RESUMEN
Electrochemical biosensors are known for their high sensitivity, selectivity, and low cost. Recently, they have gained significant attention and became particularly important as promising tools for the detection of COVID-19 biomarkers, since they offer a rapid and accurate means of diagnosis. Biorecognition strategies are a crucial component of electrochemical biosensors and determine their specificity and sensitivity based on the interaction of biological molecules, such as antibodies, enzymes, and DNA, with target analytes (e.g., viral particles, proteins and genetic material) to create a measurable signal. Different biorecognition strategies have been developed to enhance the performance of electrochemical biosensors, including direct, competitive, and sandwich binding, alongside nucleic acid hybridization mechanisms and gene editing systems. In this review article, we present the different strategies used in electrochemical biosensors to target SARS-CoV-2 and other COVID-19 biomarkers, as well as explore the advantages and disadvantages of each strategy and highlight recent progress in this field. Additionally, we discuss the challenges associated with developing electrochemical biosensors for clinical COVID-19 diagnosis and their widespread commercialization.
Asunto(s)
Técnicas Biosensibles , COVID-19 , Humanos , COVID-19/diagnóstico , SARS-CoV-2/genética , Prueba de COVID-19 , Biomarcadores , Técnicas ElectroquímicasRESUMEN
This study aimed to investigate the antioxidant activity of extracts obtained from jabuticaba (Myrciaria cauliflora) seeds. Ethanolic (ETJS), methanolic (MEJS), aqueous (AQJS), and propanone (PRJS) extracts was assessed by measuring spectrophotometrically their ability to scavenge DPPH· , ABTS·+ , HOCl, and O2 ·- radicals. Electrochemical methods were employed, and the obtained data presented a good correlation with the radical scavenging results. The extracts were also able to attenuate lipid peroxidation induced by Fe2+ ions in phospholipids due to their chelation ability. The extracts protected human erythrocytes against oxidative cellular damage caused by AAPH, which was confirmed by using FESEM analysis. PRJS extract demonstrated the highest effect in all assays used in this work. Our findings prove that jabuticaba seeds are an important source of antioxidants which act by different mechanisms. This study opens new frontiers regarding the use of this fruit byproduct as a food additive. PRACTICAL APPLICATIONS: Jabuticaba seeds are usually discarded as waste by food industries, but they are rich in bioactive products and present interesting biological properties. Herein, we demonstrated that their extracts show remarkable antioxidant power against different reactive oxygen species, which are involved in several human pathologies. In this way, this by-product can be further used in the development of products to protect the human body against diseases related to oxidative stress.
Asunto(s)
Antioxidantes , Myrtaceae , Antioxidantes/química , Eritrocitos , Humanos , Myrtaceae/química , Estrés Oxidativo , Extractos Vegetales/química , Semillas/químicaRESUMEN
In the present work, gold nanoparticles were synthesized through a green route by using, for the first time, polysaccharides extracted from pineapple gum (PG) as the reducing and capping agent. The obtained nanoparticles (AuNPs-PG) were characterized by UV-VIS, FTIR, TEM, FESEM, EDX, XRD, and zeta potential measurements, which confirmed that PG was effective to produce AuNPs with an average diameter of 10.3 ± 1.6 nm. The AuNPs-PG were employed as the modifier of glassy carbon paste electrodes (CPE/AuNPs-PG), which were applied as sensitive electrochemical sensors to the determination of the antihistamine drug promethazine hydrochloride (PMZ). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements showed that the AuNPs-PG could enhance the electronic transfer properties of the glassy carbon paste, which was due to their large surface area and high electrical conductivity. After optimization of the instrumental parameters of square wave voltammetry (SWV) through a Box-Behnken factorial design, a linear relationship between the anodic peak current and PMZ concentration was obtained in the range from 2.0 to 15.7 µmol L-1 in McIlvaine buffer solution pH 5.0. The detection and quantification limits were found to be equal to 1.33 and 4.44 µmol L-1, respectively. The developed sensors could successfully quantify PMZ in different commercial pharmaceutical formulations, with satisfactory levels of accuracy and precision. In addition to improving the analytical features of the electrodes, hemocompatibility assays carried out on erythrocytes and leukocytes showed that the AuNPs-PG do not exhibit toxic effects on the referred cells. This interesting behavior enables their use in biocompatible electrochemical sensing platforms as well as for future biomedical investigations.
