Highly sensitive and specific graphene/TiO2 impedimetric immunosensor based on plant-derived tetravalent envelope glycoprotein domain III (EDIII) probe antigen for dengue diagnosis

Central Countries' and Brazil's Contributions to Nanotechnology

Abstract:

Nanotechnology is a cornerstone of the scientific advances witnessed over the past few years. Nanotechnology applications are extensively broad, and an overview of the main trends worldwide can give an insight into the most researched areas and gaps to be covered. This document presents an overview of the trend topics of the three leading countries studying in this area, as well as Brazil for comparison. The data mining was made from the Scopus database and analyzed using the VOSviewer and Voyant Tools software. More than 44.000 indexed articles published from 2010 to 2020 revealed that the countries responsible for the highest number of published articles are The United States, China, and India, while Brazil is in the fifteenth position. Thematic global networks revealed that the standing-out research topics are health science, energy, wastewater treatment, and electronics. In a temporal observation, the primary topics of research are: India (2020), which was devoted to facing SARS-COV 2; Brazil (2019), which is developing promising strategies to combat cancer; China (2018), whit research on nanomedicine and triboelectric nanogenerators; the United States (2017) and the Global tendencies (2018) are also related to the development of triboelectric nanogenerators. The collected data are available on GitHub. This study demonstrates the innovative use of data-mining technologies to gain a comprehensive understanding of nanotechnology's contributions and trends and highlights the diverse priorities of nations in this cutting-edge field.

Electrochemical Sensors and Biosensors for Identification of Viruses: A Critical Review

Due to their life cycle, viruses can disrupt the metabolism of their hosts, causing diseases. If we want to disrupt their life cycle, it is necessary to identify their presence. For this purpose, it is possible to use several molecular-biological and bioanalytical methods. The reference selection was performed based on electronic databases (2020-2023). This review focused on electrochemical methods with high sensitivity and selectivity (53% voltammetry/amperometry, 33% impedance, and 12% other methods) which showed their great potential for detecting various viruses. Moreover, the aforementioned electrochemical methods have considerable potential to be applicable for care-point use as they are portable due to their miniaturizability and fast speed analysis (minutes to hours), and are relatively easy to interpret. A total of 2011 articles were found, of which 86 original papers were subsequently evaluated (the majority of which are focused on human pathogens, whereas articles dealing with plant pathogens are in the minority). Thirty-two species of viruses were included in the evaluation. It was found that most of the examined research studies (77%) used nanotechnological modifications. Other ones performed immunological (52%) or genetic analyses (43%) for virus detection. 5% of the reports used peptides to increase the method's sensitivity. When evaluable, 65% of the research studies had LOD values in the order of ng or nM. The vast majority (79%) of the studies represent proof of concept and possibilities with low application potential and a high need of further research experimental work.

Peptide-Based Flavivirus Biosensors: From Cell Structure to Virological and Serological Detection Methods

In tropical and developing countries, mosquito-borne diseases by flaviviruses pose a serious threat to public health. Early detection is critical for preventing their spread, but conventional methods are time-consuming and require skilled technicians. Biosensors have been developed to address this issue, but cross-reactivity with other flaviviruses remains a challenge. Peptides are essentially biomaterials used in diagnostics that allow virological and serological techniques to identify flavivirus selectively. This biomaterial originated as a small protein consisting of two to 50 amino acid chains. They offer flexibility in chemical modification and can be easily synthesized and applied to living cells in the engineering process. Peptides could potentially be developed as robust, low-cost, sensitive, and selective receptors for detecting flaviviruses. However, modification and selection of the receptor agents are crucial to determine the effectiveness of binding between the targets and the receptors. This paper addresses two potential peptide nucleic acids (PNAs) and affinity peptides that can detect flavivirus from another target-based biosensor as well as the potential peptide behaviors of flaviviruses. The PNAs detect flaviviruses based on the nucleotide base sequence of the target's virological profile via Watson-Crick base pairing, while the affinity peptides sense the epitope or immunological profile of the targets. Recent developments in the functionalization of peptides for flavivirus biosensors are explored in this Review by division into electrochemical, optical, and other detection methods.

