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1.
FASEB J ; 38(10): e23700, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38787606

RESUMEN

Distinguishing quiescent from rupture-prone atherosclerotic lesions has significant translational and clinical implications. Electrochemical impedance spectroscopy (EIS) characterizes biological tissues by assessing impedance and phase delay responses to alternating current at multiple frequencies. We evaluated invasive 6-point stretchable EIS sensors over a spectrum of experimental atherosclerosis and compared results with intravascular ultrasound (IVUS), molecular positron emission tomography (PET) imaging, and histology. Male New Zealand White rabbits (n = 16) were placed on a high-fat diet, with or without endothelial denudation via balloon injury of the infrarenal abdominal aorta. Rabbits underwent in vivo micro-PET imaging of the abdominal aorta with 68Ga-DOTATATE, 18F-NaF, and 18F-FDG, followed by invasive interrogation via IVUS and EIS. Background signal-corrected values of impedance and phase delay were determined. Abdominal aortic samples were collected for histology. Analyses were performed blindly. EIS impedance was associated with markers of plaque activity including macrophage infiltration (r = .813, p = .008) and macrophage/smooth muscle cell (SMC) ratio (r = .813, p = .026). Moreover, EIS phase delay correlated with anatomic markers of plaque burden, namely intima/media ratio (r = .883, p = .004) and %stenosis (r = .901, p = .002), similar to IVUS. 68Ga-DOTATATE correlated with intimal macrophage infiltration (r = .861, p = .003) and macrophage/SMC ratio (r = .831, p = .021), 18F-NaF with SMC infiltration (r = -.842, p = .018), and 18F-FDG correlated with macrophage/SMC ratio (r = .787, p = .036). EIS with phase delay integrates key atherosclerosis features that otherwise require multiple complementary invasive and non-invasive imaging approaches to capture. These findings indicate the potential of invasive EIS to comprehensively evaluate human coronary artery disease.


Asunto(s)
Aterosclerosis , Espectroscopía Dieléctrica , Animales , Conejos , Espectroscopía Dieléctrica/métodos , Masculino , Aterosclerosis/patología , Aterosclerosis/diagnóstico por imagen , Aorta Abdominal/patología , Aorta Abdominal/diagnóstico por imagen , Placa Aterosclerótica/diagnóstico por imagen , Placa Aterosclerótica/patología , Tomografía de Emisión de Positrones/métodos , Fenotipo , Modelos Animales de Enfermedad , Macrófagos/patología , Macrófagos/metabolismo
2.
FASEB J ; 38(18): e70069, 2024 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-39315853

RESUMEN

Coronary plaque rupture remains the prominent mechanism of myocardial infarction. Accurate identification of rupture-prone plaque may improve clinical management. This study assessed the discriminatory performance of electrochemical impedance spectroscopy (EIS) in human cardiac explants to detect high-risk atherosclerotic features that portend rupture risk. In this single-center, prospective study, n = 26 cardiac explants were collected for EIS interrogation of the three major coronary arteries. Vessels in which advancement of the EIS catheter without iatrogenic plaque disruption was rendered impossible were not assessed. N = 61 vessels underwent EIS measurement and histological analyses. Plaques were dichotomized according to previously established high rupture-risk parameter thresholds. Diagnostic performance was determined via receiver operating characteristic areas-under-the-curve (AUC). Necrotic cores were identified in n = 19 vessels (median area 1.53 mm2) with a median fibrous cap thickness of 62 µm. Impedance was significantly greater in plaques with necrotic core area ≥1.75 mm2 versus <1.75 mm2 (19.8 ± 4.4 kΩ vs. 7.2 ± 1.0 kΩ, p = .019), fibrous cap thickness ≤65 µm versus >65 µm (19.1 ± 3.5 kΩ vs. 6.5 ± 0.9 kΩ, p = .004), and ≥20 macrophages per 0.3 mm-diameter high-power field (HPF) versus <20 macrophages per HPF (19.8 ± 4.1 kΩ vs. 10.2 ± 0.9 kΩ, p = .002). Impedance identified necrotic core area ≥1.75 mm2, fibrous cap thickness ≤65 µm, and ≥20 macrophages per HPF with AUCs of 0.889 (95% CI: 0.716-1.000) (p = .013), 0.852 (0.646-1.000) (p = .025), and 0.835 (0.577-1.000) (p = .028), respectively. Further, phase delay discriminated severe stenosis (≥70%) with an AUC of 0.767 (0.573-0.962) (p = .035). EIS discriminates high-risk atherosclerotic features that portend plaque rupture in human coronary artery disease and may serve as a complementary modality for angiography-guided atherosclerosis evaluation.


