Papers by Marcos Vinicius Foguel
Biosensors
An electrochemical immunosensor based on a nanohybrid film of carboxylated polypyrrole and amine ... more An electrochemical immunosensor based on a nanohybrid film of carboxylated polypyrrole and amine nanoclay was developed for label-free detection of the human cardiac troponin T (cTnT). The nanohybrid film was formed in situ on the surface of the glassy carbon electrode, followed by the covalent immobilization of anti-troponin T antibodies by glutaraldehyde. Morphological and chemical characterizations of the nanohybrid film were performed by scanning electron microscopy and Fourier-transform infrared spectroscopy. Under the optimized conditions, a calibration curve for cTnT in spiked serum was obtained by square wave voltammetry, and a low limit of detection and quantification was achieved (0.35 and 1.05 pg mL−1, respectively). This was the first time that this type of nanohybrid film was used in the development of an immunosensor for cTnT that proved to be a simple and efficient strategy for the manufacture of a label-free electrochemical device that could be applied in the diagnos...
Chagas disease has been spread mainly through blood transfusion or blood components, therefore th... more Chagas disease has been spread mainly through blood transfusion or blood components, therefore the development of a device for neglected diseases with high specificity and sensitivity is important to public health. This work de-scribes the development of an amperometric immunosensor for determination of Chagas disease through a gold-based electrode obtained from a recordable compact disc modified with 4-(methylmercapto)benzaldehyde for the immobilization of Tc85 protein of the Trypanosoma cruzi. The immunoassays were carried out using positive and negative sera from Chagasdisease patients and immunoglobulin conjugated with peroxidase enzyme. The immuno-sensor presented 0.949 mA as cut-off value and was applied in sera samples.
Biosensors based on DNA or RNA aptamers, represent a very efficient platform for protein recognit... more Biosensors based on DNA or RNA aptamers, represent a very efficient platform for protein recognition1. We developed a novel label-free aptamer biosensing array for thrombin detection by measuring the electrochemical impedance upon aptamer-protein complex formation using gold CD-trodes (GCDT). GCDT are electrodes fabricated from recordable compact discs that contain a fine gold layer on their surface. Low-cost GCDTs present good versatility and acceptable reproducibility. The thrombin biosensor is constructed by self-assembling a thiol-modified aptamer onto a GCDT surface, followed by recognition of the protein via monitoring the interfacial electron transfer resistance in the presence of an [Fe(CN)6]3-/4- redox couple2,3. The aptasensor was also characterized by cyclic voltammetry and the individual binding steps were analysed by scanning electron microscopy.
ECS Meeting Abstracts, 2021
Procedia Technology, 2017
An alternative for determination of dyes is the biomimetic sensors development with optical trans... more An alternative for determination of dyes is the biomimetic sensors development with optical transduction, employing molecularly imprinted polymers (MIP) as recognition system. This work shows the MIP synthesis for the textile dye Acid Green 16 and the results of rebinding, selectivity and application of this MIP in textile effluent. The imprinted polymer presented rebinding of 83% and imprinted factor of 6.91, great selectivity and recovery next to 100%. Due to the excellent performance of this MIP, it can be a promising synthetic recognizer in the development of optical biomimetic sensors based on optical fibers.
Sensors and Actuators B: Chemical, 2017
An electrochemical sensor based on molecularly imprinted polymer (MIP) film for dodecyl gallate d... more An electrochemical sensor based on molecularly imprinted polymer (MIP) film for dodecyl gallate detection at the surface of a glassy carbon electrode (GCE) was proposed in this paper. The GCE was modified with f-MWCNT and the MIP synthesis was performed in situ by means of electropolymerization using ortho-phenylenediamine as the monomer. The stepwise preparation of the MIP and NIP (non-imprinted polymer) was characterized electrochemically by means of cyclic and square wave voltammetry employing ferrocyanide/ferricyanide as a redox probe. The selective capacity performance of the MIP and its imprinted effect to the template molecule (analyte) was compared to the NIP. They were also characterized by scanning electron microscopy technique (SEM). The analytical performance of the MIP sensor performed using square wave voltammetry showed linear range from 0.50 to 8.0 × 10 −9 mol L −1 , with a correlation coefficient of 0.9921. The sensor presented detection and quantification limit of 0.22 × 10 −9 and 0.67 × 10 −9 mol L −1 , respectively. The apparent dissociation constant (K D) calculated was of 1.26 × 10 −4 mol L −1 and 5.27 × 10 −1 mol L −1 for the MIP and NIP respectively.