A comprehensive review of dengue with a focus on emerging solutions for precision and timely detection

Dengue is a global health problem, caused by the dengue virus (DENV), which belongs to the Flaviviridae family of viruses. The transmission of DENV occurs through vectors, Ae. aegypti and Ae. Albopictus mosquitoes, to the human host, classifying it as a vector-borne disease. The disease incidence is increasing at an alarming rate and needs to be tackled to reduce the morbidity and mortality caused by the disease. Environmental and clinical surveillance, detection of the virus, and diagnostics are critical tools to address this issue. In this comprehensive review, we explore various diagnostic techniques and the associated challenges within the context of dengue. While we briefly touch upon dengue's epidemiology, serotypes, and pathogenesis, our primary emphasis remains on diagnostics. We delve into the intricacies of these diagnostic methods, considering both the challenges they entail and the potential they hold in terms of accuracy and accessibility. It's important to note that the review does not extensively cover clinical aspects or regional variations of the disease.

Nanomaterial surface modification toolkit: Principles, components, recipes, and applications

Surface-functionalized nanostructures are at the forefront of biotechnology, providing new opportunities for biosensors, drug delivery, therapy, and bioimaging applications. The modification of nanostructures significantly impacts the performance and success of various applications by enabling selective and precise targeting. This review elucidates widely practiced surface modification strategies, including click chemistry, cross-coupling, silanization, aldehyde linkers, active ester chemistry, maleimide chemistry, epoxy linkers, and other protein and DNA-based methodologies. We also delve into the application-focused landscape of the nano-bio interface, emphasizing four key domains: therapeutics, biosensing, environmental monitoring, and point-of-care technologies, by highlighting prominent studies. The insights presented herein pave the way for further innovations at the intersection of nanotechnology and biotechnology, providing a useful handbook for beginners and professionals. The review draws on various sources, including the latest research articles (2018-2023), to provide a comprehensive overview of the field.

Emerging Methods in Biosensing of Immunoglobin G-A Review

Human antibodies are produced due to the activation of immune system components upon exposure to an external agent or antigen. Human antibody G, or immunoglobin G (IgG), accounts for 75% of total serum antibody content. IgG controls several infections by eradicating disease-causing pathogens from the body through complementary interactions with toxins. Additionally, IgG is an important diagnostic tool for certain pathological conditions, such as autoimmune hepatitis, hepatitis B virus (HBV), chickenpox and MMR (measles, mumps, and rubella), and coronavirus-induced disease 19 (COVID-19). As an important biomarker, IgG has sparked interest in conducting research to produce robust, sensitive, selective, and economical biosensors for its detection. To date, researchers have used different strategies and explored various materials from macro- to nanoscale to be used in IgG biosensing. In this review, emerging biosensors for IgG detection have been reviewed along with their detection limits, especially electrochemical biosensors that, when coupled with nanomaterials, can help to achieve the characteristics of a reliable IgG biosensor. Furthermore, this review can assist scientists in developing strategies for future research not only for IgG biosensors but also for the development of other biosensing systems for diverse targets.

A novel sandwich impedimetric immunosensor for detection of apolipoprotein-A1 based on the gold nanoparticle-hybridized mercapto-β-cyclodextrin-Pb(II) metal-organic framework

