Sub-femtomolar detection of HIV-1 gene using DNA immobilized on composite platform reinforced by a conductive polymer sandwiched between two nanostructured layers: A solid signal-amplification strategy

MOF@COF Heterostructure Hybrid for Dual-Mode Photoelectrochemical-Electrochemical HIV-1 DNA Sensing

We developed a novel metal-organic framework (MOF)@covalent-organic framework (COF) hybrid with a hierarchical nanostructure and excellent photoactivity, which further acted as the bifunctional platform of a dual-mode photoelectrochemical (PEC) and electrochemical (EC) biosensor for detecting HIV-1 DNA via immobilizing the HIV-1 DNA probe. First, the presynthesized Cu-MOF nanoellipsoids were used as the template for the in situ growth of the COF network, which was synthesized using copper-phthalocyanine tetra-amine (CoPc-TA) and 2,9-bis[p-(formyl)phenyl]-1,10-phenanthroline as building blocks through the Schiff base condensation. In view of the large specific surface area, abundant reserved amino group, excellent electrochemical activity, and high photoactivity, the obtained Cu-MOF@CuPc-TA-COF heterostructure not only can serve as the sensitive platform for anchoring the HIV-1 DNA probe strands but also can be utilized as the signal transducers for PEC and EC biosensors. Thereby, the constructed biosensor shows the sensitive and selective analysis ability toward the HIV-1 target DNA via the complementary hybridization between probe and target DNA strands. The dual-mode PEC and EC measurements revealed that the Cu-MOF@CuPc-TA-COF-based biosensor displayed a wide linear detection range from 1 fM to 1 nM and an extremely low limit of detection (LOD) of 0.07 and 0.18 fM, respectively. In addition, the dual-mode PEC-EC biosensor also demonstrated remarkable selectivity, high stability, good reproducibility, and preferable regeneration ability, as well as acceptable applicability, for which the detected HIV-1 DNA in human serum showed good consistency with real concentrations. Thereby, the present work can open a new dual-mode PEC-EC platform for detecting HIV-1 DNA based on the porous-organic framework heterostructure.

Evolution of nucleic acids biosensors detection limit III

This review is an update of two previous ones focusing on the limit of detection of electrochemical nucleic acid biosensors allowing direct detection of nucleic acid target (miRNA, mRNA, DNA) after hybridization event. A classification founded on the nature of the electrochemical transduction pathway is established. It provides an overall picture of the detection limit evolution of the various sensor architectures developed during the last three decades and a critical report of recent strategies.

Gold nanoparticles in virus detection: Recent advances and potential considerations for SARS-CoV-2 testing development

Viruses are infectious agents that pose significant threats to plants, animals, and humans. The current coronavirus disease 2019 pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has spread globally and resulted in over 2 million deaths and immeasurable financial losses. Rapid and sensitive virus diagnostics become crucially important in controlling the spread of a pandemic before effective treatment and vaccines are available. Gold nanoparticle (AuNP)‐based testing holds great potential for this urgent unmet biomedical need. In this review, we describe the most recent advances in AuNP‐based viral detection applications. In addition, we discuss considerations for the design of AuNP‐based SARS‐CoV‐2 testings. Finally, we highlight and propose important parameters to consider for the future development of effective AuNP‐based testings that would be critical for not only this COVID‐19 pandemic, but also potential future outbreaks.

This article is categorized under:

Diagnostic Tools > Biosensing

Diagnostic Tools > In Vitro Nanoparticle‐Based Sensing

Signal amplification of novel sandwich-type genosensor via catalytic redox-recycling on platform MWCNTs/Fe3O4@TMU-21 for BRCA1 gene detection

The MWCNTs/Fe₃O₄@TMU-21 as a novel electrochemical sandwich-type genosensor was fabricated to detect the BRCA1 gene using the redox-cycling ferrocene functionalized reporter label probe (r-Fc-DNA). In the designed genosensor, the capture probe (cDNA) and r-Fc-DNA were used to detect the BRCA1 gene in sandwich-type genosensor, in which DNA sequences are well -hybridized with the BRCA1 gene (t-DNA). The cDNA was immobilized on the multiwall carbon nanotube and metal-organic framework with Fe₃O₄ nanoparticle core, which is the sensor platform. Target DNA was assayed by redox-recycling reporter probe (r-Fc-DNA) using the electro-catalytic activity of ferri/ferrocyanide, which results in significantly enhanced the oxidation peak current of r-Fc-DNA. The electrochemical redox cycling led to a high signal-to-noise ratio for gene assay. MWCNTs and Fe₃O₄@TMU-21 were applied to increase the platform conductivity and suitable binding of the recognition elements. This constructed genosensor plays an influential role in increasing the sensitivity of BRCA1 gene sequence recognition. So that under optimal conditions, this genosensor illustrated a wide linear range from 1.0×10^-15 to 1.0×10^-10 M with a detection limit of 0.57 × 10^-15 M. Moreover, the genosensor exhibited high selectivity, stability, and reproducibility. The obtained recoveries (between 91 and 105%) of the BRCA1 gene assay in human blood samples satisfactory, which can be used for BRCA1 gene measurement in the laboratory.