Asunto(s)
Enfermedad de la Arteria Coronaria , Vasos Coronarios , Espectroscopía Dieléctrica , Placa Aterosclerótica , Humanos , Enfermedad de la Arteria Coronaria/patología , Espectroscopía Dieléctrica/métodos , Masculino , Femenino , Placa Aterosclerótica/patología , Placa Aterosclerótica/diagnóstico por imagen , Persona de Mediana Edad , Estudios Prospectivos , Anciano , Vasos Coronarios/patología , Aterosclerosis/patología , Factores de Riesgo
3.
Nano Lett ; 24(30): 9283-9288, 2024 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-39023006

RESUMEN

The electrostatic environment around nanoscale molecular junctions modulates charge transport; solvents alter this environment. Methods to directly probe solvent effects require correlating measurements of the local electrostatic environment with charge transport across the metal-molecule-metal junction. Here, we measure the conductance and current-voltage characteristics of molecular wires using a scanning tunneling microscope-break junction (STM-BJ) setup in two commonly used solvents. Our results show that the solvent environment induces shifts in molecular conductance, which we quantify, but more importantly we find that the solvent also impacts the magnitude of current rectification in molecular junctions. By incorporating electrochemical impedance spectroscopy into the STM-BJ setup, we measure the capacitance of the dipole layer formed at the metal-solvent interface and show that rectification can be correlated with solvent capacitance. These results provide a method of quantifying the impact of the solvent environment and a path toward improved environmental control of molecular devices.

4.
Nano Lett ; 24(30): 9147-9154, 2024 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-39028759

RESUMEN

Photoenhanced batteries, where light improves the electrochemical performance of batteries, have gained much interest. Recent reports suggest that light-to-heat conversion can also play an important role. In this work, we study Prussian blue analogues (PBAs), which are known to have a high photothermal heating efficiency and can be used as cathodes for Li-ion batteries. PBAs were synthesized directly on a carbon collector electrode and tested under different thermally controlled conditions to show the effect of photothermal heating on battery performance. Our PBA electrodes reach temperatures that are 14% higher than reference electrodes using a blue LED, and a capacity enhancement of 38% was achieved at a current density of 1600 mA g-1. Additionally, these batteries show excellent cycling stability with a capacity retention of 96.6% in dark conditions and 94.8% in light over 100 cycles. Overall, this work shows new insights into the effects leading to improved battery performance in photobatteries.

5.
J Comput Chem ; 45(16): 1380-1389, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38407482

RESUMEN

Electrical equivalent circuits are a widely applied tool with which electrical processes can be rationalized. There is a wide-ranging selection of fields from bioelectrochemistry to batteries to fuel cells making use of this tool. Enabling meta-analysis on the similarities and differences in the used circuits will help to identify commonly used circuits and aid in evaluating the underlying physics. We present a method and an implementation that enables the conversion of circuits included in scientific publications into a machine-readable form for generating machine learning datasets or circuit simulations.