Asunto(s)
Ananas , Técnicas Biosensibles , Nanopartículas del Metal , Técnicas Electroquímicas , Electrodos , Oro , Límite de Detección , PolisacáridosRESUMEN
In the present work, the green synthesis of silver nanoparticles (AgNPs) using the sulfated polysaccharide porphyran (PFR) as capping agent and d-glucose as reducing agent is described. PFR was extracted from red seaweed and characterized by employing 13C NMR and determination of total sugar, protein, and sulfate contents. The obtained AgNPs-PFR were characterized by using UV-VIS spectroscopy, zeta potential determination, FESEM, and TEM, which demonstrated that PFR was effective at capping the AgNPs, yielding stable suspensions. The AgNPs-PFR presented good antimicrobial properties against Gram-positive and Gram-negative bacterial strains (Staphylococcus aureus and Escherichia coli, respectively). The AgNPs-PFR were also employed as the modifier of carbon paste electrodes, which were efficiently applied as electrochemical sensors for the determination of 5-fluorouracil (5-FU), an important anticancer drug, through square wave voltammetry (SWV). The AgNPs-PFR improved the electrochemical properties of the electrodes, and enhanced their electroanalytical performance. The developed sensing device presented detection and quantification limits equal to 10.7 and 35.8 µmol L-1, respectively, towards 5-FU determination. The proposed electrochemical sensor successfully quantified 5-FU in a real pharmaceutical formulation, confirming its potential as a new promising analytical detection tool for 5-FU quality control purposes.
Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Fluorouracilo/química , Nanopartículas del Metal/química , Sefarosa/análogos & derivados , Plata/química , Electroquímica , Electrodos , Sefarosa/químicaRESUMEN
Apolipoprotein E4 (ApoE4) has a key role on the onset and progression of Alzheimer's disease (AD), since it favours the deposition of toxic amyloid-beta (Aß) aggregates in the brain. These effects might result from the interaction between ApoE4 and specific DNA promoters related to cellular autophagy pathways and to the expression of neuroprotective proteins, like sirtuin-1. Herein, we modified gold electrodes with mixed self-assembled monolayers of 6-mercapto-1-hexanol and thiolated DNA oligonucleotides related to CLEAR (associated with autophagic processes that enable the clearance of toxic species, such as Aß) and SirT1 (related to the expression of sirtuin-1) promoter sequences. The interactions of the immobilized DNA sequences with isoforms of ApoE (ApoE4/ApoE3/ApoE2) were investigated by differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) measurements. By monitoring current and charge transfer resistance (Rct) variations, CLEAR showed to interact specifically with ApoE4, whereas SirT1 showed a higher affinity to ApoE4 compared to ApoE3 and ApoE2. To the best of our knowledge, this is the first report about the application of electrochemical techniques to investigate the sequence-specific interaction between ApoE isoforms and CLEAR and SirT1 oligonucleotides.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Apolipoproteínas E/metabolismo , Sirtuina 1/genética , Enfermedad de Alzheimer/genética , Apolipoproteína E2/metabolismo , Apolipoproteína E3/metabolismo , Apolipoproteína E4/metabolismo , Secuencia de Bases , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Electrodos , Humanos , Ácidos Nucleicos Inmovilizados/genética , Ácidos Nucleicos Inmovilizados/metabolismo , Regiones Promotoras Genéticas , Proteínas Recombinantes/metabolismoRESUMEN
Herein, we report the antioxidant activity of cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) in pure and mixed solutions at different ratios, as well as of six different Cannabis sativa extracts containing various proportions of CBD and THC by using spectrophotometric (reducing power assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), hypochlorous acid (HOCl) scavenging assays) and electrochemical methods (cyclic voltammetry and differential pulse voltammetry). The isolated cannabinoids, the different stoichiometric ratios of CBD and THC, and the natural extracts proved to have remarkable antioxidant properties in all the methods employed in this work. The antioxidant activity of CBD and THC was compared against that of the well-defined antioxidants such as ascorbic acid (AA), resveratrol (Resv) and (-)-epigallocatechin-3-gallate (EGCG). Clear evidence of the synergistic and antagonistic effects between CBD and THC regarding to their antioxidant activities was observed. Moreover, a good correlation was obtained between the optical and electrochemical methods, which proved that the reported experimental procedures can easily be adapted to determine the antioxidant activity of extracts from various Cannabis sativa species and related compounds.
