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BACKGROUND: Cutaneous melanoma (CM) is associated with a higher mortality rate than most other skin cancers. The purpose of this expert consensus panel was to review the published literature on new technological advancements for the diagnosis and prognosis for CM and provide updated guidance on their usage. METHODS: A comprehensive literature search of PubMed, Scopus, and Google Scholar was completed for English-language original research articles on the topics of non-invasive diagnostic and prognostic testing for CM, including gene expression profiling (GEP) and electrical impedance spectroscopy (EIS). A panel of 10 dermatologists with significant expertise in the treatment of CM gathered to review the articles and create consensus statements. A modified Delphi process was used to approve each statement and a strength of recommendation was assigned using widely recognized Strength of Recommendation Taxonomy criteria. RESULTS: The literature search produced 200 articles that met the criteria. A screening of the studies resulted in 19 articles. These were distributed to all panelists for review prior to a roundtable discussion. The panel unanimously voted to adopt 7 consensus statements and recommendations, 5 of which were given a strength of "A", 1 of which was given a strength of "B," and 1 of which was given a strength of "C". CONCLUSION: The 2-GEP test and EIS can aid in the precise diagnosis of clinically indeterminate lesions and the 23-GEP test can be used when histopathology is equivocal. The 31-GEP test can enhance prognostic assessment beyond AJCC8 staging and improve clinical decision-making. J Drugs Dermatol. 2024;23(9):774-781. doi:10.36849/JDD.8365R1.
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Consenso , Espectroscopía Dieléctrica , Melanoma , Neoplasias Cutáneas , Humanos , Melanoma/diagnóstico , Melanoma/genética , Melanoma/patología , Neoplasias Cutáneas/diagnóstico , Neoplasias Cutáneas/patología , Neoplasias Cutáneas/genética , Pronóstico , Espectroscopía Dieléctrica/métodos , Perfilación de la Expresión Génica , Técnica DelphiRESUMEN
Catheter-based embolization has become a widely adopted minimally-invasive treatment for a broad range of applications. However, assessment of embolization endpoints requires x-ray fluoroscopic monitoring, exposing patients and physicians performing embolization procedures to harmful ionizing radiation. Moreover, x-ray fluoroscopy assessment of embolization endpoints is low sensitivity, subjective, and may not reflect the actual physiology of blood flow reduction, thus providing little oversight of the embolization procedure. Inspired by the observation that the dielectric properties of blood differ from those of fluids injected during the embolization procedure, a customized angiographic catheter was created with embedded electrodes for catheter-based electrochemical impedance spectroscopy as a way to monitor embolization. Real-time electrochemical impedance spectroscopy was performed in a phantom and compared to visual and videographic monitoring. Electrochemical impedance spectroscopy was able to sense endpoints of embolization, including stasis, reflux, and persistent flow. This new technique offers a label-free method of sensing embolization progress with potentially higher sensitivity and reproducibility compared to x-ray, as well as offer substantial reduction in x-ray exposure to patients and physicians.
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Catéteres , Espectroscopía Dieléctrica , Embolización Terapéutica , Espectroscopía Dieléctrica/métodos , Humanos , Embolización Terapéutica/métodos , Fantasmas de Imagen , ElectrodosRESUMEN
One of the most promising approaches to food quality assessments is the use of impedance spectroscopy combined with machine learning. Thereby, feature selection is decisive for a high classification accuracy. Physically based features have particularly significant advantages because they are able to consider prior knowledge and to concentrate the data into pertinent understandable information, building a solid basis for classification. In this study, we aim to identify physically based measurable features for muscle type and freshness classifications of bovine meat based on impedance spectroscopy measurements. We carry out a combined study where features are ranked based on their F1-score, cumulative feature selection, and t-distributed Stochastic Neighbor Embedding (t-SNE). In terms of features, we analyze the characteristic points (CPs) of the impedance spectrum and the model parameters (MPs) obtained by fitting a physical model to the measurements. The results show that either MPs or CPs alone are sufficient for detecting muscle type. Combining capacitance (C) and extracellular resistance (Rex) or the modulus of the characteristic point Z1 and the phase at the characteristic frequency of the beta dispersion (Phi2) leads to accurate separation. In contrast, the detection of freshness is more challenging. It requires more distinct features. We achieved a 90% freshness separation using the MPs describing intracellular resistance (Rin) and capacitance (C). A 95.5% freshness separation was achieved by considering the phase at the end of the beta dispersion (Phi3) and Rin. Including additional features related to muscle type improves the separability of samples; ultimately, a 99.6% separation can be achieved by selecting the appropriate features.