6.
Chemistry ; 30(3): e202302968, 2024 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-37870886

RESUMEN

In the last two decades, perchlorate salts have been identified as environmental pollutants and recognized as potential substances affecting human health. We describe self-assembled monolayers (SAMs) of novel semiaza-bambus[6]urils (semiaza-BUs) equipped with thioethers or disulfide (dithiolane) functionalities as surface-anchoring groups on gold electrodes. Cyclic voltammetry (CV) with Fe(CN)6 3-/4- as a redox probe, together with X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and ellipsometry, were employed to characterize the interactions at the interface between the anchoring groups and the metal substrate. Data showed that the anion receptors' packing on the gold strongly depends on the anchoring group. As a result, SAMs of BUs with lipoic amide side chains show a concentration-dependent layer thickness. The BU SAMs are extremely stable on repeated electrochemical potential scans and can selectively recognize perchlorate anions. Our electrochemical impedance spectroscopy (EIS) studies indicated that semiaza-BU equipped with the lipoic amide side chains binds perchlorate (2-100 mM) preferentially over other anions such as F- , Cl- , I- , AcO- , H2 PO4 - , HPO4 2- , SO4 2- , NO2 - , NO3 - , or CO3 2- . The resistance performance is 10 to 100 times more efficient than SAMs containing all other tested anions.

7.
Anal Biochem ; 687: 115451, 2024 04.
Artículo en Inglés | MEDLINE | ID: mdl-38154624

RESUMEN

Herein this study, a facile, efficient and disposable electrochemical sensor has been prepared by electropolymerization of glycine (poly(GLY)) on the surface of pencil graphite electrode (PGE). The surface topology of the equipped poly(GLY) modified pencil graphite electrode (poly(GLY)/PGE) and bare pencil graphite electrode (BPGE) has been characterized by the scanning electron microscopy (SEM) combined with energy dispersive x-ray analysis (EDX) and charge transfer behaviour was measured by electron impedance spectroscopy (EIS) method. The voltammetric behaviour of anticancer, 5-fluorouracil (5-FU) in the presence of theophylline (THP) has been carried out in 0.1 M phosphate buffer solution (PBS) of physiological pH 7.0 using different techniques such as cyclic voltammetry (CV), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV). The proposed poly(GLY)/PGE shows augmented peak current for 5-FU at lower potential side over the BPGE due to the electrocatalytic behaviour of modifier layers wrapped on the electrode surface. The kinetic behaviour of 5-FU at modified electrode surface was studied by varying different parameters such as pH, scan rate and concentration study in 0.1 M PBS used as a supporting electrolyte. The limit of detection (LOD) for 5-FU was attained using DPV method with different concentrations (1.0-13.0 µM) and it was found to be 0.012 µM. The possible electrochemical reaction of 5-FU was proposed and it was incorporated by two electrons and two protons mechanism at modified electrode surface. The voltammetric response of poly(GLY)/PGE towards the determination of 5-FU was unaffected in the presence of some excipients in addition to the remarkable stability and reproducibility. The applicability of the proposed sensor has been performed by real sample investigation of 5-FU with a substantial percentage of recovery results in all optimized conditions.


Asunto(s)
Antineoplásicos , Grafito , Grafito/química , Fluorouracilo , Teofilina , Reproducibilidad de los Resultados , Técnicas Electroquímicas/métodos , Electrodos , Glicina
8.
Anal Biochem ; 688: 115472, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38266666

RESUMEN

Due to the late detection of stomach cancer, this cancer usually causes high mortality. The development of an electrochemical genosensor to measure microRNA 106b (miR-106b), as a gastric cancer biomarker, is the aim of this effort. In this regard, first, 1,3,5-benzenetricarboxylate (BTC) metal-organic frameworks (Zn-BTC MOF) were self-assembled on the glassy carbon electrode and then the probe (ssDNA) was immobilized on it. The morphology Zn-BTC MOF was characterized by SEM, FT-IR, Raman and X-Ray techniques. Zn-BTC MOF as a biosensor substrate has strong interaction with ssDNA. Quantitative measurement of miR-106b was performed by electrochemical impedance spectroscopy (EIS). To perform this measurement, the difference of the charge transfer resistances (ΔRct) of Nyquist plots of the ssDNA probe modified electrode before and after hybridization with miR-106b was obtained and used as an analytical signal. Using the suggested genosensor, it is possible to measure miR-106b in the concentration range of 1.0 fM to 1.0 µM with a detection limit of 0.65 fM under optimal conditions. Moreover, at the genosensor surface, miR-106b can be detected from a non-complementary and a single base mismatch sequence. Also, the genosensor was used to assess miR-106b in a human serum sample and obtained satisfactory results.


