance (SPR) and electrochemical responses (eSPR) in the same immunoassay for screening CA 15-3 cancer biomarker with high sensitivity (and selectivity), in a very simple, label-free, accurate, and fully automated manner. Detection was achieved by performing two simple steps. In the first step, direct SPR was used to monitor CA 15-3 interaction with surface immobilized antibody. Two linear response ranges were obtained and the detection limit achieved is poor (LOD of 21 U mL-1). However, in the second detection step, electrochemical measurements at the SPR gold surface were performed to measure the decrease of redox probe peak current upon antigen-antibody interaction, providing a suitable amplification strategy to lower detection levels of CA 15-3 (LOD of 0.0998 U mL-1), without the need of additional complex and/or expensive amplification steps to enhance the sensitivity. Moreover, selectivity studies were performed against other common cancer biomarkers and the results showed that the eSPR immunosensor is selective for the CA 15-3 protein. Finally, the clinical applicability of the developed eSPR biosensing methodology was successfully applied to detect CA 15-3 in human serum samples at clinically relevant levels due to the high sensitivity of electrochemical readout. The same concept may be further extended to other proteins of interest.
Asunto(s)
Técnicas Biosensibles , Resonancia por Plasmón de Superficie , Electroquímica , Oro , Humanos , Inmunoensayo , Límite de DetecciónRESUMEN
INTRODUCTION: The characteristics of D. fragilis infection are described, with special focus on the clinical and epidemiological aspects. MATERIALS AND METHODS: A retrospective and descriptive study was performed, including all the patients with Dientamoeba fragilis infection who attended a specialized unit between January 2012 and December 2017. PCR was used to diagnose D. fragilis. Patients were treated with metronidazole or paromomycin and reviewed at four and eight weeks post-treatment. Cure was defined as the negativization of all parasitological tests, in absence of symptoms. RESULTS: 163 patients were diagnosed. The most frequent symptoms were abdominal pain (36.2%), chronic diarrhoea (12.3%), anal itching (10.4%), abdominal discomfort (9.2%), skin disease (8%), acute diarrhoea (4.3%) and vomiting (4.3%). Fifty patients were asymptomatic. Forty-two patients had eosinophilia in blood. Thirty-eight cases (23.3%) had a coinfection by Enterobius vermicularis. One hundred and seven patients received treatment, sixty-one of them with metronidazole and the rest with paromomycin. Ninety-nine patients (91%) were cured. The rate of cure was 100% in the paromomycin group versus 86.8% in the metronidazole group (p = 0.005; OR: 1.173 [1.057-1.302]). The absence of cure was associated with E. vermicularis coinfection (p = 0.014; OR: 6.167 [1.432-26.563] and with longer duration of the symptoms (175 [± 159SD]) versus 84 [± 88SD] days, p = 0.014) but multivariable analysis did not confirm these associations. CONCLUSION: Dientamoeba fragilis is an important and underestimated cause of gastrointestinal disease in both the autochthonous and immigrant or traveller population. More studies are needed to clarify its optimal treatment and the role played by E. vermicularis in its transmission and maintenance
INTRODUCCIÓN: Se describen las características clínicas y epidemiológicas de la infección por Dientamoeba fragilis. MATERIAL Y MÉTODOS: Se realizó un estudio retrospectivo y descriptivo de los pacientes diagnosticados de infección por D. fragilis en una unidad especializada entre 2012-2017. El diagnóstico de D. fragilis se realizó mediante PCR. Los pacientes fueron tratados con metronidazol o paromomicina y revisados a las 4 y 8 semanas tras tratamiento. Se consideró a los pacientes curados tras negativización microbiológica en ausencia de síntomas. RESULTADOS: Se analizaron 163 pacientes. Los síntomas más frecuentes fueron: dolor abdominal (36,2%), diarrea crónica (12,3%), prurito anal (10,4%), malestar abdominal (9,2%), síntomas cutáneos (8%), diarrea aguda y vómitos (4,3%, respectivamente). Cincuenta pacientes estaban asintomáticos. Cuarenta y dos pacientes presentaron eosinofilia. En 38 pacientes se observó coinfección por Enterobius vermicularis. Ciento siete pacientes recibieron tratamiento, 61 con metronidazol y el resto con paromomicina, con una curación del 91%. La tasa de curación fue del 100% en los pacientes tratados con paromomicina y del 86,8% en el grupo del metronidazol (p = 0,005; OR: 1,173 [1,057-1,302]). La no curación se asoció a la coinfección por E. vermicularis (p = 0,014; OR: 6,167 [1,432-26,563]) y con la mayor duración de los síntomas (175 [± 159 DE] versus 84 [± 88 DE] días; p = 0,014), pero el análisis multivariable no confirmó dichas asociaciones. CONCLUSIÓN: D. fragilis es causa importante y subestimada de enfermedad gastrointestinal tanto en poblaciones autóctonas como inmigrantes o viajeros. Se necesitan más estudios para aclarar su tratamiento óptimo y el papel desempeñado por E. vermicularis en su tratamiento
