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Lateral flow immunochromatography is a widely used technique for immunological assays. Construction of test and control lines is mostly done by antigen adsorption to nitrocellulose membranes, a process not fully understood. This study aimed to evaluate the influence of urea, salts, and Tween 20, on adsorption. The performance of canine IgG in water and in buffer containing urea and salts (pH 8.3) were compared to observe if the interferents would lead to protein stripping when challenged with increasing concentrations of Tween 20 in the lateral flow buffer. Immobilization of the rLiNTPDase2, an antigen for Canine Leishmaniasis diagnosis, was evaluated and compared to the rLbNTPDase2 by the same method. There were no differences between adsorption coefficients of IgG in water and in buffer, but high salt and urea concentrations seems to stabilize and enhance IgG immobilization. Adsorption performance between canine IgG and rNTPDases had different patterns, but was highly similar between rNTPDases, indicating that protein identity may have an important role. Also, low concentrations of Tween 20 in the flow solution may aid the maintenance of rNTPDase2 on the strips. Our results bring insights about protein adsorption and perspectives about the influence of urea, salts and Tween 20 on this process.

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The aim of this study was to develop an assay to analyze the serum profile of Mannose-binding lectin (MBL) through a simple and "in-house" method (called "dot-N-man"). Furthermore, the study attempted to associate molecular masses of MBL to the profile of MBL gene polymorphisms in patients with hepatitis C. Heterogeneity in molecular masses of MBL is due to the impairment of oligomers formation, which is linked to genetic polymorphisms in the MBL gene. Individuals with AA genotype (wild-type) produce high-molecular-mass proteins, whereas AO and OO individuals produce intermediate and low-molecular-mass proteins, respectively. Sera of thirty patients carrying the hepatitis C virus (HCV) were investigated using MBL binding assay with mannan-coated nitrocellulose (dot-N-man). Purified MBL was evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. Dot-N-Man assay yielded MBL with molecular masses ranging between 55 and 320 kDa, comparable to low and high molecular mass forms of MBL. Nonreducing SDS-PAGE showed high molecular mass bands in all AA individuals while bands of 270 and 205 kDa were observed in sera for a number of patients with AO and OO genotypes, respectively. Immunoblotting confirmed the MBL samples obtained from the dot-N-man. These results provide new insights to understand the MBL molecular forms profile in patients infected with HCV- which could be useful in future investigations on the influence of the MBL structure/genotype on both the progression of infection and the response to hepatitis C therapy.

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The immunoblotting reaction for performing the paracoccidioidomycosis (PCM) immunodiagnosis is an in-house methodology; and being a laborious task involving two previous steps, SDS-PAGE and Western blot, we evaluated the shelf life of nitrocellulose membranes containing the immobilized P. brasiliensis antigens, stored at -20 o C for 7, 15, 30, 45, 60 and 90 days. Twenty-eight serum samples were analyzed on two nitrocellulose membranes groups: (a) membranes previously blocked with PBS-5 % non-fat dry milk and (b) the priory non-blocked membranes. No difference was detected in the reactivity pattern in serum samples evaluated in the both membrane groups, especially for those stored for 7, 15, 30, 45 and 60 days. It might be emphasized that a good stability of P. brasiliensis antigens, immobilized on the nitrocellulose membranes, enable them to be stored up to 60 days at -20 o C. This finding contributes to the rapid diagnosis of PCM, and for sending them to other laboratories without adequate infrastructure for carrying out the steps that precede the immunodetection as the antigen production, SDS-PAGE and Western blot techniques. This scheme contributes substantially to improve the quality of PCM serodiagnosis, as it provides reproducible results in the units of the Laboratory Network.(AU)