Asunto(s)
Técnicas Biosensibles , MicroARNs , Neoplasias Gástricas , Humanos , Biomarcadores de Tumor/genética , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/genética , Espectroscopía Infrarroja por Transformada de Fourier , Técnicas Biosensibles/métodos , ADN de Cadena Simple/genética , MicroARNs/genética , Zinc , Técnicas Electroquímicas/métodos , Límite de Detección
9.
Anal Biochem ; 689: 115504, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38458306

RESUMEN

SARS-CoV-2 emerged in late 2019 and quickly spread globally, resulting in significant morbidity, mortality, and socio-economic disruptions. As of now, collaborative global efforts in vaccination and the advent of novel diagnostic tools have considerably curbed the spread and impact of the virus in many regions. Despite this progress, the demand remains for low-cost, accurate, rapid and scalable diagnostic tools to reduce the influence of SARS-CoV-2. Herein, the angiotensin-converting enzyme 2 (ACE2), a receptor for SARS-CoV-2, was immobilized on two types of electrodes, a screen-printed gold electrode (SPGE) and a screen-printed carbon electrode (SPCE), to develop electrochemical biosensors for detecting SARS-CoV-2 with high sensitivity and selectivity. This was achieved by using 1H, 1H, 2H, 2H-perfluorodecanethiol (PFDT) and aryl diazonium salt serving as linkers for SPGEs and SPCEs, respectively. Once SARS-CoV-2 was anchored onto the ACE2, the interaction of the virus with the redox probe was analyzed using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Aryl diazonium salt was observed as a superior linker compared to PFDT due to its consistent performance in the modification of the SPCEs and effective ACE2 enzyme immobilization. A distinct pair of redox peaks in the cyclic voltammogram of the biosensor modified with aryl diazonium salt highlighted the redox reaction between the functional groups of SARS-CoV-2 and the redox probe. The sensor presented a linear relationship between the redox response and the logarithm of SARS-CoV-2 concentration, with a detection limit of 1.02 × 106 TCID50/mL (50% tissue culture infectious dose). Furthermore, the biosensor showed remarkable selectivity towards SARS-CoV-2 over H1N1virus.


Asunto(s)
Enzima Convertidora de Angiotensina 2 , Técnicas Biosensibles , COVID-19 , SARS-CoV-2 , Humanos , Técnicas Biosensibles/métodos , COVID-19/diagnóstico , Técnicas Electroquímicas , Electrodos , Oro/química , SARS-CoV-2/aislamiento & purificación
10.
Chemphyschem ; : e202400528, 2024 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-38945822

RESUMEN

Electrochemical impedance spectroscopy (EIS), a conventional and alternating-current-(AC)-based technique for impedance measurement, is commonly used in battery diagnosis. However, it requires expensive equipment and demanding operating conditions and is complex and model-dependent in data analysis. Recently, novel direct current (DC) analytics have emerged as an alternative to EIS. They are simple yet powerful, being capable of revealing impedance information that traditionally could only be obtained through EIS and determining Li-ion diffusion coefficient. Besides, a complete EIS spectrum can be predicted based on constant current charging curves in the support of machine learning methods. This work highlights the similarities and discrepancies between DC techniques and EIS in the electrochemical analysis of Li-ion batteries. Looking ahead, DC techniques may be a promising substitute for EIS in future battery diagnosis, requiring simplified equipment while offering a deep understanding of battery impedance and its underlying electrochemical processes.

