1,721,327 research outputs found
Novel paper-based electroanalytical tools for food surveillance
No full textAnalytical strategies to ensure the quality and safety of food products without the need for skilled personnel are highly required. The simplicity of glucose strips for diabetes monitoring should be translated to the agri-food sector, ensuring easy evaluation of certain molecules and/or the freshness of a beverage/foodstuff. In addition to the well-known advantages that are characteristic of electroanalytical methods over other methods, paper-based materials are being used to further reduce the gap between complex laboratory testing and simple point-of-need testing. This article highlights some of the most recent advances in the development of paper-based electrochemical approaches for food surveillance, specifically focusing on the use of novel paper-based materials. Two examples are discussed: the development of a miniaturized biosensor realized on copy paper for the quantification of ethanol in commercial beers, and the measurement of ascorbic acid in food supplements within printed electronics supports. Paper-based materials have the potential to lower economic costs, simplify the operative tasks, and most importantly reduce waste generation. The continued combination of manufacturing methods and functional (smart) materials will facilitate the implementation of food analysis at the point of need
Polymeric Materials for Printed-Based Electroanalytical (Bio)Applications
No full textAdvances in design of selective interfaces and printed technology have mighty contributed to the expansion of the electroanalysis fame. The real advantage in electroanalytical field is the possibility to manufacture and customize plenty of different sensing platforms, thus avoiding expensive equipment, hiring skilled personnel, and expending economic effort. Growing developments in polymer science have led to further improvements in electroanalytical methods such as sensitivity, selectivity, reproducibility, and accuracy. This review provides an overview of the technical procedures that are used in order to establish polymer effectiveness in printed-based electroanalytical methods. Particular emphasis is placed on the development of electronalytical sensors and biosensors, which highlights the diverse role of the polymeric materials depending on their specific application. A wide overview is provided, taking into account the most significant findings that have been reported from 2010 to 2017
Ultrastructure of human parathyroid cells in health and disease
No full textParathyroid glands (n = 271) removed from 130 patients were examined by light and electron microscopy. A standardized method of tissue processing was employed and morphometry was performed. The aim of the paper is to provide a description of the human parathyroid chief cell ultrastructure in health and disease, with quantitative evaluation of structures involved in secretion of parathyroid hormone in a large case series, and to discuss their role in current diagnostic histopathology. The patients were euparathyroid (n = 10), or affected by primary (n = 97), secondary (n = 8), or tertiary (n = 15) hyperparathyroidism. In normal glands, solid parenchyma was composed of chief cells, large clear cells, transitional-oxyphil cells, and oxyphil cells. Chief cell hyperplasia, pseudo-adenomatous hyperplasia, adenoma, water-clear cell hyperplasia, and carcinoma were the most usual forms of parathyroid disease responsible for primary hyperparathyroidism. In chief cell hyperplasia, all the parathyroid glands were enlarged and the chief cells were in an active state of hormone secretion, with a large Golgi complex, abundant rough endoplasmic reticulum (RER), small lipid droplets, and tortuous plasma membrane. In pseudo-adenomatous hyperplasia, one gland was enlarged and the others displayed a normal size; however, electron microscopic examination and morphometric analysis showed that all the glands had active cells. Adenomas displayed a pattern similar to those of pseudo-adenomatous hyperplasia, with one gland enlarged and the others of normal size. However, ultrastructural examination and morphometry showed that the normal-size glands were hypo-active. Water-clear cell hyperplasia showed cells filled with cytoplasmic vacuoles. In these cells, structures with intermediate features between secretory granules and vacuoles were visible. Nucleo-cytoplasmic atypias were frequently visible in parathyroid carcinoma cells. In secondary and tertiary hyperplasia, active chief cells were regularly mixed with oxyphil or transitional-oxyphil cells. The tertiary hyperplasia was characterized by RER-associated structures that were not found in the normal or other pathological conditions. These results demonstrate that electron microscopy and morphometry represent useful tools in parathyroid histopathology
Non-invasive electrochemistry-driven metals tracing in human biofluids
No full textWearable analytical devices represent the future for fast, de-centralized, and human-centered health monitoring. Electrochemistry-based platforms have been highlighted as the role model for future developments amid diverse strategies and transduction technologies. Among the various relevant analytes to be real-time and non-invasively monitored in bodily fluids, we review the latest wearable achievements towards determining essential and toxic metals. On-skin measurements represent an excellent possibility for humankind: real-time monitoring, digital/fast communication with specialists, quick interventions, removing barriers in developing countries. In this review, we discuss the achievements over the last 5 years in non-invasive electrochemical platforms, providing a comprehensive table for quick visualizing the diverse sensing/technological advances. In the final section, challenges and future perspectives about wearables are deeply discussed
How Can Chemometrics Support the Development of Point of Need Devices?