Asunto(s)
Humanos , Masculino , Femenino , Niño , Adolescente , Adulto , Dientamebiasis/epidemiología , Enterobius/microbiología , Enfermedades Parasitarias/microbiología , Estudios Retrospectivos , Dientamebiasis/tratamiento farmacológico , Metronidazol/uso terapéutico , Coinfección/microbiologíaRESUMEN
INTRODUCTION: The characteristics of D. fragilis infection are described, with special focus on the clinical and epidemiological aspects. MATERIALS AND METHODS: A retrospective and descriptive study was performed, including all the patients with Dientamoeba fragilis infection who attended a specialized unit between January 2012 and December 2017. PCR was used to diagnose D. fragilis. Patients were treated with metronidazole or paromomycin and reviewed at four and eight weeks post-treatment. Cure was defined as the negativization of all parasitological tests, in absence of symptoms. RESULTS: 163 patients were diagnosed. The most frequent symptoms were abdominal pain (36.2%), chronic diarrhoea (12.3%), anal itching (10.4%), abdominal discomfort (9.2%), skin disease (8%), acute diarrhoea (4.3%) and vomiting (4.3%). Fifty patients were asymptomatic. Forty-two patients had eosinophilia in blood. Thirty-eight cases (23.3%) had a coinfection by Enterobius vermicularis. One hundred and seven patients received treatment, sixty-one of them with metronidazole and the rest with paromomycin. Ninety-nine patients (91%) were cured. The rate of cure was 100% in the paromomycin group versus 86.8% in the metronidazole group (p=0.005; OR: 1.173 [1.057-1.302]). The absence of cure was associated with E. vermicularis coinfection (p=0.014; OR: 6.167 [1.432-26.563] and with longer duration of the symptoms (175 [±159SD]) versus 84 [±88SD] days, p=0.014) but multivariable analysis did not confirm these associations. CONCLUSION: Dientamoeba fragilis is an important and underestimated cause of gastrointestinal disease in both the autochthonous and immigrant or traveller population. More studies are needed to clarify its optimal treatment and the role played by E. vermicularis in its transmission and maintenance.
Asunto(s)
Dientamebiasis , Adulto , Antiprotozoarios/uso terapéutico , Dientamebiasis/diagnóstico , Dientamebiasis/tratamiento farmacológico , Dientamebiasis/epidemiología , Femenino , Humanos , Masculino , Metronidazol/uso terapéutico , Persona de Mediana Edad , Paromomicina/uso terapéutico , Estudios Retrospectivos , Adulto JovenRESUMEN
INTRODUCTION: The results of a study on the household contacts of patients with D. fragilis infection are presented. METHODS: A prospective, descriptive study was carried out on all Dientamoeba fragilis-infected patients treated at the Tropical Medicine Unit of Hospital Universitario Central de Asturias between 2012- 2017 and their household contacts. Three stool samples per patient and three stool samples from each of their household contacts were concentrated and analysed. Polymerase chain reaction (PCR) was used to detect the presence of D. fragilis in all stool samples. Co-infection with E. vermicularis was studied in both groups. Patients and contacts who failed to deliver one or more samples for diagnosis and patients without household contacts were excluded. RESULTS: 44 Patients infected with D. fragilis, as well as their 97 household contacts were enrolled. 50.5% of household contacts had a positive PCR for D. fragilis. 20 were also coinfected with E. vermicularis. The presence of infection was significantly more frequent in patients with children (34/15 versus 24/24; p= 0.064; OR: 2.267 [0.988-5.199]), E. vermicularis infection in the children being 20/29 versus 0/48 (p = 0.0001), and in another family member being 29/20 versus 15/33 (p = 0.008; OR: 3.190 [1.384-7.352]). CONCLUSIONS: The prevalence of D. fragilis infection in household contacts was high. It was associated with the presence of children in the family nucleus and coinfection with E. vermicularis irrespective of gender, age, rural area or contact with animals