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Espectroscopía Dieléctrica , Espectroscopía Dieléctrica/métodos , Animales , Bovinos , Carne/análisis , Aprendizaje Automático , Impedancia Eléctrica , AlgoritmosRESUMEN
Several medical techniques are based on the application of electromagnetic fields (EMFs) on the human body with therapeutic and/or diagnostic aims. The response of human tissues to the applied EMF is mediated by the tissues' dielectric properties, which must therefore be characterized at the frequencies of the considered technique. Due to the heterogeneity and complexity of biological tissues, it is necessary to know their properties in vivo for the specific condition of interest. Traditional techniques for the dielectric characterization of biological tissues are invasive and, as such, not adoptable for this aim. Accordingly, alternative sensors and/or sensing methods are needed. Recently, a new wideband spectroscopy technique was proposed, based on quantities derived from the Magnetic Resonance (MRI) signal. Among these quantities, the water content was proposed to evaluate the dielectric properties at frequencies around a few GHz. This work verifies the possibility of deriving tissues' dielectric properties in the frequency range of 1-20 GHz based on knowledge of the water content. The water content was retrieved through a dehydration procedure for five different ex vivo tissues. The achieved results were compared with references from the literature.
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Agua , Animales , Agua/química , Campos Electromagnéticos , Imagen por Resonancia Magnética/métodos , Impedancia Eléctrica , Humanos , Espectroscopía Dieléctrica/métodosRESUMEN
The moisture content of pharmaceutical powders can significantly impact the physical and chemical properties of drug formulations, solubility, flowability, and stability. However, current technologies for measuring moisture content in pharmaceutical materials require extensive calibration processes, leading to poor consistency and a lack of speed. To address this challenge, this study explores the feasibility of using impedance spectroscopy to enable accurate, rapid testing of moisture content of pharmaceutical materials with minimal to zero calibration. By utilizing electrochemical impedance spectroscopy (EIS) signals, we identify a strong correlation between the electrical properties of the materials and varying moisture contents in pharmaceutical samples. Equivalent circuit modeling is employed to unravel the underlying mechanism, providing valuable insights into the sensitivity of impedance spectroscopy to moisture content variations. Furthermore, the study incorporates deep learning techniques utilizing a 1D convolutional neural network (1DCNN) model to effectively process the complex spectroscopy data. The proposed model achieved a notable predictive accuracy with an average error of just 0.69% in moisture content estimation. This method serves as a pioneering study in using deep learning to provide a reliable solution for real-time moisture content monitoring, with potential applications extending from pharmaceuticals to the food, energy, environmental, and healthcare sectors.
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Aprendizaje Profundo , Espectroscopía Dieléctrica , Espectroscopía Dieléctrica/métodos , Preparaciones Farmacéuticas/análisis , Preparaciones Farmacéuticas/química , Agua/química , CalibraciónRESUMEN
This manuscript describes a novel methodology for studying relaxation dynamics in tissues and cells using characteristic frequency of bioimpedance spectroscopy measurements. The Bioimpedance Formalism allows for the simultaneous study of bioelectrical parameters in the frequency and time domains, providing insight into possible relaxation processes occurring in the tissue or cell of interest. Results from the Cole-Cole analysis showed no multiple relaxation processes associated with heterogeneity, with a visible age group separation in males compared with females. The study of the relaxation dynamic in the time domain revealed that the ß parameter can be used to analyse the charge carriers in tissues, cells, or cancer cells, potentially leading to new diagnostic and therapeutic approaches for cancer and other diseases. Overall, this approach presents a promising area of research for gaining insights into the electrical properties of tissues and cells using bioimpedance methods.