Electrochemical Biosensors for the Detection of SARS-CoV-2 and Other Viruses

The last few decades have been plagued by viral outbreaks that present some of the biggest challenges to public safety. The current coronavirus (COVID-19) disease pandemic has exponentiated these concerns. Increased research on diagnostic tools is currently being implemented in order to assist with rapid identification of the virus, as mass diagnosis and containment is the best way to prevent the outbreak of the virus. Accordingly, there is a growing urgency to establish a point-of-care device for the rapid detection of coronavirus to prevent subsequent spread. This device needs to be sensitive, selective, and exhibit rapid diagnostic capabilities. Electrochemical biosensors have demonstrated these traits and, hence, serve as promising candidates for the detection of viruses. This review summarizes the designs and features of electrochemical biosensors developed for some past and current pandemic or epidemic viruses, including influenza, HIV, Ebola, and Zika. Alongside the design, this review also discusses the detection principles, fabrication techniques, and applications of the biosensors. Finally, research and perspective of biosensors as potential detection tools for the rapid identification of SARS-CoV-2 is discussed.

Recent developments in carbon-based two-dimensional materials: synthesis and modification aspects for electrochemical sensors

This review (162 references) focuses on two-dimensional carbon materials, which include graphene as well as its allotropes varying in size, number of layers, and defects, for their application in electrochemical sensors. Many preparation methods are known to yield two-dimensional carbon materials which are often simply addressed as graphene, but which show huge variations in their physical and chemical properties and therefore on their sensing performance. The first section briefly reviews the most promising as well as the latest achievements in graphene synthesis based on growth and delamination techniques, such as chemical vapor deposition, liquid phase exfoliation via sonication or mechanical forces, as well as oxidative procedures ranging from chemical to electrochemical exfoliation. Two-dimensional carbon materials are highly attractive to be integrated in a wide field of sensing applications. Here, graphene is examined as recognition layer in electrochemical sensors like field-effect transistors, chemiresistors, impedance-based devices as well as voltammetric and amperometric sensors. The sensor performance is evaluated from the material's perspective of view and revealed the impact of structure and defects of the 2D carbon materials in different transducing technologies. It is concluded that the performance of 2D carbon-based sensors is strongly related to the preparation method in combination with the electrical transduction technique. Future perspectives address challenges to transfer 2D carbon-based sensors from the lab to the market. Graphical abstract Schematic overview from synthesis and modification of two-dimensional carbon materials to sensor application.

Nanotechnology based strategies for HIV-1 and HTLV-1 retroviruses gene detection

Early detection of retroviruses including human T-cell lymphotropic virus and human immunodeficiency virus in the human body is indispensable to prevent retroviral infection propagation and improve clinical treatment. Until now, diverse techniques have been employed for the early detection of viruses. Traditional methods are time-consuming, resource-intensive, and laborious performing. Therefore, designing and constructing a selective and sensitive diagnosis system to detect serious diseases is highly demanded. Genetic detection with high sensitivity has striking significance for the early detection and remedy of disparate pathogenic diseases. The nucleic acid biosensors are based on the identification of specific DNA sequences in biological samples. Nanotechnology has an important impact on the development of sensitive biosensors. Different kinds of nanomaterials include nanoparticles, nanoclusters, quantum dots, carbon nanotubes, nanocomposites, etc., with different properties have been used to improve the performance of biosensors. Recently, DNA nanobiosensors are developed to provide simple, fast, selective, low-cost, and sensitive detection of infectious diseases. In this paper, the research progresses of nano genosensors for the detection of HIV-1 and HTLV-1 viruses, based on electrochemical, optical, and photoelectrochemical platforms are overviewed.

Impedimetric determination of Cs(I) using AuNPs@PoPD-DB24C8: A targeted molecular-scale perturbation

Most attributes of the bulk materials, especially in the solid-state, are directly dictated by a manner by which the molecules are ordered. Thus, it is expected that the possibility of controlling these structural orders would allow predominating some particular physical properties. The methodology used in this work follows the molecular scale perturbation occurred by Cs⁺ ion within a ternary composite of dibenzo-24-crown-8 (DB24C8), poly ortho-phenylenediamine (PoPD) and gold nanoparticles (AuNPs). Hypothetically, two former substances were respectively employed as recognition element and conductive platform to establish a monolithic structure that resembles supramolecular synthon in solid-state. The third precursor was Au(III) that carries out a dual role including vulcanization of the polymeric units via creating quinoid rings and solid signal amplification by deposition of AuNPs at the welded points. This strategy affords an intertwined ternary composite in which the electronical properties of the system can be directly affected by lowest agitation sensed by the recognition element, DB24C8, making the supported transducer capable of monitoring trace amount of Cs⁺ ion by Faradaic impedance spectroscopy (FIS) and single-frequency measurements (SFM). The fabricated sensor showed a signal change against Cs⁺ ion over the linear range of 0.6-25.0 nM with a detection limit of 0.37 nM (S/N = 3). Density functional theory (DFT) studies were used to explore the possible recognition mechanism, by which the incorporation of Cs⁺ ion meaningfully dispersed the structural order of the ternary system.