Asunto(s)
Cannabidiol/química , Cannabis/química , Dronabinol/química , Depuradores de Radicales Libres/química , Extractos Vegetales/química , Cannabidiol/análisis , Dronabinol/análisis , Técnicas Electroquímicas/métodos , Depuradores de Radicales Libres/análisis , Extractos Vegetales/análisisRESUMEN
Zika virus (ZIKV) has recently become a global health challenge due to its rapid geographical expansion, since it is associated with serious neurological anomalies such as Guillain-Barré syndrome and microcephaly. Currently, the techniques for ZIKV diagnosis require labor-intensive, expensive and lengthy tests using sophisticated equipment. Moreover, false-positive or false-negative results can occur. In the present work, a DNA biosensor to detect ZIKV in real human serum samples was developed using an oxidized glassy carbon electrode (ox-GCE) modified with silsesquioxane-functionalized gold nanoparticles (AuNPs-SiPy). This nanohybrid was characterized by UV-Vis, FTIR and Raman spectroscopies, DLS, and XRD. The conditions for the immobilization of a ZIKV ssDNA probe on the electrode surface (ox-GCE-[AuNPs-SiPy]) were optimized by univariate and multivariate analysis. The optimized biosensor was characterized by CV, EIS and AFM experiments. The ZIKV target recognition was based on the variation of the charge transfer resistance (ΔRct) of the redox marker ([Fe(CN)6]3-/4-) used and the roughness (Rq) of the electrode surface. The proposed biosensor presented a LOD of 0.82â¯pmolâ¯L-1, with a linear range of 1.0 x10-12 - 1.0 x10-6â¯molâ¯L-1. Moreover, the reported device showed a suitable stability and satisfactory sensitivity and selectivity to quantify ZIKV in human serum samples, which suggests its promising clinical applications for the early diagnosis of ZIKV-associated pathologies.
Asunto(s)
Técnicas Biosensibles/métodos , Oro/química , Ácidos Nucleicos Inmovilizados/química , Nanopartículas del Metal/química , Infección por el Virus Zika/sangre , Virus Zika/aislamiento & purificación , ADN de Cadena Simple/química , Electrodos , Humanos , Límite de Detección , Compuestos de Organosilicio/química , Infección por el Virus Zika/virologíaRESUMEN
Pediatric adrenocortical carcinoma (pACC) is a rare and aggressive malignancy of high occurrence in Southern Brazil. pACC is characterized by the usual overproduction of dehydroepiandrosterone sulfate (DHEAS), whose detection in serum or plasma can be effective to the early diagnosis of the disease. Therefore, the present paper reports, for the first time, the construction and application of a label-free impedimetric immunosensor to detect DHEAS, which was based on the modification of an oxidized glassy carbon electrode with arginine-functionalized gold nanoparticles (AuNPs-ARG) and anti-DHEA IgM antibodies (ox-GCE/AuNPs-ARG/IgM). AuNPs-ARG was synthesized by a green route, and characterized by UV-VIS spectroscopy, FTIR, TEM, DLS, and XRD. The construction of ox-GCE/AuNPs-ARG/IgM was optimized through factorial design and response surface methodology. Cyclic voltammetry and electrochemical impedance spectroscopy measurements were employed to characterize the optimized immunosensor. The DHEAS detection principle was based on the variation of charge transfer resistance (∆Rct) relative to the Fe(CN)64-/3- electrochemical probe after immunoassays in the presence of the biomarker. A linear relationship between ∆Rct and DHEAS concentration was verified in the range from 10.0 to 110.0⯵gâ¯dL-1, with a LOD of 7.4⯵gâ¯dL-1. Besides the good sensitivity, the immunosensor displayed accuracy, stability, and specificity to detect DHEAS. The promising analytical performance of ox-GCE/AuNPs-ARG/IgM was confirmed by quantifying DHEAS in real patient plasma samples, with results that were comparable to the reference chemiluminescence assay. Our results suggest that the presented immunosensor can find clinical applications in the early diagnosis of pACC and to monitor DHEAS levels in other adrenal pathologies.