A novel sandwich electrochemical impedimetric immunosensor was proposed to detect apolipoprotein-A1 (Apo-A1), a common biomarker for bladder cancer. The molybdenum disulfide/graphene quantum dot (MoS₂/GQD) nanocomposites were modified on the surface of a glassy carbon electrode (GCE) and used to immobilize the biotinylated antibody (Ab₁) with the help of chitosan and glutaraldehyde (denoted as BSA/Ab₁/CHIT/MoS₂/GQD/GCE). Pb(II)-thiol-β-cyclodextrin metal-organic framework (denoted as Pb-MOF) was synthesized with lead metal ions and thiol-β-cyclodextrin ligands by a one-pot solvothermal method, and then, gold nanoparticles were modified on the surface of Pb-MOF (Pb-MOF-AuNPs) by Au-S bond, which was used as signal label for the recombinant antibody (Ab₂). When the immunosensor of BSA/Ab₁/CHIT/MoS₂/GQD/GCE reacted with Apo-A1, Pb-MOF-AuNPs-Ab₂/BSA was connected to the electrode when immunoreaction occurred, and an immune sandwich structure was formed, which led to significantly increased charge transfer resistance of electrochemical probe for ferrocyanide (II)/(III) within the frequency range 10^-1 ~ 10⁵ Hz at 5 mV amplitude and the potential of 0.180 V (vs. SCE). Based on this principle, the quantitative detection of Apo-A1 was established. The relative change of electrochemical resistance and the logarithmic value of Apo-A1 concentration showed a linear relationship with a linear coefficient of 0.9989 in the range 1.00 pg mL^-1 and 1.00 μg mL^-1 with the limit of detection of 0.30 pg mL^-1. The selectivity, repeatability, and other performance of the proposed immunosensor were also investigated. The immunosensor was successfully applied to the detection of real serum and urine samples with recovery in the range 96.4 ~ 109.1% (RSD < 3.8%), indicating that it could be helpful for the clinical diagnosis of bladder cancer.

Plant-based expression and characterization of SARS-CoV-2 virus-like particles presenting a native spike protein

We have investigated the use of transient expression to produce virus-like particles (VLPs) of severe acute respiratory syndrome coronavirus 2, the causative agent of COVID-19, in Nicotiana benthamiana. Expression of a native form of the spike (S) protein, either alone or in combination with the envelope (E) and membrane (M) proteins, all of which were directed to the plant membranes via their native sequences, was assessed. The full-length S protein, together with degradation products, could be detected in total protein extracts from infiltrated leaves in both cases. Particles with a characteristic 'crown-shaped' or 'spiky' structure could be purified by density gradient centrifugation. Enzyme-linked immunosorbent assays using anti-S antibodies showed that threefold higher levels of VLPs containing the full-length S protein were obtained by infiltration with S alone, compared to co-infiltration of S with M and E. The S protein within the VLPs could be cleaved by furin in vitro and the particles showed reactivity with serum from recovering COVID-19 patients, but not with human serum taken before the pandemic. These studies show that the native S protein expressed in plants has biological properties similar to those of the parent virus. We show that the approach undertaken is suitable for the production of VLPs from emerging strains and we anticipate that the material will be suitable for functional studies of the S protein, including the assessment of the effects of specific mutations. As the plant-made material is noninfectious, it does not have to be handled under conditions of high containment.

A One-Step Electrochemical Aptasensor Based on Signal Amplification of Metallo Nanoenzyme Particles for Vascular Endothelial Growth Factor

In this study, a one-step electrochemical aptasensor was developed to detect the biomarker vascular endothelial growth factor (VEGF), an important protein in the pathogenesis of many retinal diseases, including age-related macular degeneration, diabetic retinopathy, retinopathy of prematurity, and retinal vein occlusion. The aptamer has a good affinity and can rapidly identify and capture VEGF based on its unique structure. We designed a VEGF aptasensor based on the aptamer recognition and complex metallo nanoenzyme particles as an electron exchange center and bridge between capture DNA and electrode. The aptamers maintained the hairpin structure to avoid nonspecific surface adsorption and expose the capture sequence outwards when the target was inexistent. Conversely, the aptamers opened the hairpin structure to release space to accomplish binding between VEGF and DNA, resulting in increased impedance. The performance of the electrochemical aptasensor is detected by electrochemical impedance spectroscopy (EIS). The limit of detection by EIS was as low as 8.2 pg ml-1, and the linear range was 10 pg ml-1-1 μg ml-1. The electrochemical aptasensor also showed high specificity and reproducibility.