INTRODUCCIÓN: Los informes de sensibilidad acumulada son una herramienta valiosa para guiar el tratamiento empírico de infecciones urinarias, sobre todo en el contexto actual de crecientes tasas de resistencia. Nuestro objetivo es analizar la sensibilidad antimicrobiana de bacterias aisladas de urocultivos de pacientes pediátricos durante un período de 5 años. MÉTODOS: Estudio retrospectivo de los urocultivos del período 2011-2015. La identificación y estudios de sensibilidad se realizaron con el sistema Vitek-2 (BioMérieux(R)) y se interpretaron según los criterios de EUCAST. Se analizaron los datos de sensibilidad antimicrobiana según sexo y tramos de edad (neonatos, 1 mes-5 años, 5-15 años) y se compararon con los datos de mayores de 15 años. RESULTADOS: En el período analizado se procesaron 17.164 urocultivos de 7.924 pacientes menores de 16 años. Los porcentajes de sensibilidad en estos pacientes fueron: ampicilina 36,3%; amoxicilina/clavulánico 75,3%; cefuroxima 83,2%; cotrimoxazol 68,9%; ciprofloxacino 85,3%; fosfomicina 85,5%; nitrofurantoína 84,4%, y cefalosporinas de tercera generación 89-91%. Aminoglucósidos (>92%) y carbapenemas (95%) mantienen las mayores tasas de sensibilidad. La prevalencia de aislamientos productores de BLEE fue significativamente menor en niños menores de 16 años (1,5% vs. 4,1%). En menores de 16 años, los aislamientos de Escherichia coli procedentes de mujeres fueron significativamente (p < 0,0001) más sensibles a ampicilina (41% vs. 30%) y amoxicilina-clavulánico (82% vs. 72%) que en varones. CONCLUSIONES: La elaboración de informes de sensibilidad acumulados desglosados por edad o sexo permite detectar importantes diferencias. En nuestra área, cefuroxima puede considerarse como primera opción de tratamiento empírico en pacientes pediátricos
Asunto(s)
Humanos , Masculino , Femenino , Preescolar , Niño , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Anciano , Bacteroides fragilis/genética , Infecciones por Bacteroides/diagnóstico , Infecciones por Bacteroides/epidemiología , Trazado de Contacto , Infecciones por Bacteroides/transmisión , Reacción en Cadena de la Polimerasa , Estudios Prospectivos , PrevalenciaRESUMEN
In this work, we report for the first time the accumulation activity by energized rat heart mitochondria and the ionic transfer process at a liquid-liquid interface of a novel mitochondria-targeted antioxidant, named as AntiOxCIN4, which is structurally based on a hydroxycinnamic acid. Lipophilicity studies conducted at the water/1,6-dichlorohexane (DCH) interface allowed the building up of an ionic partition diagram of AntiOxCIN4 in accordance with the electrochemical data obtained. The partition coefficients of both positively charged (-2.3) and zwitterionic (0.2) forms of the antioxidant were determined. This study contributed to gaining an insight about the ability of the synthesized antioxidants to cross biomembrane barriers by using an interface between two immiscible electrolyte solutions (ITIES) as a model system.
Asunto(s)
Antioxidantes/química , Antioxidantes/metabolismo , Ciclohexanos/química , Mitocondrias/metabolismo , Agua/química , Animales , Electroquímica , Concentración de Iones de Hidrógeno , Ratas , SolucionesRESUMEN
INTRODUCTION: The results of a study on the household contacts of patients with D. fragilis infection are presented. METHODS: A prospective, descriptive study was carried out on all Dientamoeba fragilis-infected patients treated at the Tropical Medicine Unit of Hospital Universitario Central de Asturias between 2012- 2017 and their household contacts. Three stool samples per patient and three stool samples from each of their household contacts were concentrated and analysed. Polymerase chain reaction (PCR) was used to detect the presence of D. fragilis in all stool samples. Co-infection with E. vermicularis was studied in both groups. Patients and contacts who failed to deliver one or more samples for diagnosis and patients without household contacts were excluded. RESULTS: 44 Patients infected with D. fragilis, as well as their 97 household contacts were enrolled. 50.5% of household contacts had a positive PCR for D. fragilis. 20 were also coinfected with E. vermicularis. The presence of infection was significantly more frequent in patients with children (34/15 versus 24/24; p= 0.064; OR: 2.267 [0.988-5.199]), E. vermicularis infection in the children being 20/29 versus 0/48 (p=0.0001), and in another family member being 29/20 versus 15/33 (p=0.008; OR: 3.190 [1.384-7.352]). CONCLUSIONS: The prevalence of D. fragilis infection in household contacts was high. It was associated with the presence of children in the family nucleus and coinfection with E. vermicularis irrespective of gender, age, rural area or contact with animals.
