Electrochemical biosensor for quantitative determination of fentanyl based on immobilized cytochrome c on multi-walled carbon nanotubes modified screen-printed carbon electrodes.

Fentanyl is a powerful synthetic opioid used to treat severe pain. New administration routes toward its illegal consumption for recreational purposes pose a growing threat to public health, either due to misuse or abuse of this substance. As a result, the rapid qualitative and quantitative determination of fentanyl in biofluids is of great interest. A novel enzymatic biosensor based on adsorptive-stripping cyclic voltammetry is proposed as a cost-effective, reliable, and efficient device for fentanyl determination in urine samples. Disposable screen-printed carbon electrodes modified with multi-walled carbon nanotubes and cytochrome c were used to develop the testing platform. The electrochemical behavior of fentanyl exhibited a well-defined anodic wave around 0.66 V vs. pseudo reference electrode. The experimental conditions were optimized to obtain the best analytical response, and linear regression analysis of increasing concentration standards was applied to estimate the performance parameters. The results suggest a simple method with a wide linearity range, high sensitivity, low limits of detection (0.086 µg/mL) and quantification, and satisfactory precision (2.9% RSD). The feasibility and applicability of the voltammetric approach were assessed by fentanyl-spiked urine samples by standard additions calibration curves in two levels of enrichment with an accuracy of 92% and 100%.

Caraterísticas de graduados de los programas de postgrado, por áreas de conocimiento. Universidad de panamá / Characteristics of graduates of postgraduate programs, by areas of knowledge. University of Panama / Características dos egressos de programas de pós graduação, por áreas de conhecimento. Universidade do Panamá

Estudio descriptivo, retrospectivo, longitudinal; que realiza la descripción de algunas características de los egresados de los programas de postgrado en el periodo 1990 a 2014 y su clasificación según las áreas de conocimiento oficiales de la Universidad de Panamá. La población fueron todos los egresados de los programas de postgrado, ofrecidos por las unidades académicas y registrados en los archivos oficiales de la Universidad de Panamá, suministrados por la Dirección de Planificación y Evaluación Universitaria. Las áreas de conocimiento aprobadas en la Universidad de Panamá son cuatro: Ciencias Económicas y Administrativas; Ciencias de la Salud; Ciencias Sociales, Humanísticas y Culturales; Ciencias Naturales, Exactas y Tecnología. Con la inclusión de todas las unidades académicas según su campo disciplinar en investigación, estudios de postgrado y el grado. La Vicerrectoría de Investigación y Postgrado, en 25 años con el desarrollo de los programas de postgrado, ha logrado un total de 41,969 graduados, Sobresaliendo con 91,6% los graduados de programas desarrollados en Ciudad Universitaria, de los cuales 43,7% en el periodo 1990 a 2000, 14,9% en el periodo del 2001 al 2006 y 33% del 2007 al 2014, la mayoría del sexo femenino. Que, al clasificarlos por áreas de conocimientos establecidas en la Universidad de Panamá, observamos un mayor porcentaje (74,4%) del área de las Ciencias Sociales, Humanísticas y Culturales. Seguido con 11,5% del área de Ciencias Económicas y Administrativas, 8,7% del área de Ciencias de la Salud y 5,4% del área de Ciencias Naturales, Exactas y Tecnológicas. Los programas de postgrado con mayor población de estudiantes graduados se concentran en las áreas de Ciencias Económicas y Administrativas, y el área de Ciencias Sociales, Humanísticas y Culturales. Oferta permanente de varios grupos en todas las sedes de la Universidad de Panamá.

ABSTRACT Descriptive, retrospective, longitudinal study; which performs the description of some characteristics of the graduates of the postgraduate programs in the period from 1990 to 2014 and their classification according to the official knowledge areas of the University of Panama. The population was all graduates of the postgraduate programs, offered by the academic units and registered in the official archives of the University of Panama, supplied by the Department of Planning and University Evaluation. Results and Discussion: The areas of knowledge approved at the University of Panama are four: Economic and Administrative Sciences; Health Sciences; Social, Humanistic and Cultural Sciences; Natural, Exact Sciences and Technology. With the inclusion of all academic units according to their disciplinary field in research, postgraduate studies and degree. The Vice-rectorate for Research and Postgraduate Studies, in 25 years with the development of postgraduate programs, has achieved a total of 41,969 graduates, Outstanding with 91,6% graduates of programs developed in University City, of which 43,7% in the period 1990 to 2000, 14,9% in the period from 2001 to 2006 and 33% from 2007 to 2014, most of them female. When classified by areas of knowledge established in the University of Panama, we observe a greater percentage (74,4%) of the area of Social, Humanistic and Cultural Sciences. Followed by 11,5% of the area of Economic and Administrative Sciences, 8,7% of the area of Health Sciences and 5,4% of the area of Natural, Exact Sciences and Technology.

