Publications by authors named "Tiago A Silva"

Phenolic compounds exhibit potent antioxidant properties and defense mechanisms in plants, serving as quality biomarkers. This study investigates the effect of chitosan formulations, incorporated with 1 % and 2 % ascorbic acid and quercetin, for extending cassava shelf life and improving nutritional quality. The PhotoMetrix® smartphone App was employed to analyze the impact of these treatment-formulations on their total phenolic contents (TPC) using RGB (Red-Green-Blue) color scale, validated by statistical analysis.

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Fibroepithelial polyps (FEPs) are rare benign tumors that can occur in the urinary tract and are especially uncommon in the urethra. This report presents a case of a young man with obstructive symptoms caused by a urethral polyp, which was treated endoscopically. Fibroepithelial polyps can be a cause of urethral stenosis in young men and may also be encountered during the treatment of other causes of urethral narrowing.

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An overview of the latest advances in the design of electrochemical sensor architectures dedicated to the determination of drugs from the statin class is presented in this review. Statins are drugs widely consumed for cholesterol control, and their determination in different matrices through the application of electroanalysis is growing considering advantages such as operational simplicity, lower cost and ease of sample preparation. Within the context of statins, electrochemical sensor architectures can be subdivided into conventional/classical electrodes such as glassy carbon electrodes, carbon paste electrodes, pencil graphite electrodes, boron-doped diamond electrodes and metallic electrodes, and more modern electrode systems, including the screen-printed electrodes and 3D-printed electrodes.

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Rapid virus identification is crucial for preventing outbreaks. The COVID-19 pandemic has highlighted the critical nature of rapid virus detection. Here, we designed a label-free electrochemical biosensor modified with gold nanoparticles (AuNPs) to detect IgG antibodies from human serum, enabling rapid point-of-care diagnostics.

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Contributing to the development of sustainable electroanalytical chemistry, electrochemically reduced graphene oxide (ERGO) films obtained from residual graphite of discharged Zn-C batteries are proposed in this work. Graphite from the cathode of discarded Zn-C batteries was recovered and used in the synthesis of graphene oxide (GO) by the modified Hummer's method. The quality of the synthesized GO was verified using different characterization methods (FT-IR, XRD, SEM, and TEM).

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Electrochemical sensors consisting of screen-printed electrodes (SPEs) are recurrent devices in the recent literature for applications in different fields of interest and contribute to the expanding electroanalytical chemistry field. This is due to inherent characteristics that can be better (or only) achieved with the use of SPEs, including miniaturization, cost reduction, lower sample consumption, compatibility with portable equipment, and disposability. SPEs are also quite versatile; they can be manufactured using different formulations of conductive inks and substrates, and are of varied designs.

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The versatility of chitosan (Ch) biopolymer as a metallic nanoparticle stabilizing agent and excellent former of thin films on glassy carbon was explored in this work for the sustainable manufacture of novel electrochemical sensors based on carbon black (CB) and chitosan-stabilized platinum nanoparticles (Ch-PtNPs). Platinum nanoparticles highly stabilized by chitosan were easily synthesized at room temperature and characterized by HR-TEM, UV-vis, and voltammetry. Ch-PtNPs presented an average diameter of 2.

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The environment where plants grow, such as acidic soils, interferes with the nutrient concentration and physiological quality of seeds. This hypothesis was tested using wheat seeds as a model crop, grown in a tropical soil with and without lime application for twelve years. Here we show that lime provides remarkable enhancements in soil chemistry and seed composition, without altering the seed's germination and vigor.

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The outstanding electronic properties of carbon black (CB) and its economic advantages have fueled its application as nanostructured electrode material for the development of new electrochemical sensors and biosensors. CB-based electrochemical sensing devices have been found to exhibit high surface area, fast charge transfer kinetics, and excellent functionalization. In the present work, we set forth a comprehensive review of the recent advances made in the development and application of CB-based electrochemical devices for pharmaceutical and biomedical analyses - from quantitative monitoring of drug formulations to clinical diagnoses - and the underlying challenges and constraints that need to be overcome.

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Retroperitoneal hemorrhage is a rare and life-threatening clinical presentation that may occur in patients with advanced germ cell tumors, typically after chemotherapy. Rapid clinical suspicion is crucial to offer the best treatment. Surgery is usually recommended but dismal complications may occur.

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A modified glassy carbon electrode with carbon black (CB) and gold nanoparticles (AuNPs) within a crosslinked chitosan (CTS) film is proposed in this work. The electroanalytical performance of the modified CB-CTS-AuNPs/GCE has been evaluated towards the voltammetric sensing of ketoconazole (KTO), a widespread antifungal drug. The nanocomposite was characterized by scanning electron microscopy, X-ray diffraction spectroscopy, and electrochemistry experiments.