11.
Chem Rec ; 24(5): e202400007, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38621230

RESUMEN

Energy harvesting and energy storage are two critical aspects of supporting the energy transition and sustainability. Many studies have been conducted to achieve excellent performance devices for these two purposes. As energy-storing devices, supercapacitors (SCs) have tremendous potential to be applied in several sectors. Some electrochemical characterizations define the performance of SCs. Electrochemical impedance spectroscopy (EIS) is one of the most powerful analyses to determine the performance of SCs. Some parameters obtained from this analysis include bulk resistance, charge-transfer resistance, total resistance, specific capacitance, response frequency, and response time. This work provides a holistic and comprehensive review of utilizing EIS for SC characterization. Overall, researchers can benefit from this review by gaining a comprehensive understanding of the utilization of electrochemical impedance spectroscopy (EIS) for characterizing supercapacitors (SCs), enabling them to enhance SC performance and contribute to the advancement of energy harvesting and storage technologies.

12.
Environ Sci Technol ; 58(41): 18404-18413, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-39360939

RESUMEN

Water treatment membranes play crucial roles in applications such as desalination, wastewater treatment, and potable water reuse. In a prior study, we introduced a novel method, combining electrical impedance spectroscopy with dynamic mechanical analysis, to quantify single-layer homogeneous membrane compaction up to 12.5 psi. Now we extend the method's capabilities to quantify real-time compaction of multilayer heterogeneous nanofiltration and reverse osmosis (RO) membranes up to 330 psi. Our findings demonstrate that membrane compaction does not solely occur in the support/backing layer. The air pockets between the polysulfone support and the polyester backing layers, which were not discussed previously, account for up to 18% and 14% of total membrane compaction for the nanofiltration and RO membranes. For the nanofiltration membrane, the majority of compaction (up to 45%) occurs in the void spaces of the backing layer, while for the RO membrane, the majority of compaction (up to 40%) occurs in the solid material of the backing layer. We also confirm, with experimental results, the importance of using compressive testing instead of tensile testing to accurately characterize compaction. Membrane fatigue is characterized by experimental trends including: increasing irrevocable compaction, increasing creep/instantaneous compaction ratios, and increasing strains in hysteresis experiments.


Asunto(s)
Membranas Artificiales , Presión , Purificación del Agua , Purificación del Agua/métodos , Filtración , Ósmosis
13.
Anal Bioanal Chem ; 416(8): 1983-1995, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38358533

RESUMEN

Phytotoxins produced by marine microalgae, such as paralytic shellfish toxins (PSTs), can accumulate in bivalve molluscs, representing a human health concern due to the life-threatening symptoms they cause. To avoid the commercialization of contaminated bivalves, monitoring programs were established in the EU. The purpose of this work is the implementation of a PST transforming enzyme-carbamoylase-in an impedimetric test for rapid simultaneous detection of several carbamate and N-sulfocarbamoyl PSTs. Carbamoylase hydrolyses carbamate and sulfocarbamoyl toxins, which may account for up to 90% of bivalve toxicity related to PSTs. Conformational changes of carbamoylase accompanying enzymatic reactions were probed by Fourier transform mid-infrared spectroscopy (FT-MIR) and electrochemical impedance spectroscopy (EIS). Furthermore, a combination of EIS with a metal electrode and a carbamoylase-based assay was employed to harness changes in the enzyme conformation and adsorption on the electrode surface during the enzymatic reaction as an analytical signal. After optimization of the working conditions, the developed impedimetric e-tongue could quantify N-sulfocarbamoyl toxins with a detection limit of 0.1 µM. The developed e-tongue allows the detection of these toxins at concentration levels observed in bivalves with PST toxicity close to the regulatory limit. The quantification of a sum of N-sulfocarbamoyl PSTs in naturally contaminated mussel extracts using the developed impedimetric e-tongue has been demonstrated.


