ABSTRACT
Ferritin is a major intracellular iron storage protein present in all cells, tissues and tissue fluids of the organism. Low ferritin levels result in lower iron concentrations which is directly involved with anemia. Elevated levels of ferritin, or hyperferritinemia, indicate the presence of viruses and bacteria into the body. Clinical observations on COVID-19 patients have reported cases accompanied by elevated levels of ferritin in blood. The aim of this research was to develop a new voltametric immunosensor for determination of ferritin based on the principles of biological recognition, antibody-antigen reaction combined with nanotechnology and the advantages of electrochemical detection strategies. Carbon paste electrode (CPE) modified with grain natural material, characterized as titanium magnetite is used as substrate for immunosensor. The immobilization of ferritine antibody (FeAb) can be effectively improved by using a thin film of surfactant, trimethyl-tetradecylammonium chloride (TTDC), onto the CPE substrate. The modification procedure of the immunosensor is characterized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The effect of FeAb incubation time and the FeAb-ferritine reaction kinetic are explored to provide optimum analytical performance. The quantitative determination of ferritine is based on the change in DPV response before and after antibodyantigen reaction. All measurements are done in pH = 7 phosphate buffer saline (PBS) at room temperature. Calibration method was based on the reduction of the DPV peak (%) in relation to the ferritin concentration. The time required for the immobilization of FeAb was studied, which resulted in 60 minutes, as well as the equilibrium time of the FeAb-ferritin reaction, which resulted in 30 minutes. The linear range resulted within the interval 0.05-0.5 mg/L ferritin (R2 = 0.9947). The recovery of ferritin addition in real sample matrix resulted from 87% to 125%. The specificity of FeAbferritin reaction evaluated in terms of binding constant, resulted in the order of 10-9 L/mol indicating a specific antibody-antigen reaction. Based on the values of affinity constants calculated in each case the quantification of ferritin with the studied sensors is based on the specific antiferritin-ferritin bond. The use of surfactant layer (TTDC), improves the process of antiferritin immobilization, which affects the increase of sensitivity and improve the analytical performance of the imunosensor. © 2023, Consulting and Training Center - KEY. All rights reserved.
ABSTRACT
Two inexpensive and simple methods for synthesis of carbon nanodots were applied and compared to each other, namely a hydrothermal and microwave-assisted method. The synthesized carbon nanodots were characterized using transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis), photoluminescence (PL), Fourier transform-infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The synthesized microwave carbon nanodots had smaller particle size and were thus chosen for better electrochemical performance. Therefore, they were used for our modification process. The proposed electrodes performance characteristics were evaluated according to the IUPAC guidelines, showing linear response in the concentration range 10−6–10−2, 10−7–10−2, and 10−8–10−2 M of tobramycin with a Nernstian slope of 52.60, 58.34, and 57.32 mV/decade for the bare, silver nanoparticle and carbon nanodots modified carbon paste electrodes, respectively. This developed potentiometric method was used for quantification of tobramycin in its co-formulated dosage form and spiked human plasma with good recovery percentages and without interference of the co-formulated drug loteprednol etabonate and excipients.
ABSTRACT
Recent years have been associated with the development of various sensor-based technologies in response to the undeniable need for the rapid and precise analysis of an immense variety of pharmaceuticals. In this regard, special attention has been paid to the design and fabrication of sensing platforms based on electrochemical detection methods as they can offer many advantages, such as portability, ease of use, relatively cheap instruments, and fast response times. Carbon paste electrodes (CPEs) are among the most promising conductive electrodes due to their beneficial properties, including ease of electrode modification, facile surface renewability, low background currents, and the ability to modify with different analytes. However, their widespread use is affected by the lack of sufficient selectivity of CPEs. Molecularly imprinted polymers (MIPs) composed of tailor-made cavities for specific target molecules are appealing complementary additives that can overcome this limitation. Accordingly, adding MIP to the carbon paste matrix can contribute to the required selectivity of sensing platforms. This review aims to present a categorized report on the recent research and the outcomes in the combinatory fields of MIPs and CPEs for determining pharmaceuticals in complex and simple matrices. CPEs modified with MIPs of various pharmaceutical compounds, including analgesic drugs, antibiotics, antivirals, cardiovascular drugs, as well as therapeutic agents affecting the central nervous system (CNS), will be addressed in detail.Copyright © 2023 Elsevier B.V.