Chemosensors, 2016
This work describes the investigation of a label-free immunosensor for the detection of aflatoxin... more This work describes the investigation of a label-free immunosensor for the detection of aflatoxin B 1 (AFB 1). CD-trodes (electrodes obtained from recordable compact disks) were used as low-cost and disposable transducers after modification with a self-assembled monolayer (SAM) of lipoic acid. The anti-aflatoxin B 1 antibody was immobilized via EDC/NHS activation, followed by blocking with bovine serum albumin and immunoassays with AFB 1. The optimization of analytical parameters and the detection were carried out using electrochemical impedance measurements. Using chemometric tools, the best conditions for the immunosensor development were defined as: anti-AFB 1 antibody at 1:2000 dilution and surface blocking with 0.5% bovine serum albumin, both incubated for 1 h, and antibody-antigen immunoreaction for 30 min. The impedimetric immunosensor showed a linear range from 5 × 10 −9 to 1 × 10 −7 mol•L −1 (1.56-31.2 ng•mL −1), limit of detection and limit of quantification, respectively, 3.6 × 10 −10 and 1.1 × 10 −9 mol•L −1 (0.11 and 0.34 ng•mL −1). The proposed immunosensor was applied to analyze peanut samples.
Journal of the Brazilian Chemical Society, 2015
The construction of gold electrodes using 3 kinds of gold recordable compact discs (CDtrodes) and... more The construction of gold electrodes using 3 kinds of gold recordable compact discs (CDtrodes) and characterization by electrochemical and spectroscopic techniques are herein reported. Following a surface pretreatment in 0.5 mol L −1 sulfuric acid (H 2 SO 4), the electrochemical experiments were performed in the presence of redox couple ferro/ferricyanide [Fe(CN) 6 ] 3−/4−. The immobilization of an oligopeptide bio-inspired by acetylcholinesterase onto the CDtrode was also evaluated. Surface characterization was done by cyclic voltammetry, electrochemical impedance spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy and atomic force microscopy. CDtrodes are known to be of low cost, fast and simple construction. They are suitable for immobilizing biological molecules and could be used as disposable transducer for the construction of biosensors.
Sensors and Actuators B: Chemical, 2015
A cheap and robust method for the detection and quantification of textile dyes is the use of biom... more A cheap and robust method for the detection and quantification of textile dyes is the use of biomimetic sensors with optical transduction, employing a molecularly imprinted polymer (MIP) as the recognition element. This paper presents the optimization of a MIP for the dye, basic red 9 (BR9) and the immobilization of these polymers on a disposable 4-cm long polystyrene optical waveguide for the development of an evanescent wave fiber optic sensor aimed at the determination and quantification of this dye in different matrices and industrial effluents. MIPs were synthesized using 2-acrylamido-2-methyl-1-propanesulfonic acid and ethylene glycol dimethacrylate, as functional monomer and cross-linker, respectively. The polymer was then immobilized on the waveguide by dip-coating the fiber in the polymer suspension. The sensing element was interrogated with a fiber-coupled spectrophotometer. BR9 could be detected in the low M range, thus making it a promising device for determining this compound in textile effluents.