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For the development of drugs that treat SARS-CoV-2, the fastest way is to find potential molecules from drugs already on the market. Unfortunately, there is currently no specific drug or treatment for COVID-19. Among all structural proteins in SARS-CoV, the spike protein is the main antigenic component responsible for inducing host immune responses, neutralizing antibodies, and/or protecting immunity against virus infection.

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A case report of a 51-year-old man with left renal tumor and level II vena cava tumor thrombus (thrombus extending >2 cm above the renal vein, but below the hepatic veins) in a rare anatomical variant of renal vein. In nonmetastatic patients, aggressive surgical resection is widely accepted as the standard management option, but some doubts about the best practice in these patients are relevant. Surgical approach on those patients is a challenge for the surgeons, and anatomical variants make the procedure even more difficulty.

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The detection of phenolic compounds is relevant not only for their possible benefits to human health but also for their role as chemical pollutants, including as endocrine disruptors. The required monitoring of such compounds on-site or in field analysis can be performed with electrochemical biosensors made with polyphenol oxidases (PPO). In this review, we describe biosensors containing the oxidases tyrosinase and laccase, in addition to crude extracts and tissues from plants as enzyme sources.

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Bladder cancer (BC) is classified into non-muscle (NMIBC) and muscle invasive (MIBC) diseases. Several molecular alterations were previously associated with NMIBC and MIBC, but few studies have systematically compared the molecular differences between these subtypes. Here, we analyzed prognostic and differentially expressed genes in NMIBC and MIBC, using an integrative bioinformatics approach.

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The ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate and carbon black (CB) nanoparticles were incorporated within a crosslinked chitosan film over the surface of a glassy carbon electrode, and the obtained architecture explored to the sensitive voltammetric sensing of Allura red colorant in soft drinking powders. The different electrodic surfaces were morphologically and electrochemically characterized. From the modification of glassy carbon electrode with IL and CB, a significantly enhanced voltammetric response was achieved toward the Allura red irreversible oxidation reaction.

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A low-cost and disposable microcell was constructed with a screen-printed electrode for the non-enzymatic electrochemical determination of creatinine. The working electrode was modified with carbon black and maintained in contact with paper-adsorbed iron (III) ions. A small sample volume of 3 μL was required for the device operation.

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A disposable microfluidic electrochemical paper-based device for multiplexed analysis based on sixteen independent microfluidic channels with electrochemical detection is proposed. A major advantage of this work was the non-necessary use of a wax printer for devices manufacturing which has a high cost of operation. In addition, a commercial multiplexing module was used that has the multiplexing capability of 8-16 channels and, for the first time using this module, the strategy of multiplexing both the working and reference electrodes were used.

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Carbon Black (CB) has acquired a prominent position as a carbon nanomaterial for the development of electrochemical sensors and biosensors due to its low price and extraordinary electrochemical and physical properties. These properties are highly dependent on the surface chemistry and thus, the effect of functionalization has been widely studied for different applications. Meanwhile, the influence of CB functionalization over its properties for electroanalytical applications is still being poorly explored.

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We explored the use of carbon black (CB), graphene oxide (GO), copper nanoparticles (CuNPs) and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as electrode materials for the simultaneous determination of isoproterenol, acetaminophen, folic acid, propranolol and caffeine. The designed nanostructured surface was widely characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), contact angle measurements and electrochemistry. From electrochemical characterization assays carried out towards the potassium ferricyanide redox probe, fast electron transfer kinetics and a considerably higher electroactive surface area were observed for the modified electrodic surface based on CB, GO, CuNPs and PEDOT:PSS film.

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New insights into the design of highly sensitive, carbon-based electrochemical sensors are presented in this work by exploring the interesting properties of graphene oxide (GO) and ionic liquids (ILs). An electrochemical sensor based on the carbon paste electrode (CPE) modified with GO and IL was developed for the sensitive detection of ofloxacin using square-wave adsorptive anodic stripping voltammetry (SWAdASV). GO sheets were obtained from the acid treatment of graphene and characterized by scanning and transmission electronic microscopy (SEM and TEM) and selected area electron diffraction (SAED), and the electrochemical behavior of the modified GO-IL/CPE was explored by electrochemical impedance spectroscopy studies.

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Advances in analysis are required for rapid and reliable clinical diagnosis. Graphene is a 2D material that has been extensively used in the development of devices for the medical proposes due to properties such as an elevated surface area and excellent electrical conductivity. On the other hand, architectures have been designed with the incorporation of different biological recognition elements such as antibodies/antigens and DNA probes for the proposition of immunosensors and genosensors.

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Porous diamond-like carbon (DLC) electrodes have been prepared, and their electrochemical performance was explored. For electrode preparation, a thin DLC film was deposited onto a densely packed forest of highly porous, vertically aligned multiwalled carbon nanotubes (VACNT). DLC deposition caused the tips of the carbon nanotubes to clump together to form a microstructured surface with an enlarged surface area.

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