Asunto(s)
Bivalvos , Intoxicación por Mariscos , Animales , Humanos , Toxinas Marinas/química , Nariz Electrónica , Bivalvos/química , Mariscos/análisis , Carbamatos , Intoxicación por Mariscos/etiología
14.
Electrochim Acta ; 4882024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38654828

RESUMEN

Electrochemical impedance spectroscopy (EIS) is a powerful technique for studying the interaction at electrode/solution interfaces. The adoption of EIS for obtaining analytical signals in biosensors based on aptamers is gaining popularity because of its advantageous characteristics for molecular recognition. Neuropeptide Y (NPY), the most abundant neuropeptide in the body, plays a crucial role with its stress-relieving properties. Quantitative measurement of NPY is imperative for understanding its role in these and other biological processes. Although aptamer-modified electrodes for NPY detection using EIS present a promising alternative, the correlation between the data obtained and the adsorption process on the electrodes is not fully understood. Various studies utilize the change in charge transfer resistance when employing an active redox label. In contrast, label-free measurement relies on changes in capacitance. To address these challenges, we focused on the interaction between aptamer-modified planar electrodes and their target, NPY. We proposed utilizing -ω*Zimag as the analytical signal, which facilitated the analysis of the adsorption process using an analogous Langmuir isotherm equation. This approach differs from implantable microelectrodes, which adhere to the Freundlich adsorption isotherm. Notably, our method obviates the need for a redox label and enables the detection of NPY at concentrations as low as 20 pg/mL. This methodology demonstrated exceptional selectivity, exhibiting a signal difference of over 20-to-1 against potential interfering molecules.

15.
Mikrochim Acta ; 191(2): 94, 2024 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-38217713

RESUMEN

Based on the electrochemical impedance method, a marker-free biosensor with aptamer as a biometric element was developed for the determination of doxorubicin (DOX). By combining aptamer with rigid tetrahedral DNA nanostructures (TDNs) and fixing them on the surface of gold electrode (GE) as biometric elements, the density and directivity of surface nanoprobes improved, and DOX was captured with high sensitivity and specificity. DOX was captured by immobilized aptamers on the GE, which inhibited electron transfer between the GE and [Fe(CN)6]3-/4- in solution, resulting in a change in electrochemical impedance. When the DOX concentration was between 10.0 and 100.0 nM, the aptasensor showed a linear relationship with charge transfer resistance, the relative standard deviation (RSD) ranged from 3.6 to 5.9%, and the detection limit (LOD) was 3.0 nM. This technique offered a successful performance for the determination of the target analyte in serum samples with recovery in the range 97.0 to 99.6% and RSD ranged from 4.8 to 6.5%. This method displayed the advantages of fast response speed, good selectivity, and simple sensor structure and showed potential application in therapeutic drug monitoring.


Asunto(s)
Aptámeros de Nucleótidos , Nanoestructuras , Aptámeros de Nucleótidos/química , Impedancia Eléctrica , ADN , Oro/química , Doxorrubicina
16.
Mikrochim Acta ; 191(3): 146, 2024 02 19.
Artículo en Inglés | MEDLINE | ID: mdl-38372811