The cooperative interaction of triplex forming oligonucleotides on DNA-triplex formation at electrode surface: Molecular dynamics studies and experimental evidences

An extensive study on cooperative interaction of Triplex Forming Oligonucleotides (TFOs) with a double strand DNA, to form a triplex-DNA structure at electrode surface, is here reported. The cooperative effect on triplex structure formation was assumed by the higher binding enthalpy value, calculated for the interaction between the duplex DNA structure and the TFO1 and TFO2 probes (-67.3 KJ/mol), respect the sum of the single duplex-TFO1 and duplex-TFO2 interactions (-47.0 kJ/mol). The formation of triplex-DNA structure was proven by kinetic modelling study performed using the Luzar and Chandler model. The results indicate that after 500 ns from interaction, H-bonds between the base pairs in the double strand DNA are weaken while new H-bonds between the TFOs and duplex DNA are formed. Molecular dynamic (MD) simulations indicate that the TFOs sequence distance (138 bps) and the amount of TA*T triplet units are the keystones for the effectiveness of the cooperative effect, reaching for the selected target a minimum of energy value of -19452.6 kJ/mol. The MD data were experimentally corroborated by electrochemical measurements, detecting a HBV-clone genome at TFOs modified electrode surface. The interaction was electrochemical transduced by an intercalative Osmium based compound. The Langmuir isotherm model reports for the forming triplex DNA an association constant value of about 2.9 × 10¹⁶M^-1, this high value could be attributed to the synergic contribution of the TFOs cooperative effect and to the rigid circular duplex structure. Finally, AFM and SEM investigations suggest the formation of a triplex-DNA structure at electrode surface, consisting in circles of about 1.5 um in diameter with asymmetric stranded thickness. This finding data paving the way to future development of advanced miniaturized DNA computing and biosensors.

Beta-cyclodextrin-functionalized CdS nanorods as building modules for ultrasensitive photoelectrochemical bioassay of HIV DNA

Nowadays, acquired immunodeficiency syndrome has become a formidable danger to human health, and its early diagnosis is urgent need with the increasing quantity of patients around the world. Herein, we first synthesized beta-cyclodextrin-functionalized CdS nanorods (β-CD@CdS NRs) with high stability and desirable photo-electricity activity, and served as easy-to-assemble building modules to design a novel photoelectrochemical biosensor for human immune deficiency virus (HIV) DNA detection by coupling with catalytic hairpin assembly (CHA)-mediated biocatalytic precipitation and the host-guest interaction between adamantine (ADA) and β-CD. In the presence of HIV DNA, CHA process was triggered with the aid of hairpin DNA1 and ADA-labelled hairpin DNA2, and then generated large amounts of G-quadruplex, which could be formed hemin/G-quadruplex DNAzyme to catalyze 4-chloro-1-naphthol to generate insoluble precipitation on photoelectrode surface, followed by the decreased photocurrent response due to the corresponding stereo-hindrance effect. Under optimized conditions, this biosensor exhibited wide linear dynamic range (10 fM - 1 nM) and low detection limit of 1.16 fM, as well as high sensitivity, excellent stability, and satisfactory feasibility in human-serum samples. Moreover, the prepared β-CD@CdS NRs could be applied to the construction of other advanced sensing platform, showing great prospect in clinical diagnostics.

HIV biosensors for early diagnosis of infection: The intertwine of nanotechnology with sensing strategies

Human immunodeficiency virus (HIV) is a lentivirus that leads to acquired immunodeficiency syndrome (AIDS). With increasing awareness of AIDS emerging as a global public health threat, different HIV testing kits have been developed to detect antibodies (Ab) directed toward different parts of HIV. A great limitation of these tests is that they can not detect HIV antibodies during early virus infection. Therefore, to overcome this challenge, a wide range of biosensors have been developed for early diagnosis of HIV infection. A significant amount of these studies have been focused on the application of nanomaterials for improving the sensitivity and accuracy of the sensing methods. Following an introduction into this field, a first section of this review covers the synthesis and applicability of such nanomaterials as metal nanoparticles (NPs), quantum dots (QDs), carbon-based nanomaterials and metal nanoclusters (NCs). A second larger section covers the latest developments concerning nanomaterial-based biosensors for HIV diagnosis, with paying a special attention to the determination of CD4⁺ cells as a hall mark of HIV infection, HIV gene, HIV p24 core protein, HIV p17 peptide, HIV-1 virus-like particles (VLPs) and HIV related enzymes, particularly those that are passed on from the virus to the CD⁴⁺ T lymphocytes and are necessary for viral reproduction within the host cell. These studies are described in detail along with their diverse principles/mechanisms (e.g. electrochemistry, fluorescence, electromagnetic-piezoelectric, surface plasmon resonance (SPR), surface enhanced Raman spectroscopy (SERS) and colorimetry). Despite the significant progress in HIV biosensing in the last years, there is a great need for the development of point-of-care (POC) technologies which are affordable, robust, easy to use, portable, and possessing sufficient quantitative accuracy to enable clinical decision making. In the final section, the focus is on the portable sensing devices as a new standard of POC and personalized diagnostics.