Asunto(s)
Dientamoeba/aislamiento & purificación , Dientamebiasis/epidemiología , Adolescente , Adulto , Anciano , Niño , Preescolar , Coinfección/epidemiología , Coinfección/parasitología , Trazado de Contacto , Dientamebiasis/parasitología , Dientamebiasis/transmisión , Disentería Amebiana/epidemiología , Entamoeba/aislamiento & purificación , Composición Familiar , Heces/parasitología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Estudios Prospectivos , España/epidemiología , Adulto JovenRESUMEN
Oxidative stress and mitochondrial dysfunction have been associated with metabolic and age-related diseases. Thus, the prevention of mitochondrial oxidative damage is nowadays a recognized pharmacological strategy to delay disease progression. Epidemiological studies suggested an association between the consumption of polyphenol-rich diet and the prevention of different pathologies, including diseases with a mitochondrial etiology. The development of mitochondrial-targeted antioxidants based on dietary antioxidants may decrease mitochondrial oxidative damage. Herein, we report the design and synthesis of two new mitochondriotropic antioxidants based on hydroxybenzoic acids (AntiOxBENs). The results obtained showed that the novel antioxidants are accumulated inside rat liver mitochondria driven by the organelle transmembrane electric potential and prevented lipid peroxidation, exhibiting low toxicity. Some of the observed effects on mitochondrial bioenergetics resulted from an increase of proton leakage through the mitochondrial inner membrane. The new derivatives present a higher lipophilicity than the parent compounds (protocatechuic and gallic acids) and similar antioxidant and iron chelating properties. AntiOxBENs are valid mitochondriotropic antioxidant prototypes, which can be optimized and used in a next future as drug candidates to prevent or slow mitochondrial oxidative stress associated to several pathologies.
Asunto(s)
Antioxidantes/farmacología , Hidroxibenzoatos/farmacología , Quelantes del Hierro/farmacología , Mitocondrias Hepáticas/efectos de los fármacos , Animales , Antioxidantes/administración & dosificación , Antioxidantes/síntesis química , Línea Celular , Respiración de la Célula , Suplementos Dietéticos , Células Hep G2 , Humanos , Hidroxibenzoatos/administración & dosificación , Hidroxibenzoatos/síntesis química , Quelantes del Hierro/administración & dosificación , Quelantes del Hierro/síntesis química , Masculino , Mitocondrias Hepáticas/metabolismo , Ratas , Ratas WistarRESUMEN
Targeting mitochondrial oxidative stress is an effective therapeutic strategy. In this context, a rational design of mitochondriotropic antioxidants (compounds 22-27) based on a dietary antioxidant (caffeic acid) was performed. Jointly named as AntiOxCINs, these molecules take advantage of the known ability of the triphenylphosphonium cation to target active molecules to mitochondria. The study was guided by structure-activity-toxicity-property relationships, and we demonstrate in this work that the novel AntiOxCINs act as mitochondriotropic antioxidants. In general, AntiOxCINs derivatives prevented lipid peroxidation and acted as inhibitors of the mitochondrial permeability transition pore. AntiOxCINs toxicity profile was found to be dependent on the structural modifications performed on the dietary antioxidant. On the basis of mitochondrial and cytotoxicity/antioxidant cellular data, compound 25 emerged as a potential candidate for the development of a drug candidate with therapeutic application in mitochondrial oxidative stress-related diseases. Compound 25 increased GSH intracellular levels and showed no toxicity on mitochondrial morphology and function.