RESUMEN

Salmonella contamination is a major global health challenge, causing significant foodborne illness. However, current detection methods face limitations in sensitivity and time, which mostly rely on the culture-based detection techniques. Hence, there is an immediate and critical need to enhance early detection, reduce the incidence and impact of Salmonella contamination resulting in outbreaks. In this work, we demonstrate a portable non-faradaic, electrochemical sensing platform capable of detecting Salmonella in potable water with an assay turnaround time of ~ 9 min. We evaluated the effectiveness of this sensing platform by studying two sensor configurations: one utilizing pure gold (Au) and the other incorporating a semiconductor namely a zinc oxide thin film coated on the surface of the gold (Au/ZnO). The inclusion of zinc oxide was intended to enhance the sensing capabilities of the system. Through comprehensive experimentation and analysis, the LoD (limit of detection) values for the Au sensor and Au/ZnO sensor were 0.9 and 0.6 CFU/mL, respectively. In addition to sensitivity, we examined the sensing platform's precision and reproducibility. Both the Au sensor and Au/ZnO sensor exhibited remarkable consistency, with inter-study percentage coefficient of variation (%CV) and intra-study %CV consistently below 10%. The proposed sensing platform exhibits high sensitivity in detecting low concentrations of Salmonella in potable water. Its successful development demonstrates its potential as a rapid and on-site detection tool, offering portability and ease of use. This research opens new avenues for electrochemical-based sensors in food safety and public health, mitigating Salmonella outbreaks and improving water quality monitoring.


Asunto(s)
Agua Potable , Óxido de Zinc , Reproducibilidad de los Resultados , Oro , Salmonella
17.
Mikrochim Acta ; 191(2): 115, 2024 01 30.
Artículo en Inglés | MEDLINE | ID: mdl-38286844

RESUMEN

Luteinizing hormone (LH) is a useful biomarker for identifying ovulation events in the cows to predict the time of ovulation to achieve a high success rate of conception following artificial insemination. Although antibody-based radioimmunoassay and enzyme-linked immunosorbent assay are being used for LH measurement, these techniques are expensive, time-consuming, and require expertise and sophisticated laboratory facilities. So, there is a need for a field-applicable, affordable, easy-to-use method for LH detection. For developing such a specific, quantitative, and inexpensive system, an aptamer-based smartphone-enabled aptasensor has been investigated. The aptamer was used instead of the antibody as a biorecognition element due to its comparative stability at ambient temperature, ease of synthesis, and cost-effectiveness. Electrochemical impedance spectroscopy has been used to obtain label-free detection of LH within 20 min in ~ 20 µL sample volume. The screen-printed gold electrode is compatible with a smartphone-enabled miniaturized device (Sensit Smart; Palmsens BV, The Netherlands) and was fabricated with the aptamer to detect LH in biological fluids (limit of detection 0.80 and 0.61 ng/mL in buffer and undiluted/unprocessed serum, respectively, with the dynamic range of detection of 0.01 to 50 ng/mL). All the data were obtained in the 10 kHz to 0.10 Hz frequency range at a bias potential of 0.30 V with an alternating potential of 10 mV. The clinical relevance of the sensor was evaluated in 10 serum samples collected from dairy animals which established a high correlation with standard LH-ELISA (κ > 0.87). The aptasensor can be stored at room temperature for 30 days without any significant loss in electrochemical sensing ability.


Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Animales , Bovinos , Hormona Luteinizante , Sistemas de Atención de Punto , Aptámeros de Nucleótidos/química , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos
18.
Mikrochim Acta ; 191(7): 380, 2024 06 10.
Artículo en Inglés | MEDLINE | ID: mdl-38858258

RESUMEN

A sensing interface co-constructed from the two-dimensional conductive material (Ag@MXene) and an antifouling cyclic multifunctional peptide (CP) is described. While the large surface area of Ag@MXene loads more CP probes, CP binds to Ag@MXene to form a fouling barrier and ensure the structural rigidity of the targeting sequence. This strategy synergistically enhances the biosensor's sensitivity and resistance to contamination. The SPR results showed that the binding affinity of the CP to the target was 6.23 times higher than that of the antifouling straight-chain multifunctional peptide (SP) to the target. In the 10 mg/mL BSA electrochemical fouling test, the fouling resistance of Ag@MXene + CP (composite sensing interface of CP combined with Ag@MXene) was 30 times higher than that of the bare electrode. The designed electrochemical sensor exhibited good selectivity and wide dynamic response range at PD-L1 concentrations from 0.1 to 50 ng/mL. The lowest detection limit was 24.54 pg/mL (S/N = 3). Antifouling 2D materials with a substantial specific surface area, coupled with non-straight chain antifouling multifunctional peptides, offer a wide scope for investigating the sensitivity and antifouling properties of electrochemical sensors.