Considerando-se que o immunoblotting para o imunodiagnóstico da paracoccidioidomicose (PCM) é uma metodologia in house e laboriosa envolvendo duas etapas iniciais, SDS-PAGE e Western blot, neste estudo foi avaliado o tempo de prateleira das membranas de nitrocelulose sensibilizadas com antígeno de P. brasiliensis, armazenadas a -20 o C durante 7, 15, 30, 45, 60 e 90 dias. Vinte e oito amostras de soro foram analisadas em dois grupos de membranas de nitrocelulose (membranas previamente bloqueadas com PBS-leite 5 % e as não-bloqueadas). Não houve diferença no padrão de reatividade quando os soros foram avaliados frente a ambos os grupos, especialmente para membranas armazenadas por 7, 15, 30, 45 e 60 dias. A boa estabilidade do antígeno utilizado para sensibilizar as membranas fez com que estas pudessem ser armazenadas a -20 C até 60 dias. Estas características contribuem para efetuar o diagnóstico rápido da PCM, bem como as perspectivas dessas membranas sensibilizadas serem encaminhadas para os laboratórios, que não possuam infraestrutura necessária para executar as etapas que antecedem a realização de immunoblotting, como a produção de antígeno, as técnicas de SDS PAGE e Western blot. Este procedimento contribui substancialmente para melhorar o diagnóstico sorológico da PCM, pois poderá fornecer resultados reprodutíveis nas unidades componentes da Rede de Laboratórios.(AU)

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Bactericidal water filters were developed. For this purpose, nitrocellulose membrane filters were impregnated with different biosynthesized silver nanoparticles. Silver nanoparticles (AgNPs) from Aspergillus niger (AgNPs-Asp), Cryptococcus laurentii (AgNPs-Cry) and Rhodotorula glutinis (AgNPs-Rho) were used for impregnating nitrocellulose filters. The bactericidal properties of these nanoparticles against Escherichia coli, Enterococcus faecalis and Pseudomona aeruginosa were successfully demonstrated. The higher antimicrobial effect was observed for AgNPs-Rho. This fact would be related not only to the smallest particles, but also to polysaccharides groups that surrounding these particles. Moreover, in this study, complete inhibition of bacterial growth was observed on nitrocellulose membrane filters impregnated with 1 mg L(-1) of biosynthesized AgNPs. This concentration was able to reduce the bacteria colony count by over 5 orders of magnitude, doing suitable for a water purification device.

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In this paper we explore the direct transfer via lamination of chemical vapor deposition graphene onto different flexible substrates. The transfer method investigated here is fast, simple, and does not require an intermediate transfer membrane, such as polymethylmethacrylate, which needs to be removed afterward. Various substrates of general interest in research and industry were studied in this work, including polytetrafluoroethylene filter membranes, PVC, cellulose nitrate/cellulose acetate filter membranes, polycarbonate, paraffin, polyethylene terephthalate, paper, and cloth. By comparing the properties of these substrates, two critical factors to ensure a successful transfer on bare substrates were identified: the substrate's hydrophobicity and good contact between the substrate and graphene. For substrates that do not satisfy those requirements, polymethylmethacrylate can be used as a surface modifier or glue to ensure successful transfer. Our results can be applied to facilitate current processes and open up directions for applications of chemical vapor deposition graphene on flexible substrates. A broad range of applications can be envisioned, including fabrication of graphene devices for opto/organic electronics, graphene membranes for gas/liquid separation, and ubiquitous electronics with graphene.

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The present study evaluated the toxic potential and physicochemical characteristics of waste water generated in nitrocellulose production, including effluents from delignification, bleaching, nitration and mixture (composed of these three effluents), from a plant in the Paraiba Valley, São Paulo, Brazil. The test organisms used for toxicity assays were Daphnia similis, Danio rerio, Escherichia coli, Pseudomonas putida and Pseudokircheneriella subcaptata. The results showed that the effluents analyzed present acute and chronic toxicity for the organisms tested. Nitration effluent was the least toxic, while delignification and bleaching effluents were the most toxic. The naturally occurring pollutants in wood fiber and cotton, like lignin, probably contributed to effluents toxicity, in addition to higher concentrations of total dissolved solids, which are in non-compliance with Brazilian legislation, conductivity, chemical oxygen demand and color. The discharge of nitrocellulose effluent into an aquatic environment should only occur after appropriate treatment, due to their toxic characteristics.