Full text linkThe necessity to establish novel solutions for decentralized monitoring is attracting attention in all fields of analytical chemistry, i.e., clinical, pharmaceutical, environmental, agri-food. The research around the terms "point-of-need", "point-of-care", "lab-on-chip", "biosensor", "microfluidics", etc. is/has been always aimed at the possibility to produce easy-to-use and fast-response devices to be used by nonspecialists. However, the routes to produce the optimal device might be time-consuming and costly. In this Feature, we would like to highlight the role of chemometric-based approaches that are useful in the conceptualization, production, and data analysis in developing reliable portable devices and also decrease the amount of experiments (thus, costs) at the same time. Readers will be provided a concise overview regarding the most employed chemometric tools used for target identification, design of experiments, data analysis, and digitalization of results applied to the development of diverse portable analytical platforms. This Feature provides a tutorial perspective regarding all the major methods and applications that have been currently developed. In particular, the presence of a concise and informative table assists analytical chemists in utilizing the right chemometrics-based tool depending on the architectures and transduction
Ultrastructural immunolocalization of leptin receptor in neurons of mouse hypothalamic paraventricular nucleus.
No full text3D Paper-Based Origami Device for Programmable Multifold Analyte Preconcentration
Full text linkIn analytical chemistry, preconcentration represents a critical step able to enhance the accuracy of detection; however, the experimental procedures needed to preconcentrate samples might be characterized by drawbacks regarding the whole analytical process, e.g., being complex, invasive, and/or time-consuming. In this study, a novel 3D paper-based origami device is introduced for multifold analyte preconcentration. Leveraging the benefits of paper-based substrates, the proposed architecture boosts sample preconcentration while minimizing time and tasks for measurements, solely by exploiting the porous and versatile nature of paper-based substrates. In comparison with other paper-based approaches reported in the literature for preconcentration, the present architecture offers the ability to be programmed for obtaining the needed sensitivity increase without sacrificing measurement time. To demonstrate the efficacy of the novel approach, the 3D paper-based origami device was deeply characterized, including the most relevant parameters, i.e., disk size and number, unfolding time, and volume, and subsequently applied for the preconcentration and the detection of various analytes in real matrices, namely, mercury in tap water and glucose in sweat, resulting in a 400% and 300% sensitivity enhancement, respectively. This innovative preconcentration tool addresses the limitations of existing conventional methods, providing increased sensitivity without the use of expensive and time-consuming procedures through only exploiting the intrinsic properties of paper-based substrates and a rationale design. The proposed architecture emerges as a universal tool to be adopted and programmed for various analytical systems and fields of application
Paper-Based Materials for Diagnostics
Full text linkNowadays point-of care (POC) devices dominate the field of bioanalysis as they play a pivotal role in improving different aspects of diagnostics including screening, early diagnosis, and disease monitoring. These devices comply with the World Health Organization ASSURED criteria that describe the ideal POC tool. While conventional materials like polymers, silicon, metallic foils, and glass have been exploited in POC device manufacturing, recent innovations relying on paper-based materials have introduced a new era of versatile diagnostic tools. Because of their properties, cellulose and its derivatives have emerged as the most common paper-based substrate in device fabrication. The present review explores recent developments in paper-based diagnostics, covering a wide range of applications including reagent storage and isolation/extraction of the analyte and also serving as a sensing platform. The versatility of paper substrates in various diagnostic devices such as lateral flow assays, electrochemical sensors, microfluidics, etc. is discussed, highlighting their advantages, challenges, and limitations on the context of precision medicine
IBAT nerves in foetal, neonatal and adult rats under different thermogenic conditions: an immunohistochemical study.
No full textElectrochemical biosensors for tracing cyanotoxins in food and environmental matrices
Full text linkThe adoption of electrochemical principles to realize on-field analytical tools for detecting pollutants represents a great possibility for food safety and environmental applications. With respect to the existing transduction mechanisms, i.e., colorimetric, fluorescence, piezoelectric etc., electrochemical mechanisms offer the tremendous advantage of being easily miniaturized, connected with low cost (commercially available) readers and unaffected by the color/turbidity of real matrices. In particular, their versatility represents a powerful approach for detecting traces of emerging pollutants such as cyanotoxins. The combination of electrochemical platforms with nanomaterials, synthetic receptors and microfabrication makes electroanalysis a strong starting point towards decentralized monitoring of toxins in diverse matrices. This review gives an overview of the electrochemical biosensors that have been developed to detect four common cyanotoxins, namely microcystin-LR, anatoxin-a, saxitoxin and cylindrospermopsin. The manuscript provides the readers a quick guide to understand the main electrochemical platforms that have been realized so far, and the presence of a comprehensive table provides a perspective at a glance
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