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Espectroscopía Dieléctrica , Impedancia Eléctrica , Humanos , Masculino , Femenino , Adulto , Espectroscopía Dieléctrica/métodos , Persona de Mediana Edad , Adulto Joven , Anciano , Adolescente , Estado de Salud , Niño , PreescolarRESUMEN
Objective.Producing realistic numerical models of neurostimulation electrodes in contact with the electrolyte and tissue, for use in time-domain finite element method simulations while maintaining a reasonable computational burden remains a challenge. We aim to provide a straightforward experimental-theoretical hybrid approach for common electrode materials (Ti, TiN, ITO, Au, Pt, IrOx) that are relevant to the research field of bioelectronics, along with all the information necessary to replicate our approach in arbitrary geometry for real-life experimental applications.Approach.We used electrochemical impedance spectroscopy (EIS) to extract the electrode parameters in the AC regime under different DC biases. The pulsed electrode response was obtained by fast amperometry (FA) to optimize and verify the previously obtained electrode parameters in a COMSOL Multiphysics model. For optimization of the electrode parameters a constant phase element (CPE) needed to be implemented in time-domain.Main results.We find that the parameters obtained by EIS can be used to accurately simulate pulsed response only close to the electrode open circuit potential, while at other potentials we give corrections to the obtained parameters, based on FA measurements. We also find that for many electrodes (Au, TiN, Pt, and IrOx), it is important to implement a distributed CPE rather than an ideal capacitor for estimating the electrode double-layer capacitance. We outline and provide examples for the novel time-domain implementation of the CPE for finite element method simulations in COMSOL Multiphysics.Significance.An overview of electrode parameters for some common electrode materials can be a valuable and useful tool in numerical bioelectronics models. A provided FEM implementation model can be readily adapted to arbitrary electrode geometries and used for various applications. Finally, the presented methodology for parametrization of electrode materials can be used for any materials of interest which were not covered by this work.
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Electrodos , Análisis de Elementos Finitos , Humanos , Simulación por Computador , Espectroscopía Dieléctrica/métodos , Impedancia EléctricaRESUMEN
This article reports on a bioanalytical sensor device that hosts three different transducer principles: impedance spectroscopy, quartz-crystal microbalance with dissipation monitoring, and the thermal-current-based heat-transfer method. These principles utilize a single chip, allowing one to perform either microbalance and heat transfer measurements in parallel or heat transfer and impedance measurements. When taking specific precautions, the three measurement modalities can even be used truly simultaneously. The probed parameters are distinctly different, so that one may speak about multiparametric or "orthogonal" sensing without crosstalk between the sensing circuits. Hence, this sensor allows one to identify which of these label-free sensing principles performs best for a given bioanalytical application in terms of a high signal amplitude and signal-to-noise ratio. As a proof-of-concept, the three-parameter sensor was validated by studying the spontaneous, collective detachment of eukaryotic cells in the presence of a temperature gradient between the QCM chip and the supernatant liquid. In addition to heat transfer, detachment can also be monitored by the impedance- and QCM-related signals. These features allow for the distinguishing between different yeast strains that differ in their flocculation genes, and the sensor device enables proliferation monitoring of yeast colonies over time.
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Técnicas Biosensibles , Tecnicas de Microbalanza del Cristal de Cuarzo , Técnicas Biosensibles/métodos , Técnicas Biosensibles/instrumentación , Tecnicas de Microbalanza del Cristal de Cuarzo/métodos , Temperatura , Espectroscopía Dieléctrica/métodos , Diseño de Equipo , Saccharomyces cerevisiae , Adhesión CelularRESUMEN
Detecting chronic autoimmune disorders (ADs) early reduces the risk of morbidity, disability, and mortality and offers the possibility of significant therapeutic action in a timely manner. Developing low-cost, reliable, and sensitive sensors for ADs can ensure the efficient utilization of healthcare resources at earlier stages. Here, we report on the development of an electrochemical biosensor for sensing CXCL10, a chemokine protein that serves as a biomarker for autoimmune diseases. A self-assembly strategy is used for the immobilization of biorecognition elements on a plastic chip electrode (PCE). A homemade PCE offers a versatile and cost-effective scaffold for sensing applications. Gold nanoparticles were electrochemically deposited on the electrode via the reduction of gold ions on the PCE galvanostatically. The CXCL10 antibody and recognition elements were immobilized on the gold-deposited PCE. The attachment of recognition molecules was confirmed by energy-dispersive scanning electron microscopy, atomic force microscopy, infrared spectroscopy, and electrochemical techniques. Electrochemical impedance spectroscopy (EIS) was used for the detection of CXCL10 within a concentration range spanning from pico- to micro-molar levels. The sensor exhibited remarkable linearity in both buffer and plasma solutions, with a limit of detection (LOD) of up to 0.72 pg mL-1.