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Introducción: la inmovilización de antígenos a soportes sólidos se utiliza para el desarrollo de diversos inmunoensayos. Una de las primeras tecnologías desarrolladas fue la adsorción de proteínas por aplicación directa sobre la nitrocelulosa. Objetivo: normalizar la inmovilización de un péptido sintético de la proteína de transmembrana gp36 del VIH-2, a un soporte de nitrocelulosa para fines diagnósticos y evaluar los parámetros de desempeño en un grupo de muestras de sueros con reactividad de interés conocida. Métodos: el péptido se inmovilizó de forma libre, conjugado a la albúmina de suero bovina (BSA) y a la hemocianina de lapa marina (KLH) como proteínas portadoras. Se analizaron los parámetros de inmovilización y se determinó la variante óptima. Con la variante escogida se evaluó la sensibilidad y especificidad diagnóstica frente a paneles de referencia del Laboratorio de Investigaciones del SIDA. La especificidad analítica se evaluó con muestras reactivas a VIH-1 y HTLV-I. Resultados: el análisis de las variantes de péptido inmovilizadas a las membranas de nitrocelulosa, demostró que el péptido gp36-BSA, fue el que logró la mayor diferenciación entre muestras positivas y negativas. Se obtuvo 100 por ciento de sensibilidad y 95,2 por ciento de especificidad diagnóstica, así como 100 por ciento de especificidad analítica. Conclusiones: el péptido gp36-BSA inmovilizado en membranas de nitrocelulosa es eficaz en el diagnóstico serológico del VIH-2, lo cual permitirá considerarlo para su empleo con fines diagnósticos en sistemas que utilicen como fase sólida la nitrocelulosa.

Introduction: antigen immobilization in solid supports is used for the development of several immunoassays. One of the first technologies developed was the protein adsorption by direct application to nitrocellulose. Objective: to standardize the immobilization of a synthetic peptide of the HIV-2 transmembrane protein gp36 to nitrocellulose support for diagnostic purposes and to evaluate the performance parameters in a group of serum samples with recognized interesting reactivity. Methods: the peptide was freely immobilized, conjugated to bovine serum albumin (BSA) and to keyhole limpet hemocyanin (KLH) as carrier proteins. Immobilization parameters were analyzed and then, the optimal immobilization alternative was determined. Using the chosen variant, the diagnostic sensitivity and specificity against reference panels of the AIDS Research Laboratory were evaluated. Analytical specificity was evaluated with reactive samples to HIV-1 and HTLV-I. Results: the analysis of the immobilized peptide variants to nitrocellulose membranes showed that the gp36 peptide-BSA was the one that succeeded in setting the greatest differentiation between positive and negative samples. There were observed 100 percent sensitivity, 95.2 percent diagnostic specificity and 100 percent analytical specificity. Conclusions: the gp36-BSA peptide immobilized on nitrocellulose membranes showed efficacy for the serological diagnosis of HIV-2, which will allow considering this peptide for diagnostic uses in systems with nitrocellulose based solid phase.

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INTRODUCTION: antigen immobilization in solid supports is used for the development of several immunoassays. One of the first technologies developed was the protein adsorption by direct application to nitrocellulose. OBJECTIVE: to standardize the immobilization of a synthetic peptide of the HIV-2 transmembrane protein gp36 to nitrocellulose support for diagnostic purposes and to evaluate the performance parameters in a group of serum samples with recognized interesting reactivity. METHODS: the peptide was freely immobilized, conjugated to bovine serum albumin (BSA) and to keyhole limpet hemocyanin (KLH) as carrier proteins. Immobilization parameters were analyzed and then, the optimal immobilization alternative was determined. Using the chosen variant, the diagnostic sensitivity and specificity against reference panels of the AIDS Research Laboratory were evaluated. Analytical specificity was evaluated with reactive samples to HIV-1 and HTLV-1. RESULTS: the analysis of the immobilized peptide variants to nitrocellulose membranes showed that the gp36 peptide-BSA was the one that succeeded in setting the greatest differentiation between positive and negative samples. There were observed 100 % sensitivity, 95.2 % diagnostic specificity and 100 % analytical specificity. CONCLUSIONS: the gp36-BSA peptide immobilized on nitrocellulose membranes showed efficacy for the serological diagnosis of HIV-2, which will allow considering this peptide for diagnostic uses in systems with nitrocellulose -based solid phase.