Asunto(s)
Técnicas Biosensibles , Técnicas Electroquímicas , Límite de Detección , Péptidos Cíclicos , Plata , Plata/química , Técnicas Electroquímicas/métodos , Péptidos Cíclicos/química , Péptidos Cíclicos/sangre , Técnicas Biosensibles/métodos , Humanos , Incrustaciones Biológicas/prevención & control , Electrodos
19.
Mikrochim Acta ; 191(10): 617, 2024 09 24.
Artículo en Inglés | MEDLINE | ID: mdl-39316098

RESUMEN

A new, sensitive, and cost-effective lab-on-paper-based immunosensor was designed based on electrochemical impedance spectroscopy (EIS) for the detection of exosomes. EIS was selected as the determination method since there was a surface blockage in electron transfer by binding the exosomes to the transducer. Briefly, the carbon working electrode (WE) on the paper electrode (PE) was modified with gold particles (AuPs@PE) and then conjugated with anti-CD9 (Anti-CD9/AuPs@PE) for the detection of exosomes. Variables involved in the biosensor design were optimized with the univariate mode. The developed method presents the limit of detection of  8.7 × 102 exosomes mL-1, which is lower than that of many other available methods under the best conditions. The biosensor was also tested with urine samples from cancer patients with high recoveries. Due to this  a unique, low-cost, biodegradable technology is presented that can directly measure exosomes without labeling them for early cancer or metastasis detection.


Asunto(s)
Técnicas Biosensibles , Espectroscopía Dieléctrica , Exosomas , Oro , Límite de Detección , Papel , Espectroscopía Dieléctrica/métodos , Técnicas Biosensibles/métodos , Exosomas/química , Humanos , Oro/química , Electrodos , Anticuerpos Inmovilizados/inmunología , Tetraspanina 29/análisis , Tetraspanina 29/orina , Nanopartículas del Metal/química , Inmunoensayo/métodos
20.
Mikrochim Acta ; 191(11): 712, 2024 10 29.
Artículo en Inglés | MEDLINE | ID: mdl-39470822

RESUMEN

A new type of label-free electrochemical immunosensor for the high-sensitivity determination of parathion was developed based on the oriented immobilization of nanobody (VHH9) on a gold nanoparticle-loaded polyvinyl alcohol/citric acid nanofiber membrane-modified electrode. The morphology characterization and assembly process of the modified materials were investigated using scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Under the optimum conditions, the label-free electrochemical immunosensor for parathion exhibited a linear range of 0.0015-6400 ng/mL and a low detection limit of 0.48 pg/mL, the signal response of which was 10 times higher than that of the randomly immobilized VHH9. The immunosensor possessed high selectivity, good repeatability and reusability (keeping above 90% of its initial activity after repeating 8 times), and stability (remaining 90% after 9 weeks of storage). Finally, the average recoveries of parathion from food samples were 93.76-105.73% with the coefficient of variation being 2.65-6.85%, showing good correlation with UPLC (R2 = 0.9950). Therefore, our nanobody immobilization protocol is simple and effective and proves the potential to be utilized as a promising candidate for sensing platform.


Asunto(s)
Técnicas Biosensibles , Técnicas Electroquímicas , Oro , Límite de Detección , Nanofibras , Nanofibras/química , Oro/química , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Anticuerpos de Dominio Único/inmunología , Anticuerpos de Dominio Único/química , Nanopartículas del Metal/química , Inmunoensayo/métodos , Anticuerpos Inmovilizados/inmunología , Electrodos , Alcohol Polivinílico/química , Contaminación de Alimentos/análisis , Membranas Artificiales
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