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Enfermedades Autoinmunes , Técnicas Biosensibles , Quimiocina CXCL10 , Técnicas Electroquímicas , Electrodos , Oro , Nanopartículas del Metal , Técnicas Biosensibles/métodos , Técnicas Biosensibles/instrumentación , Humanos , Enfermedades Autoinmunes/diagnóstico , Enfermedades Autoinmunes/sangre , Enfermedades Autoinmunes/inmunología , Oro/química , Nanopartículas del Metal/química , Quimiocina CXCL10/análisis , Quimiocina CXCL10/sangre , Quimiocina CXCL10/inmunología , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Diagnóstico Precoz , Plásticos/química , Espectroscopía Dieléctrica/métodos , Límite de Detección , Anticuerpos Inmovilizados/inmunología , Anticuerpos Inmovilizados/químicaRESUMEN
Muscle dysfunction and muscle atrophy are common complications resulting from Chronic Obstructive Pulmonary Disease (COPD). The evaluation of the peripheral muscles can be carried out through the assessment of their structural components from ultrasound images or their functional components through isometric and isotonic strength tests. This evaluation, performed mainly on the quadriceps muscle, is not only of great interest for diagnosis, prognosis and monitoring of COPD, but also for the evaluation of the benefits of therapeutic interventions. In this work, bioimpedance spectroscopy technology is proposed as a low-cost and easy-to-use alternative for the evaluation of peripheral muscles, becoming a feasible alternative to ultrasound images and strength tests for their application in routine clinical practice. For this purpose, a laboratory prototype of a bioimpedance device has been adapted to perform segmental measurements in the quadriceps region. The validation results obtained in a pseudo-randomized study in patients with COPD in a controlled clinical environment which involved 33 volunteers confirm the correlation and correspondence of the bioimpedance parameters with respect to the structural and functional parameters of the quadriceps muscle, making it possible to propose a set of prediction equations. The main contribution of this manuscript is the discovery of a linear relationship between quadriceps muscle properties and the bioimpedance Cole model parameters, reaching a correlation of 0.69 and an average error of less than 0.2 cm regarding the thickness of the quadriceps estimations from ultrasound images, and a correlation of 0.77 and an average error of 3.9 kg regarding the isometric strength of the quadriceps muscle.
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Impedancia Eléctrica , Enfermedad Pulmonar Obstructiva Crónica , Humanos , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico por imagen , Masculino , Músculo Cuádriceps/fisiopatología , Músculo Cuádriceps/diagnóstico por imagen , Músculo Cuádriceps/fisiología , Persona de Mediana Edad , Anciano , Femenino , Espectroscopía Dieléctrica/métodos , Espectroscopía Dieléctrica/instrumentación , Fuerza Muscular/fisiología , Músculo Esquelético/fisiopatología , Músculo Esquelético/diagnóstico por imagenRESUMEN
The traditional methods in early caries detection had many limitations. So, this study aimed to evaluate the clinical performance of alternating current impedance spectroscopy ACIST in comparison with digital radiograph and ICDAS-II in detection of occlusal carious lesions. Occlusal surfaces of molar and premolar teeth from 40 adult participants were examined by two observers using three diagnostic methods: (1) international caries detection and assessment system (ICDAS-II) (2) digital radiograph (DR) and (3) Cariescan Pro device (ACIST). Agreement analysis and the difference in sensitivities and specificities were evaluated. The results showed an excellent agreement in the different groups. The difference from the visual tactile against ACIST scoring for enamel caries detection, was statistically significant (p = 0.012) and the agreement was moderate (k = 0.509). For dentinal caries the difference was not statistically significant (p > 0.05) and the agreement was similarly moderate (k < 0.6). The difference from the digital radiograph against ACIST scoring, for enamel caries, digital radiography had significantly higher sensitivity and specificity than ACIST (p < 0.001) while for dentinal caries detection and overall, ACIST had higher sensitivity and digital radiography had higher specificity and the difference was statistically significant (p < 0.001). Visual-tactile examination is a considered as feasible and valid technique for occlusal caries detection, digital radiography is superior to ACIST in diagnosing enamel caries, but it could underestimate the caries depth, ACIST is a reliable tool for detecting occlusal caries in dentin.