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La campilobacteriosis constituye una de las enfermedades diarreicas más frecuentes en el hombre, causada principalmente por consumo de alimentos. El diagnóstico tradicional, ampliamente utilizado, es el cultivo microbiológico, el cual necesita de al menos 48 horas para poder ser reportado, además de necesitar de ciertas condiciones especiales de cultivo. Actualmente existen diferentes pruebas diagnosticas para la detección de Cempytobecter spp, como los ensayos inmunoenzimáticos tipo ELlSA y pruebas más sofisticadas como la “Polymerase Chain Reaction” (PCR) (24, 25, 26, 27). El test de dot-ELlSA es una prueba inmunoenzimática que hasta el momento no ha sido adaptada para el diagnóstico de Campylobacter spp, considerándosele una buena alternativa para su uso debido al poco requerimiento de insumos para su aplicación, especialmente en laboratorios que no cuentan con la infraestructura necesaria para realizar un cultivo de Campylobacter spp o estudios de ELlSA. El trabajo, desarrollado constituyó el diseño de un dot-ELlSA para la detección de coproantígenos de Campylobacter en heces humanas, estableciendo la sensibilidad analítica y la sensibilidad y especificidad epidemiológica del ensayo. Para esto se utilizó muestras de pacientes del Instituto Nacional del Niño (INSN), en el periodo de Marzo-Agosto 2010. El presente estudio es de tipo descriptivo, observacional y de corte transversal. El criterio de muestreo utilizado fue por conveniencia, terminando el proceso de recolección al momento de finalizar el número de muestras preestablecidas. El análisis de datos se llevo a cabo mediante el uso de la tabla 2 x 2. Se analizó un total de 72 muestras, diez muestras positivas al cultivo de Campylobacter spp (13.89 por ciento), 12 muestras con diagnostico microbiológico para otros enteropatógenos bacterianos (16.67 por ciento), y 50 muestras con cultivo microbiológico negativo para cualquier entero patógeno bacteriano (69.44 por ciento). La sensibilidad analítica del ensayo fue de aproximadamente 332.3ng/ml, con una sensibilidad diagnóstica del 100 por ciento Y especificidad del 95.16 por ciento. En el se estudio se concluye que el ensayo dot-ELlSA no debe sustituir el cultivo microbiológico, sin embargo constituye una técnica alternativa con alta sensibilidad y especificidad para el diagnostico rápido de campilobacteriosis (150 minutos). Futuros estudios son necesarios para colectar mayor información relacionada con la detección de coproantígenos de Campylobacter, recomendándose el análisis de un mayor número de muestras y el análisis de un mejor gold están dar como prueba de referencia debido a la menor sensibilidad del cultivo con respecto a pruebas más sofisticadas como el PCR

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The objective of this work was to characterize the delignification effluent originating from the delignification industry and evaluate the combination of the fungus and photocatalytic process (TiO(2)/UV system) for the treatment of this effluent. The delignification effluent has proven harmful to the environment because it presents high color (3516 CU), total phenol (876 mg/L) and TOC (1599 mg/L) and is also highly toxic even in a low concentration. The results of photocatalysis were 11%, 25% and 13% higher for reductions in color, total phenol and TOC, respectively. The combined treatments presented benefits when compared to the non-combined treatments. Fungus and photocatalysis in combination proved to be the best treatment, reducing the color, total phenol, toxicity (inhibition of Escherichia coli growth) and TOC by 94.2%, 92.6%, 4.9% and 62%, respectively.

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