RESUMO Estudo descritivo, retrospectivo, longitudinal; o que faz a descrição de algumas características dos egressos dos programas de pós-graduação no período de 1990 a 2014 e sua classificação de acordo com as áreas oficiais de conhecimento da Universidade do Panamá. A população era toda egressa dos programas de pós-graduação, oferecidos pelas unidades acadêmicas e registrados nos arquivos oficiais da Universidade do Panamá, fornecidos pela Diretoria de Planejamento e Avaliação Universitária. As áreas de conhecimento aprovadas na Universidade do Panamá são quatro: Ciências Econômicas e Administrativas; Ciências da Saúde; Ciências Sociais, Humanísticas e Culturais; Ciências Naturais, Exatas e Tecnológicas. Com a inclusão de todas as unidades acadêmicas de acordo com sua área disciplinar em pesquisa, pós-graduação e licenciatura. A Vice-Reitoria de Pesquisa e Pós-Graduação, em 25 anos com o desenvolvimento de programas de pós-graduação, alcançou um total de 41.969 graduados, destacando-se com 91,6% dos egressos de programas desenvolvidos na Cidade Universitária, dos quais 43,7% no período de 1990 a 2000, 14,9% no período de 2001 a 2006 e 33% de 2007 a 2014, a maioria do sexo feminino. Ao classificá-los por áreas de conhecimento estabelecidas na Universidade do Panamá, observou-se maior percentual (74,4%) na área de Ciências Sociais, Humanísticas e Culturais. Seguido por 11,5% da área de Ciências Econômicas e Administrativas, 8,7% da área de Ciências da Saúde e 5,4% da área de Ciências Naturais, Exatas e Tecnológicas.

Effect of Nanoparticles on Modified Screen Printed Inhibition Superoxide Dismutase Electrodes for Aluminum.

A novel amperometric biosensor for the determination of Al(III) based on the inhibition of the enzyme superoxide dismutase has been developed. The oxidation signal of epinephrine substrate was affected by the presence of Al(III) ions leading to a decrease in its amperometric current. The immobilization of the enzyme was performed with glutaraldehyde on screen-printed carbon electrodes modifiedwith tetrathiofulvalene (TTF) and different types ofnanoparticles. Nanoparticles of gold, platinum, rhodium and palladium were deposited on screen printed carbon electrodes by means of two electrochemical procedures. Nanoparticles were characterized trough scanning electronic microscopy, X-rays fluorescence, and atomic force microscopy. Palladium nanoparticles showed lower atomic force microscopy parameters and higher slope of aluminum calibration curves and were selected to perform sensor validation. The developed biosensor has a detection limit of 2.0 ± 0.2 µM for Al(III), with a reproducibility of 7.9% (n = 5). Recovery of standard reference material spiked to buffer solution was 103.8% with a relative standard deviation of 4.8% (n = 5). Recovery of tap water spiked with the standard reference material was 100.5 with a relative standard deviation of 3.4% (n = 3). The study of interfering ions has also been carried out.

Acetylcholinesterase inhibition-based biosensor for aluminum(III) chronoamperometric determination in aqueous media.

A novel amperometric biosensor for the determination of Al(III) based on the inhibition of the enzyme acetylcholinesterase has been developed. The immobilization of the enzyme was performed on screen-printed carbon electrodes modified with gold nanoparticles. The oxidation signal of acetylthiocholine iodide enzyme substrate was affected by the presence of Al(III) ions leading to a decrease in the amperometric current. The developed system has a detection limit of 2.1 ± 0.1 µM for Al(III). The reproducibility of the method is 8.1% (n = 4). Main interferences include Mo(VI), W(VI) and Hg(II) ions. The developed method was successfully applied to the determination of Al(III) in spiked tap water . The analysis of a certified standard reference material was also carried out. Both results agree with the certified values considering the respective associated uncertainties.

Neurotoxicidad y enfermedades óseas provocadas por la contaminación con aluminio de soluciones de diálisis renal / Neuronal damage and bone diseases caused by the contamination with aluminum of solutions of renal dyalisis

En este artículo se revisan las principales evidencias de la neurotoxicidad in vitro del aluminio, y algunos hallazgos en cerebros de pacientes de la enfermedad de Alzheimer, se muestran algunos estudios realizados con pacientes que sufren deficiencias renales, como los tipos más importantes de ostodistrofias causados por aluminio. El problema de analizar la baja concentración de aluminio presente en fluidos humanos se resuelve con métodos analíticos muy sensibles como la espectrofotometría electrotérmica de absorción atómica ETAS, y métodos voltamperométricos con agentes acomplejantes; que permiten adsorción sobre electrodos sólidos o de gota suspendida de mercurio. Es muy importante conocer con exactitud la concentración de aluminio en agua usada en para preparar las disoluciones usadas en la hemodiálisis, o en las disoluciones usadas en la diálisis peritoneal ambulatoria, como primer paso para evitar la contaminación de los pacientes con aluminio. La prevención de la contaminación durante el muestreo, almacenaje y análisis de fluidos dializados es prioritaria y el agua usada en diálisis debe ser tan baja como sea posible en contenido de por aluminio.

This article reviews the principal evidences about aluminum neurotoxicity in vitro, and some evidences in brain tissues of Alzheimer patients; and also show some studies realized with humans that suffer renal deficiencies, dealing with the principal osteodystrophy. The problem of analyzing low aluminum concentration in human fluids is overcomed with very sensitive analytical methods as Electrothermal Atomic Absorption Spectrometry (ETAS) and voltammetric methods as Anodic Striping Voltammetry with complexing agents that easing adsorption over solid electrodes or mercury hanging drop. Is a vital question to know with accuracy the aluminum concentration in water used in hemodialysis or in fluids used in ambulatory peritoneal dialysis, as a first stage to prevent contamination by aluminium. So the prevention of contamination during sampling, storage and analysis of biological fluids should be the first need and the sources of water used in renal dialysis keep be as clean as possible of aluminium contamination.