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Caries Dental , Espectroscopía Dieléctrica , Radiografía Dental Digital , Humanos , Caries Dental/diagnóstico por imagen , Caries Dental/diagnóstico , Adulto , Masculino , Femenino , Radiografía Dental Digital/métodos , Estudios Prospectivos , Espectroscopía Dieléctrica/métodos , Sensibilidad y Especificidad , Reproducibilidad de los Resultados , Adulto Joven , Esmalte Dental/diagnóstico por imagen , Esmalte Dental/patología , Persona de Mediana EdadRESUMEN
Bioimpedance spectrum (BIS) measurements have a great future in in vitro experiments, meeting all the requirements for non-destructive and label-free methods. Nevertheless, a real basic research can provide the necessary milestones to achieve the success of the method. In this paper a self-developed technology-based approach for in vitro assays is proposed. Authors invented a special graphene-based measuring plate in order to assess the high sensitivity and reproducibility of introduced technique. The design of the self-produced BIS plates maximizes the detection capacity of qualitative changes in cell culture and it is robust against physical effects and artifacts. The plates do not influence the viability and proliferation, however the results are robust, stable and reproducible regardless of when and where the experiments are carried out. In this study, physiological saline concentrations, two cancer and stem cell lines were utilized. All the results were statistically tested and confirmed. The findings of the assays show, that the introduced BIS technology is appropriate to be used in vitro experiments with high efficacy. The experimental results demonstrate high correlation values across the replicates, and the model parameters suggested that the characteristic differences among the various cell lines can be detected using appropriate hypothesis tests.
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Impedancia Eléctrica , Humanos , Reproducibilidad de los Resultados , Grafito/química , Línea Celular Tumoral , Supervivencia Celular , Espectroscopía Dieléctrica/métodos , Proliferación CelularRESUMEN
Bioimpedance is a diagnostic sensing method used in medical applications, ranging from body composition assessment to detecting skin cancer. Commonly, discrete-component (and at times integrated) circuit variants of the Howland Current Source (HCS) topology are employed for injection of an AC current. Ideally, its amplitude should remain within 1% of its nominal value across a frequency range, and that nominal value should be programmable. However, the method's applicability and accuracy are hindered due to the current amplitude diminishing at frequencies above 100 kHz, with very few designs accomplishing 1 MHz, and only at a single nominal amplitude. This paper presents the design and implementation of an adaptive current source for bioimpedance applications employing automatic gain control (AGC). The "Adaptive Howland Current Source" (AHCS) was experimentally tested, and the results indicate that the design can achieve less than 1% amplitude error for both 1 mA and 100 µA currents for bandwidths up to 3 MHz. Simulations also indicate that the system can be designed to achieve up to 19% noise reduction relative to the most common HCS design. AHCS addresses the need for high bandwidth AC current sources in bioimpedance spectroscopy, offering automatic output current compensation without constant recalibration. The novel structure of AHCS proves crucial in applications requiring higher ß-dispersion frequencies exceeding 1 MHz, where greater penetration depths and better cell status assessment can be achieved, e.g., in the detection of skin or breast cancer.