Asunto(s)
Antioxidantes/farmacología , Ácidos Cafeicos/farmacología , Mitocondrias/metabolismo , Estrés Oxidativo/efectos de los fármacos , Animales , Antioxidantes/síntesis química , Antioxidantes/toxicidad , Ácidos Cafeicos/síntesis química , Ácidos Cafeicos/toxicidad , Ácido Glutámico/metabolismo , Glutatión/metabolismo , Células Hep G2 , Humanos , Hierro/química , Quelantes del Hierro/síntesis química , Quelantes del Hierro/farmacología , Quelantes del Hierro/toxicidad , Peroxidación de Lípido/efectos de los fármacos , Malatos/metabolismo , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/antagonistas & inhibidores , Poro de Transición de la Permeabilidad Mitocondrial , Ratas , Ácido Succínico/metabolismoRESUMEN
This work describes the state of the art of electrochemical devices for the detection of an important class of neurotransmitters: the catecholamines. This class of biogenic amines includes dopamine, noradrenaline (also called norepinephrine) and adrenaline (also called epinephrine). Researchers have focused on the role of catecholamine molecules within the human body because they are involved in many important biological functions and are commonly associated with several diseases, such as Alzheimer's and Parkinson. Furthermore, the release of catecholamines as a consequence of induced stimulus is an important indicator of reward-related behaviors, such as food, drink, sex and drug addiction. Thus, the development of simple, fast and sensitive electroanalytical methodologies for the determination of catecholamines is currently needed in clinical and biomedical fields, as they have the potential to serve as clinically relevant biomarkers for specific disease states or to monitor treatment efficacy. Currently, three main strategies have used by researchers to detect catecholamine molecules, namely: the use electrochemical materials in combination with, for example, HPLC or FIA, the incorporation of new materials/layers on the sensor surfaces (Tables 1-7) and in vivo detection, manly by using FSCV at CFMEs (Section 10). The developed methodologies were able not only to accurately detect catecholamines at relevant concentration levels, but to do so in the presence of co-existing interferences in samples detected (ascorbate, for example). This review examines the progress made in electrochemical sensors for the selective detection of catecholamines in the last 15 years, with special focus on highly innovative features introduced by nanotechnology. As the literature in rather extensive, we try to simplify this work by summarizing and grouping electrochemical sensors according to the manner their substrates were chemically modified. We also discuss the current and future of electrochemical sensors for catecholamines in terms of the analytical performance of the devices and emerging applications.
Asunto(s)
Técnicas Biosensibles , Catecolaminas/análisis , Neurotransmisores/análisis , Animales , Técnicas Electroquímicas , Humanos , NanotecnologíaRESUMEN
Paraoxonase 1 (PON1) is an enzyme that prevents the peroxidation of lipoprotein and cell membranes. Our hypothesis is that the effect of the PON1 T(-107)C polymorphism on serum PON1 activity in healthy adult women is dependent on their fatty acid intake profile. This study included women (n = 39) who completed a food frequency questionnaire. Fatty acid intake was estimated based on the interview and a nutrient reference table. Blood samples were collected for genotyping and to measure serum PON1 activity. Serum PON1 activity was different among genotypes and was higher for women of the CC genotype (P < .001). Women in the study were categorized in 2 groups according to the median nutrient intake. Overall, there was a difference (P < .05) in serum PON1 activity between the CC and TT genotypes in women ingesting either above or below the median total fat, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, omega 3 (n-3) and omega 6 (n-6; P < .05). However, genotype effects on serum PON1 activity were not observed in women ingesting below the median (15:1) ratio of n-6/n-3 (P > .05) but were observed in women ingesting above the ratio of n-6/n-3 (P < .05). This is partly because women of the CC genotype had decreased PON1 activity when ingesting a lower ratio of n-6/n-3 diet (P < .05), while women of the TT genotype had increased PON1 activity (P < .05). In conclusion, the overall presence of the C allele was associated with increased serum PON1 activity, although a diet with high saturated fatty acid or a low ratio of n-6/n-3 reduced PON1 activity in women with the CC genotype.
Asunto(s)
Arildialquilfosfatasa/genética , Dieta Alta en Grasa/efectos adversos , Ácidos Grasos Omega-3/administración & dosificación , Ácidos Grasos Omega-6/administración & dosificación , Polimorfismo de Nucleótido Simple , Regiones Promotoras Genéticas , Adolescente , Adulto , Arildialquilfosfatasa/sangre , Arildialquilfosfatasa/metabolismo , Brasil , Estudios Transversales , Enfermedades Carenciales/sangre , Enfermedades Carenciales/enzimología , Enfermedades Carenciales/etiología , Enfermedades Carenciales/genética , Ácidos Grasos Esenciales/deficiencia , Ácidos Grasos Omega-3/efectos adversos , Ácidos Grasos Omega-6/efectos adversos , Ácidos Grasos Omega-6/deficiencia , Femenino , Estudios de Asociación Genética , Hospitales Universitarios , Humanos , Peroxidación de Lípido , Persona de Mediana Edad , Encuestas Nutricionales , Adulto JovenRESUMEN
In this work, the ion transfer mechanism of the anticancer drug daunorubicin (DNR) at a liquid/liquid interface has been studied for the first time. This study was carried out using electrochemical techniques, namely cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The lipophilicity of DNR was investigated at the water/1,6-dichlorohexane (DCH) interface, and the results obtained were presented in the form of an ionic partition diagram. The partition coefficients of both neutral and ionic forms of the drug were determined. The analytical parameter for the detection of DNR was also investigated in this work. An electrochemical DNR sensor is proposed by means of simple ion transfer at the water/DCH interface, using DPV as the quantification technique. Experimental conditions for the analytical determination of DNR were established, and a detection limit of 0.80 µM was obtained.