A label-free amperometric immunosensor with improved electrocatalytic 3D braided AuPtCu-SWCNTs@MoS2-rGO for human growth differentiation factor-15 detection

Growth differentiation factor-15 (GDF-15) is a member of the transforming growth factor-β family. GDF-15 is overexpressed in cardiovascular diseases and has become a novel biomarker for these diseases. In this study, we fabricated a label-free electrochemical immunosensor for sensitive detection of GDF-15. Briefly, a three-dimensional braided composite of AuPtCu-SWCNTs@MoS₂-rGO (denoted A@M), which served as a label-free immunosensor platform, was obtained by wrapping single-walled carbon nanotubes (SWCNTs) with trimetallic nanoflowers (AuPtCu NFs) woven on a three-dimensional network nanostructure composed of Molybdenum disulfide (MoS₂) and reduced graphene oxide (rGO) nanosheets. This optimization improved the ability of the platform to immobilize antibodies, accelerated the reduction of hydrogen peroxide, and promoted the migration rate of electrons on the electrode surface, thereby further amplifying the electrical signal and improving the sensitivity. The constructed sensor exhibited high sensitivity over a wide linear range from 1 pg mL^-1 to 50 ng mL^-1, with a low detection limit of 0.825 pg mL^-1 for GDF-15. The fabricated label-free immunosensor exhibits satisfactory reproducibility, selectivity, and stability. The detection of actual samples was successful, enabling a broad scope of application in the early diagnosis, prognosis, and treatment of cardiovascular diseases.

Sensitive electrochemical immunosensor for CYFRA21-1 detection based on AuNPs@MoS2@Ti3C2Tx composites

Cytokeratin fragment antigen 21-1 (CYFRA21-1) is a sensitive marker for detecting non-small cell lung cancer (NSCLC). Ti₃C₂T_x modified by gold nanoparticles (AuNPs) and molybdenum disulfide (MoS₂) were synthesized for the first time to obtain the AuNPs@MoS₂@Ti₃C₂T_x composites, which have large specific surface area and good electrocatalytic properties. A novel electrochemical immunoassay for sensitive detection of CYFRA21-1 was developed by loading a large quantity of secondary antibodies (Ab₂) and toluidine blue (TB) on the surface of the material as signal probe, and Nafion-AuNPs mixture as electrode material. When the electrochemical response value of CYFRA21-1 increased linearly within the concentration range of 0.5 pg mL^-1-50 ng mL^-1, the detection limit can reach as low as 0.03 pg mL^-1. In addition, the experimental results showed that the biosensor had the potential to rapidly detect CYFRA21-1 in the complex samples such as patient serum, and had a broad application prospect in the early diagnosis and monitoring of NSCLC.

Point-of-Care Based Electrochemical Immunoassay for Epstein-Barr Virus Detection

This work describes a label-free electrochemical immunosensor for the sensing of Epstein-Barr virus (EBV) with high sensitivity. First, a monolayer of 1,6-hexanedithiol (HDT) was fabricated on the screen-printed electrode surface by the interaction between sulfur atoms and SPE. AuNPs can be modified on the electrode by the Au-S bond formed between the HDT-free group and Au atom in AuNPs. Protein A is then adsorbed onto AuNPs. Several parameters were optimized. The optimum concentration of protein A is 0.6 mg/mL. The optimum immobilization time for protein A is 90 min. The optimum concentration of antibody is 80 μg/mL. The optimum immobilization time for antibody is 90 min. Directional immobilization of EBV antibody is achieved by high affinity binding of protein A to the Fc segment of antibody. When antigen specifically binds to antibody, the formation of immune complexes blocks electron transfer of [Fe(CN)6]^4-/3- and is reflected in the detection of cyclic voltammetry/electrochemical impedance spectroscopy. The detection range is 1 pg/mL-l00 ng/mL with a LOD of 0.1 pg/mL. In addition, the proposed sensor exhibited an excellent antiinterference property.