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Impedancia Eléctrica , Humanos , Espectroscopía Dieléctrica/métodos , Composición Corporal/fisiologíaRESUMEN
Plant stress diagnosis is essential for efficient crop management and productivity increase. Under stress, plants undergo physiological and compositional changes. Vegetation indices obtained from leaf reflectance spectra and bioimpedance spectroscopy provide information about the external and internal aspects of plant responses, respectively. In this study, bioimpedance and vegetation indices were noninvasively acquired from sweet basil (Ocimum basilicum L.) leaves exposed to three types of stress (drought, salinity, and chilling). Integrating the vegetation index, a novel approach, contains information about the surface of plants and bioimpedance data, which indicates the internal changes of plants. The fusion of these two datasets was examined to classify the types and severity of stress. Among the eight supervised machine learning models (three linear and five non-linear), the support vector machine (SVM) exhibited the highest accuracy in classifying stress types. Bioimpedance spectroscopy alone exhibited an accuracy of 0.86 and improved to 0.90 when fused with vegetation indices. Additionally, for drought and salinity stresses, it was possible to classify the early stage of stress with accuracies of 0.95 and 0.93, respectively. This study will allow us to classify the different types and severity of plant stress, prescribe appropriate treatment methods for efficient cost and time management of crop production, and potentially apply them to low-cost field measurement systems.
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Técnicas Biosensibles , Aprendizaje Automático , Ocimum basilicum , Hojas de la Planta , Estrés Fisiológico , Ocimum basilicum/química , Hojas de la Planta/química , Técnicas Biosensibles/métodos , Espectroscopía Dieléctrica/métodos , Espectroscopía Infrarroja Corta/métodos , Sequías , Máquina de Vectores de Soporte , SalinidadRESUMEN
Measurement of endothelial and epithelial barrier integrity is important for a variety of in vitro models, including Transwell assays, cocultures, and organ-on-chip platforms. Barrier resistance is typically measured by trans-endothelial electrical resistance (TEER), but TEER is invasive and cannot accurately measure isolated monolayer resistance in coculture or most organ-on-chip devices. These limitations are addressed by porous membrane electrical cell-substrate impedance sensing (PM-ECIS), which measures barrier integrity in cell monolayers grown directly on permeable membranes patterned with electrodes. Here, we advanced the design and utility of PM-ECIS by investigating its sensitivity to working electrode size and correlation with TEER. Gold electrodes were fabricated on porous membrane inserts using hot embossing and UV lithography, with working electrode diameters of 250, 500, and 750 µm within the same insert. Sensitivity to resistance changes (4 kHz) during endothelial barrier formation was inversely proportional to electrode size, with the smallest being the most sensitive (p < 0.001). Similarly, smaller electrodes were most sensitive to changes in impedance (40 kHz) corresponding to cell spreading and proliferation (p < 0.001). Barrier disruption with both EGTA and thrombin was detectable by all electrode sizes. Resistances measured by PM-ECIS vs TEER for sodium chloride solutions were positively and significantly correlated for all electrode sizes (r > 0.9; p < 0.0001), but only with 750 µm electrodes for endothelial monolayers (r = 0.71; p = 0.058). These data inform the design and selection of PM-ECIS electrodes for specific applications and support PM-ECIS as a promising alternative to conventional TEER for direct, noninvasive, real-time assessment of cells cultured on porous membranes in conventional and organ-on-chip barrier models.
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Espectroscopía Dieléctrica , Impedancia Eléctrica , Humanos , Porosidad , Espectroscopía Dieléctrica/métodos , Espectroscopía Dieléctrica/instrumentación , Células Endoteliales de la Vena Umbilical Humana , Electrodos , Células Endoteliales/citología , Células Endoteliales/fisiología , Membranas ArtificialesRESUMEN
BACKGROUND: Accurate volume status assessment and dry weight achievement are the most challenging goals for a nephrologist. We aimed to evaluate the role of ultrasonographic parameters including lung ultrasound and inferior vena cava (IVC) measurements as practical methods of volume status assessment in children on hemodialysis by comparing them with established techniques, such as clinical evaluation and bioimpedance spectroscopy. METHODS: A prospective cross-sectional study compared pre- and post-dialysis volume status using bioimpedance spectroscopy (BIS) parameters and clinical data with ultrasonographic lung B-lines and IVC parameters in children on regular hemodialysis. RESULTS: A total 60 children (mean age 9.4 ± 2.8 years) were enrolled. Twenty patients (33.3%) were clinically overloaded to varying degrees (17 patients had mild to moderate signs of fluid overload and 3 patients had moderate to severe signs of fluid overload). All other patients (66.7%) were clinically euvolemic. Sonographic parameters were significantly lower post-dialysis than pre-dialysis, including lung B-line count and IVC diameter. IVC collapsibility index mean was significantly higher post-dialysis than pre-dialysis. There was a significant correlation between the lung B-line count, IVC parameters, and BIS-measured overhydration both before and after hemodialysis. Nine patients had ≥ 8 B-lines post-dialysis, only three of them were hypertensive. CONCLUSIONS: Clinical criteria alone are not specific for determining accurate fluid status in pediatric hemodialysis patients. Lung B-line score, IVC parameters, and BIS may be complementary to each other and to clinical data. Lung B-lines outperform IVC measurements and BIS in subclinical volume overload detection in pediatric hemodialysis patients.