Eclética Química, 2009
Os eletrodos de ouro são largamente utilizados em estudos eletroquímicos e eletroanalíticos, devi... more Os eletrodos de ouro são largamente utilizados em estudos eletroquímicos e eletroanalíticos, devido à sua elevada pureza, ampla faixa de potencial de trabalho, bem como a possibilidade de controle e modificação da superfície eletródica. Neste trabalho são descritos procedimentos para construção e limpeza de eletrodos a partir de CDs de ouro graváveis, denominados CDtrodos. Inicialmente, os CDs foram submetidos à ação de HNO3 concentrado para retirada da camada polimérica protetora e exposição da camada metálica, posteriormente, para a construção dos CDtrodos, delimitou-se a área eletródica com fita de galvanoplastia. Diversos métodos para a limpeza da superfície do ouro foram empregados, após ataque do HNO3, tais como, aplicação de potencial fixo em solução de NaCl, ciclagens sucessivas em H2SO4 e aplicação de ultra-som, sendo que os melhores resultados foram obtidos por tratamento com H2SO4. A literatura tem registrado vários trabalhos empregando CDtrodo no entanto são focados na a...
State of the Art in Biosensors - Environmental and Medical Applications, 2013
Electroanalysis, 2011
Chagas disease has been spread mainly through blood transfusion or blood components, therefore th... more Chagas disease has been spread mainly through blood transfusion or blood components, therefore the development of a device for neglected diseases with high specificity and sensitivity is important to public health. This work describes the development of an amperometric immunosensor for determination of Chagas disease through a goldbased electrode obtained from a recordable compact disc modified with 4-(methylmercapto)benzaldehyde for the immobilization of Tc85 protein of the Trypanosoma cruzi. The immunoassays were carried out using positive and negative sera from Chagasdisease patients and immunoglobulin conjugated with peroxidase enzyme. The immunosensor presented À0.949 mA as cutoff value and was applied in sera samples.
Journal of Materials Research and Technology, 2021
Abstract Ciprofloxacin is an antibiotic widely used in the treatment of human and animal diseases... more Abstract Ciprofloxacin is an antibiotic widely used in the treatment of human and animal diseases and can be found as a contaminant in some foods of animal origin, such as milk. Thus, the use of molecularly imprinted polymers based on magnetic nanoparticles (mag-MIP) has interesting advantages for extraction in complex samples. Mag-MIP selectivity is provided by careful selection of the functional monomer that will interact with specific groups of the model molecule. Thus, this work presents, for the first time, the performance comparison of mag-MIPs for ciprofloxacin that were synthesized using one functional monomer (mag-MIP1) the acrylic acid, as well as two functional monomers (mag-MIP2), using acrylic acid and 1-vinylimidazole. Both polymers were characterized using different techniques, and the conditions for rebinding the analyte to specific cavities were optimized. Mag-MIP2 showed faster rewiring of ciprofloxacin to polymeric cavities (30 min versus 120 min for mag-MIP1) and better selectivity. Both magnetic polymers were applied to samples of whole and skimmed milk and showed that the percentage range of ciprofloxacin adsorbed to mag-MIP1 was 47-98%, while that for mag-MIP2 was 87-99%. Therefore, mag-MIP synthesized with two functional monomers (mag-MIP2) showed a more promising performance to be applied in the extraction of ciprofloxacin in complex matrices, such as milk.
Analytical Chemistry, 2019
Sequences of the RNA/DNA Table S1. Oligonucleotides sequences* used in 4WJ-based biosensor and NA... more Sequences of the RNA/DNA Table S1. Oligonucleotides sequences* used in 4WJ-based biosensor and NASBA.
Journal of Applied Polymer Science, 2019
In the present study, a boundary-value problem corresponding to forced vibration of an imperfectl... more In the present study, a boundary-value problem corresponding to forced vibration of an imperfectly bonded bi-layered plate-strip resting on a rigid foundation is considered. In the framework of threedimensional linearized theory of elastic waves in initially stressed bodies, the mathematical modelling of considered problem is given. Then, the variational formulation of the problem considered is obtained in the framework of the principles of calculus of variation. The problem considered differs from the previous studies in the view of imperfect boundary conditions between the layers of the plate-stip and between the plate-strip and the rigid foundation.
Sensors and Actuators B: Chemical, 2019
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Papers by Marcos Vinicius Foguel