Development and Optimization of an Enzyme Immunoassay to Detect Serum Antibodies against the Hepatitis E Virus in Pigs, Using Plant-Derived ORF2 Recombinant Protein

Hepatitis E is an emerging global disease, mainly transmitted via the fecal-oral route in developing countries, and in a zoonotic manner in the developed world. Pigs and wild boar constitute the primary Hepatitis E virus (HEV) zoonotic reservoir. Consumption of undercooked animal meat or direct contact with infected animals is the most common source of HEV infection in European countries. The purpose of this study is to develop an enzyme immunoassay (EIA) for the detection of anti-hepatitis E virus IgG in pig serum, using plant-produced recombinant HEV-3 ORF2 as an antigenic coating protein, and also to evaluate the sensitivity and specificity of this assay. A recombinant HEV-3 ORF2 110-610_6his capsid protein, transiently expressed by pEff vector in Nicotiana benthamiana plants was used to develop an in-house HEV EIA. The plant-derived HEV-3 ORF2 110-610_6his protein proved to be antigenically similar to the HEV ORF2 capsid protein and it can self-assemble into heterogeneous particulate structures. The optimal conditions for the in-house EIA (iEIA) were determined as follows: HEV-3 ORF2 110-610_6his antigen concentration (4 µg/mL), serum dilution (1:50), 3% BSA as a blocking agent, and secondary antibody dilution (1:20 000). The iEIA developed for this study showed a sensitivity of 97.1% (95% Cl: 89.9-99.65) and a specificity of 98.6% (95% Cl: 92.5-99.96) with a Youden index of 0.9571. A comparison between our iEIA and a commercial assay (PrioCHECK™ Porcine HEV Ab ELISA Kit, ThermoFisher Scientific, MA, USA) showed 97.8% agreement with a kappa index of 0.9399. The plant-based HEV-3 ORF2 iEIA assay was able to detect anti-HEV IgG in pig serum with a very good agreement compared to the commercially available kit.

Dengue Detection: Advances in Diagnostic Tools from Conventional Technology to Point of Care

The dengue virus (DENV) is a vector-borne flavivirus that infects around 390 million individuals each year with 2.5 billion being in danger. Having access to testing is paramount in preventing future infections and receiving adequate treatment. Currently, there are numerous conventional methods for DENV testing, such as NS1 based antigen testing, IgM/IgG antibody testing, and Polymerase Chain Reaction (PCR). In addition, novel methods are emerging that can cut both cost and time. Such methods can be effective in rural and low-income areas throughout the world. In this paper, we discuss the structural evolution of the virus followed by a comprehensive review of current dengue detection strategies and methods that are being developed or commercialized. We also discuss the state of art biosensing technologies, evaluated their performance and outline strategies to address challenges posed by the disease. Further, we outline future guidelines for the improved usage of diagnostic tools during recurrence or future outbreaks of DENV.

Advances in emergent biological recognition elements and bioelectronics for diagnosing COVID-19

Coronaviruses pose a serious threat to public health. Tremendous efforts are dedicated to advance reliable and effective detection of coronaviruses. Currently, the coronavirus disease 2019 (COVID-19) diagnosis mainly relies on the detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genetic materials by using reverse transcription-polymerase chain reaction (RT-PCR) assay. However, simpler and more rapid and reliable alternatives are needed to meet high demand during the pandemic. Biosensor-based diagnosis approaches become alternatives for selectively and rapidly detecting virus particles because of their biorecognition elements consisting of biomaterials that are specific to virus biomarkers. Here, we summarize biorecognition materials, including antibodies and antibody-like molecules, that are designed to recognize SARS-CoV-2 biomarkers and the advances of recently developed biosensors for COVID-19 diagnosis. The design of biorecognition materials or layers is crucial to maximize biosensing performances, such as high selectivity and sensitivity of virus detection. Additionally, the recent representative achievements in developing bioelectronics for sensing coronavirus are included. This review includes scholarly articles, mainly published in 2020 and early 2021. In addition to capturing the fast development in the fields of applied materials and biodiagnosis, the outlook of this rapidly evolving technology is summarized. Early diagnosis of COVID-19 could help prevent the spread of this contagious disease and provide significant information to medical teams to treat patients.