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Pulmón , Diálisis Renal , Ultrasonografía , Vena Cava Inferior , Humanos , Diálisis Renal/efectos adversos , Niño , Masculino , Femenino , Estudios Transversales , Estudios Prospectivos , Vena Cava Inferior/diagnóstico por imagen , Adolescente , Pulmón/diagnóstico por imagen , Pulmón/patología , Preescolar , Espectroscopía Dieléctrica/métodos , Desequilibrio Hidroelectrolítico/etiología , Desequilibrio Hidroelectrolítico/diagnóstico , Volumen SanguíneoRESUMEN
This paper reports a rapid and sensitive sensor for the detection and quantification of the COVID-19 N-protein (N-PROT) via an electrochemical mechanism. Single-frequency electrochemical impedance spectroscopy was used as a transduction method for real-time measurement of the N-PROT in an immunosensor system based on gold-conjugate-modified carbon screen-printed electrodes (Cov-Ag-SPE). The system presents high selectivity attained through an optimal stimulation signal composed of a 0.0 V DC potential and 10 mV RMS-1 AC signal at 100 Hz over 300 s. The Cov-Ag-SPE showed a log response toward N-PROT detection at concentrations from 1.0 ng mL-1 to 10.0 µg mL-1, with a 0.977 correlation coefficient for the phase (θ) variation. An ML-based approach could be created using some aspects observed from the positive and negative samples; hence, it was possible to classify 252 samples, reaching 83.0, 96.2 and 91.3% sensitivity, specificity, and accuracy, respectively, with confidence intervals (CI) ranging from 73.0 to 100.0%. Because impedance spectroscopy measurements can be performed with low-cost portable instruments, the immunosensor proposed here can be applied in point-of-care diagnostics for mass testing, even in places with limited resources, as an alternative to the common diagnostics methods.
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Técnicas Biosensibles , COVID-19 , Espectroscopía Dieléctrica , Oro , SARS-CoV-2 , COVID-19/diagnóstico , COVID-19/virología , Técnicas Biosensibles/métodos , Técnicas Biosensibles/instrumentación , Humanos , SARS-CoV-2/aislamiento & purificación , SARS-CoV-2/inmunología , Espectroscopía Dieléctrica/instrumentación , Espectroscopía Dieléctrica/métodos , Oro/química , Electrodos , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Inmunoensayo/métodos , Inmunoensayo/instrumentación , Proteínas de la Nucleocápside de Coronavirus/inmunología , Proteínas de la Nucleocápside de Coronavirus/análisis , Carbono/química , Fosfoproteínas/análisisRESUMEN
Hepatocellular carcinoma (HCC) stands as the most prevalent form of primary liver cancer, predominantly affecting patients with chronic liver diseases such as hepatitis B or C-induced cirrhosis. Diagnosis typically involves blood tests (assessing liver functions and HCC biomarkers), imaging procedures such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), and liver biopsies requiring the removal of liver tissue for laboratory analysis. However, these diagnostic methods either entail lengthy lab processes, require expensive imaging equipment, or involve invasive techniques like liver biopsies. Hence, there exists a crucial need for rapid, cost-effective, and noninvasive techniques to characterize HCC, whether in serum or tissue samples. In this study, we developed a spiral sensor implemented on a printed circuit board (PCB) technology that utilizes impedance spectroscopy and applied it to 24 tissues and sera samples as proof of concept. This newly devised circuit has successfully characterized HCC and normal tissue and serum samples. Utilizing the distinct dielectric properties between HCC cells and serum samples versus the normal samples across a specific frequency range, the differentiation between normal and HCC samples is achieved. Moreover, the sensor effectively characterizes two HCC grades and distinguishes cirrhotic/non-cirrhotic samples from tissue specimens. In addition, the sensor distinguishes cirrhotic/non-cirrhotic samples from serum specimens. This pioneering study introduces Electrical Impedance Spectroscopy (EIS) spiral sensor for diagnosing HCC and liver cirrhosis in clinical serum-an innovative, low-cost, rapid (< 2 min), and precise PCB-based technology without elaborate sample preparation, offering a novel non-labeled screening approach for disease staging and liver conditions.