ABSTRACT
In this work, a simple, cheap, sensitive, and selective modified carbon paste electrode is proposed for the electroanalytical determination of Levofloxacin (LEVO), the drug used to treat pneumonia caused by coronavirus. The electrochemical polymerization method was applied to create a thin poly-murexide film (POMUR) on the bare carbon paste electrode (BCPE) surface to enhance its electrocatalytic activity. The peak current response of LEVO obtained by POMUR/CPE was increased by 14.2 μA compared to BCPE. Scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques were employed to characterize BCPE and POMUR/CPE. Under the optimal experimental circumstances, the prepared sensor was capable of determining LEVO with a low limit of detection (LOD) of 7.18 nM (S/N = 3) for a linear dynamic range of 25 – 1 × 103 nM utilizing differential pulse voltammetry (DPV). Moreover, the practical applicability of POMUR/CPE for determining LEVO in pharmaceutical formulations and biological samples (human serum) demonstrated high sensitivity and selectivity with a recovery of 95.08 – 100.5 %. © 2023 Wiley-VCH GmbH.
ABSTRACT
Daclatasvir dihydrochloride (DAC) is an anti-hepatitis C virus (HCV) drug that has recently proven to be a promising candidate for the treatment of SARS-CoV-2. Still, there is a lack of sensitive potentiometric methods for its determination. In this work, carbon paste sensors based on dibenzo-18-crown-6 (DB18C6) were fabricated and optimized for the sensitive and selective potentiometric determination of DAC in Daclavirocyrl® tablets, serum, and urine samples. The best performance was obtained by two sensors referred to as sensor I and sensor II. Both sensors exhibited a wide linear response range of 5×10-9 - 1×10-3 mol/L, and Nernstian slopes of 29.8 ± 1.18 and 29.5 ± 1.00 mV/decade, with limits of detection, 4.8×10-9 and 3.2×10-9 mol/L, for the sensors I and II, respectively. Sensors I and II displayed fast response times of 5-8 and 5-6 s, respectively, with great reversibility and no memory effect. Moreover, the sensors exhibited a lifetime of 16 days. For the study of sensors morphology and elucidation of the interaction mechanism, the scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (1H NMR) techniques were performed. A selectivity study was performed, and the proposed sensors exhibited good discrimination between DAC and potentially coexisting interferents with sensor II displaying better selectivity. Finally, sensor II was successfully applied for the determination of DAC in the above-mentioned samples, with recovery values ranging from 99.25 to 101.42%, and relative standard deviation (RSD) values ranging from 0.79 to 1.53% which reflected the high accuracy and precision.
ABSTRACT
To reduce the progression of the viral process in patients infected with COVID-19, new treatments and drug active substances are needed. One of these drugs is Molnupiravir (MNP) which has a direct antiviral effect and has also proven to be highly effective in reducing the azopharyngeal SARS-CoV-2 infectious virus and viral RNA. Due to the importance and frequent use of this drug in the treatment of COVID-19, its accurate, quick, and cheap detection in pharmaceutical or biological samples is crucial. In this work, electrochemical behavior and sensitive voltammetric determination of MNP are described using a magnetite nanoparticle modified carbon paste electrode (Fe3O4@CPE) for the first time. Fe3O4 nanoparticles (NPs) were characterized by recording their transmission electron microscopy (TEM) images, energy dispersive X-ray (EDX), and X-ray diffraction (XRD) spectra. Cyclic voltammetric measurements showed that MNP was irreversibly oxidized at Fe3O4@CPE at 760 mV in pH 2.0 Britton Robinson buffer solution (BRBS). The peak current of MNP was increased approximately threefold at Fe3O4@CPE compared to bare CPE due to a good electrocatalytic efficiency of Fe3O4 NPs. According to differential pulse voltammetric studies, the fabricated electrode exhibited a linear range (LR) between 0.25 and 750 µM with sensitivity and limit of detection (LOD) of 4591.0 µA mM-1 cm-2 and 0.05 µM, respectively. On the other hand, although lower sensitivity (327.3 µA mM-1 cm-2) was obtained from CV compared to DPV, a wider linear calibration curve between 0.25 and 1500 µM was obtained in CV. Studies performed in tablet samples confirmed that the Fe3O4@CPE exhibits high applicability for selective and accurate voltammetric determination of MNP in real samples.
