Publications by authors named "Tiago A Silva"

The genus Wittmackia has 44 species distributed in two centers of diversity: the Brazilian clade and the Caribbean clade. The Brazilian clade includes 29 species, with geographic distribution concentrated in the Northeast of Brazil. This study reports the morphology, ultrastructure, pollen viability and stigma receptivity by different microscopy techniques of 23 species of the genus Wittmackia endemic to Brazil and occurring in Atlantic Forest areas.

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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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Article Synopsis
  • Development of electroanalytical chemistry is advanced through using electrochemically reduced graphene oxide (ERGO) films made from recycled graphite from discarded Zn-C batteries.
  • The synthesis of graphene oxide (GO) was confirmed using multiple characterization techniques, and ERGO films displayed superior electrochemical properties when tested with various analytes.
  • The ERGO-based sensors demonstrated high analytical sensitivity and effectiveness in detecting compounds like paracetamol and hydroquinone in synthetic urine and tap water, making them a cost-effective, eco-friendly option for creating electrochemical sensors.
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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 study investigates the use of chitosan (Ch) as a stabilizing agent for platinum nanoparticles and a material for creating sensors on glassy carbon.
  • Chitosan-stabilized platinum nanoparticles (Ch-PtNPs) were synthesized and characterized, showing an average size of 2.7 nm, and demonstrated effective electrocatalytic activity for detecting hydrogen peroxide and the endocrine disruptor bisphenol A (BPA).
  • The developed sensors showed high sensitivity and accuracy, with detection limits of 10 μmol/L for hydrogen peroxide and 7.9 nmol/L for BPA, along with strong repeatability and reliability for analyzing natural water samples.
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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 (GCE) incorporating carbon black and gold nanoparticles within a chitosan film was developed for sensing ketoconazole (KTO), an antifungal drug.
  • The electrode demonstrated an irreversible oxidation process for KTO at +0.65 V and was characterized using various techniques including SEM and electrochemistry.
  • The method provided a linear detection range for KTO from 0.10 to 2.9 μmol L, with a low limit of detection (4.4 nmol L) and was effectively used to analyze KTO in pharmaceutical and biological samples.
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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 cost-effective, disposable microcell was developed for measuring creatinine levels using a modified screen-printed electrode that incorporates carbon black and iron (III) ions.
  • The device requires only a tiny sample volume of 3 μL and works through a method involving the complexing of iron (III) ions with creatinine, followed by electrochemical analysis.
  • The sensor demonstrated a reliable linear response for creatinine concentrations between 0.10 and 6.5 mmol/L, with a detection limit of 0.043 mmol/L, and successfully tested real urine samples for accuracy.
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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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Article Synopsis
  • The study focused on using carbon black, graphene oxide, copper nanoparticles, and PEDOT:PSS as electrode materials for detecting multiple substances simultaneously, including isoproterenol and caffeine.
  • The surface of the electrodes was thoroughly characterized using techniques like SEM and EDS, revealing fast electron transfer and a large electroactive area.
  • Square-wave voltammetry was used to successfully identify and quantify these compounds in urine and serum, demonstrating the sensor's effectiveness with high recovery rates close to 100%.
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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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Article Synopsis
  • Advances in clinical diagnosis are being enhanced through the use of graphene, a 2D material known for its high surface area and excellent electrical conductivity.
  • The paper provides an overview of how graphene can be incorporated with biological elements like antibodies and DNA probes to create immunosensors and genosensors for improved medical applications.
  • Key topics include various electroanalytical methods for biosensing, the potential for cancer biomarker monitoring, and the development of real-time, point-of-care diagnostic devices using graphene technology.
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