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Carcinoma Hepatocelular , Espectroscopía Dieléctrica , Neoplasias Hepáticas , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/sangre , Carcinoma Hepatocelular/patología , Humanos , Espectroscopía Dieléctrica/métodos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/sangre , Neoplasias Hepáticas/patología , Hígado/patología , Biomarcadores de Tumor/sangreRESUMEN
Modern medicine has increased the human lifespan. However, with an increase in average lifespan risk of amyloidosis increases. Amyloidosis is a condition characterized by protein misfolding and aggregation. Early detection of amyloidosis is crucial, yet conventional diagnostic methods are costly and lack precision, necessitating innovative tools. This review explores recent advancements in diverse amyloid detection methodologies, highlighting the need for interdisciplinary research to develop a miniaturized electrochemical biosensor leveraging nanotechnology. However, the diagnostics industry faces obstacles such as skilled labor shortages, standardized selection processes, and concurrent multi-analyte identification challenges. Research efforts are focused on integrating electrochemical techniques into clinical applications and diagnostics, with the successful transition of miniaturized technologies from development to testing posing a significant hurdle. Label-free transduction techniques like voltammetry and electrochemical impedance spectroscopy (EIS) have gained traction due to their rapid, cost-effective, and user-friendly nature.
Asunto(s)
Amiloide , Técnicas Biosensibles , Técnicas Biosensibles/métodos , Humanos , Amiloide/metabolismo , Amiloide/análisis , Amiloide/química , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Amiloidosis/diagnóstico , Amiloidosis/metabolismo , Espectroscopía Dieléctrica/métodosRESUMEN
This study presented a new method to design a MIP-based electrochemical sensor that could improve the selective and sensitive detection of ipratropium bromide (IPR). The polymeric film was designed using 2-hydroxyethyl methacrylate (HEMA) as the basic monomer, 2-hydroxy-2-methylpropiophenone as the initiator, ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent, and N-methacryloyl-L-aspartic acid (MAAsp) as the functional monomer. The presence of MAAsp results in the functional groups in imprinting binding sites, while the presence of poly(vinyl alcohol) (PVA) allows the generation of porous materials not only for sensitive sensing but also for avoiding electron transport limitations. Electrochemical characterizations of the changes at each stage of the MIP preparation process were confirmed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). In addition, morphological characterizations of the developed sensor were performed using scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and contact angle measurements. Theoretical calculations were also performed to explain/confirm the experimental results better. It was found that the results of the calculations using the DFT approach agreed with the experimental data. The MAAsp-IPR@MIP/GCE sensor was developed using the photopolymerization method, and the sensor surface was obtained by exposure to UV lamp radiation at 365â¯nm. The improved MIP-based electrochemical sensor demonstrated the ability to measure IPR for standard solutions in the linear operating range of 1.0 × 10-12-1.0 × 10-11 M under optimized conditions. For standard solutions, the limit of detection (LOD) and limit of quantification (LOQ) were obtained as 2.78 × 10-13 and 9.27 × 10-13 M, respectively. The IPR recovery values for the inhalation form were calculated as 101.70â¯% and 100.34â¯%, and the mean relative standard deviations (RSD) were less than 0.76â¯% in both cases. In addition, the proposed modified sensor demonstrated remarkable sensitivity and selectivity for rapid assessment of IPR in inhalation forms. The sensor's unique selectivity is demonstrated by its successful performance even in the presence of IPR impurities.