ABSTRACT
Curcumae Longae Rhizoma (CLR) is the rhizome of Curcuma longa L. Pharmacological studies show that CLR can be used to treat cervical cancer, lung cancer, lupus nephritis, and other conditions. In this paper, we review botany, traditional application, phytochemistry, pharmacological activity, and pharmacokinetics of CLR. The literature from 1981 to date was entirely collected from online databases, such as Web of Science, Google Scholar, China Academic Journals full-text database (CNKI), Wiley, Springer, PubMed, and ScienceDirect. The data were also obtained from ancient books, theses and dissertations, and Flora Reipublicae Popularis Sinicae. There are a total of 275 compounds that have been isolated from CLR, including phenolic compounds, volatile oils, and others. The therapeutic effect of turmeric has been expanded from breaking blood and activating qi in the traditional sense to antitumor, anti-inflammatory, antioxidation, neuroprotection, antibacterial, hypolipidemic effects, and other benefits. However, the active ingredients and mechanisms of action related to relieving disease remain ill defined, which requires more in-depth research and verification at a clinical level.
ABSTRACT
Used face masks resulting from the COVID-19 pandemic are forming a new waste stream that poses a considerable environmental risk to the ecosystem if not properly disposed of. This work explored an environmentally friendly solution to diverting such waste to a value-added application, i.e., fabricating waste mask microfibers for use in cementitious composites. To improve the interfacial transition zone between mask fibers and cement paste matrix, the microfibers made from recycled medical masks are pre-treated in an aqueous solution of graphene oxide (GO, at 0.05 wt%). In a cement paste with the water/cement ratio of 0.40, the GO-treated mask fibers admixed at 0.1 vol% showed great potential for improving the splitting tensile strength (by 47% at 28 days), even though they slightly decreased the compressive strength of the paste (by 3% at 28 days). Microscopic investigation was also carried out to reveal the enhancement mechanism of GO-treated fibers. This study preliminarily demonstrated the feasibility to upcycle waste masks in the concrete industry and provided a new strategy for disposing of waste masks.
ABSTRACT
The whole world was virtually not prepared for COVID-19. The medical remedy was understandably unavailable. So, Europeans, Americans, and similar regions of the world fell back on their traditional approaches to disruptive events of the type that COVID-19 represents. Many African countries would be largely led to mechanically copy the template of these other regions to varying degrees irrespective of the often starkly different economic, political, and social milieus that confront them. This article examines the policy response to the COVID-19 pandemic by African political office holders and the politics of COVID-19 remedy in Africa as scenes for the enactment of cultural racism and biomedical imperialism. Relying on the theoretical frameworks of cultural racism and postcolonialism, the article interrogates what happened with Africa’s policy response and attempts to find a home-grown remedy to the global COVID-19 pandemic as reflections of the underlying patterns of relationalities that determine the behavior of those in leadership positions under normal times—a pattern that only appears in stark relief under the shadow of the COVID-19 pandemic. [ FROM AUTHOR] Copyright of Journal of Black Studies is the property of Sage Publications Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)
ABSTRACT
This study developed a nanosensor for the detection and determination of favipiravir, a presumed drug that has potential therapeutic efficacy in treating COVID-19 patients, from tablets and serum samples. This nanosensor was obtained by adding the optimum amount of diamond nanoparticles into carbon paste. For the determination of favipiravir adsorptive stripping differential pulse (AdSDPV) and adsorptive stripping square wave voltammetry (AdSSWV) were used. Limit of detection values were found as 4.83 x 10(-9) M and 2.44 x 10' M for bulk and 5.18 x 10(-8) M and 4.38 x 10(-8) M for serum samples using AdSDPV and AdSSWV, respectively. Recovery studies made of the tablet and serum produced satisfactory results.