Asunto(s)
Antibióticos Antineoplásicos/química , Daunorrubicina/química , Técnicas Electroquímicas/métodos , Aceites/química , Agua/química , Antibióticos Antineoplásicos/metabolismo , Daunorrubicina/metabolismo , Humanos , Aceites/metabolismo , Agua/metabolismoRESUMEN
In this work, ion transfer and facilitated ion transfer of ammonium ion by a lipophilic cyclodextrin is investigated at the water/1,6-dichlorohexane micro-interface, using electrochemical approaches (cyclic voltammetry, differential pulse voltammetry and square wave voltammetry). The association constant has been obtained for the complex between ammonium ion and the cyclodextrin. Experimental conditions for the analytical determination of ammonium ion were established and a detection limit of 0.12 µM was obtained. The amperometric sensor gave a current response proportional to the ammonium ion concentration in the range from 4.2 to 66 µM.
Asunto(s)
Ciclohexanos/química , Potenciometría/métodos , Compuestos de Amonio Cuaternario/análisis , Agua/química , Cationes , Ciclodextrinas/química , Límite de DetecciónRESUMEN
Thin films composed of oleylamine (OLA) and double-stranded deoxyribonucleic acid (dsDNA from Salmon testes) have been successfully constructed on polycrystalline Au surfaces using the electrostatic adsorption and self-assembly (SA) technique. The formation of the Au/OLA/dsDNA films was followed step-by-step by Quartz Crystal Microbalance with energy dissipation (QCM-D), Atomic Force Microscopy (AFM), and electrochemical techniques such as Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The use of these techniques allowed the characterization and the follow up of the successful construction of the OLA/dsDNA composite film. The main advantages of the proposed methodology are the simplicity of the modification procedure, the stability of the dsDNA self-assembled film, and the potential employment of the dsDNA modified gold electrodes to study the interactions of DNA with target molecules.
Asunto(s)
Aminas/química , ADN/química , Oro/química , Adsorción , Animales , Electrodos , Métodos , Salmón , Propiedades de SuperficieRESUMEN
Interfaces between two immiscible electrolyte solutions are recognized as a simplified model for biological systems and they can be of great relevance to the characterization of biomolecules and their role in biological systems. In this work, ion transfer and facilitated ion transfer of protonated catecholamines (dopamine and noradrenaline) by dibenzo-18-crown-6 are investigated at the water/1,6-dichlorohexane interface. The formation constant of the complex between both dopamine and noradrenaline with dibenzo-18-crown-6 was evaluated and the experimental conditions for the analytical determination of those catecholamines are established. These results can improve the understanding of the pharmacodynamics of the catecholamines, and contribute to the study of their interaction with biological membranes. Furthermore it can be used to develop an alternative method for the determination of neural signal transmission catecholamines.
Asunto(s)
Ciclohexanos/química , Dopamina/análisis , Norepinefrina/análisis , Dopamina/química , Electroquímica , Estructura Molecular , Norepinefrina/química , Agua/químicaRESUMEN
Foi realizado um estudo imuno-histoquímico para verificar a expressäo de enolase neurônio-específica (NSE), alfa 1-antitripsina (AAT) e alfa 1-antiquimotripsina (AAQT) em tumores malignos de células germinativas do ovário. As reaçöes imuno-histoquímicas foram realizadas em tecidos previamente fixados em formol e embebidos em parafina de sete disgerminomas, três tumores do seio endodérmico, três teratomas imaturos e um oriocarcinoma. Todos os tumores, exceto o coriocarcinoma, expressaram NSE. As reaçös com anticorpos anti-AAT e AAQT foram positivas em todos os tipos histológicos dos tumores. Estes dados sugerem que NSE, AAT ou AAQT podem ser mais um marcador para os tumores de células germinativas do ovário.