Centri-voltammetry and biocentri-voltammetry: a review

Centri-voltammetry and biocentri-voltammetry are techniques that combine centrifugation with voltammetry. This review covers (a) definitions; (b) experimental (cell) configurations; (c) effects of centrifugation parameters; and (d) applications of the method to the determination of heavy metals and biological molecules. Specific examples include applications to the determination of xanthine, acetylcholine esterase activity, and of acetyl choline.

Cubic phases in biosensing systems

Incorporation of membrane proteins with retained activity in artificial membranes for use in membrane-based sensors has attracted scientists for decades. This review briefly summarises general concepts on relevant cubic phases with and without incorporated proteins and provides some insight into the development of biosensors where bicontinuous cubic phases are used for incorporation of an enzyme. Some new data on impedance characterisation of a supported cubic phase are also shown. An efficient membrane-based electrochemical biosensor requires that the analyte has free access to the immobilised membrane protein and that regeneration of the catalysing enzyme is fast. Long-term stability of the system is also necessary for the biosensor to find applications outside the research laboratory. These basic concepts are discussed in the review along with presentation of those biosensing systems based on cubic phases that are reported in the literature.     

Nano-enabled biosensing systems for intelligent healthcare: towards COVID-19 management

Biosensors are emerging as efficient (sensitive and selective) and affordable analytical diagnostic tools for early-stage disease detection, as required for personalized health wellness management. Low-level detection of a targeted disease biomarker (pM level) has emerged extremely useful to evaluate the progression of disease under therapy. Such collected bioinformatics and its multi-aspects-oriented analytics is in demand to explore the effectiveness of a prescribed treatment, optimize therapy, and correlate biomarker level with disease pathogenesis. Owing to nanotechnology-enabled advancements in sensing unit fabrication, device integration, interfacing, packaging, and sensing performance at point-of-care (POC) has rendered diagnostics according to the requirements of disease management and patient disease profile i.e. in a personalized manner. Efforts are continuously being made to promote the state of art biosensing technology as a next-generation non-invasive disease diagnostics methodology. Keeping this in view, this progressive opinion article describes personalized health care management related analytical tools which can provide access to better health for everyone, with overreaching aim to manage healthy tomorrow timely. Considering accomplishments and predictions, such affordable intelligent diagnostics tools are urgently required to manage COVID-19 pandemic, a life-threatening respiratory infectious disease, where a rapid, selective and sensitive detection of human beta severe acute respiratory system coronavirus (SARS-COoV-2) protein is the key factor.     

Trends in biosensing platforms for SARS-CoV-2 detection: A critical appraisal against standard detection tools

In this ongoing theme of coronavirus disease 2019 (COVID-19) pandemic, highly sensitive analytical testing platforms are extremely necessary to detect SARS-CoV-2 RNA and antiviral antibodies. To limit the viral spread, prompt and precise diagnosis is crucial to facilitate treatment and ensure effective isolation. Accurate detection of antibodies (IgG and IgM) is imperative to understand the prevalence of SARS-CoV-2 in public and to inspect the proportion of immune individuals. In this review, we demonstrate and evaluate some tests that have been used commonly to detect SARS-CoV-2. These include nucleic acid and serological tests for the detection of SARS-CoV-2 RNA and specific antibodies in infected people. Moreover, the vitality of biosensing technologies emphasizing on optical and electrochemical biosensors toward the detection of SARS-CoV-2 has also been discussed here. The early diagnosis of COVID-19 based on detection of reactive oxygen species overproduction because of virus-induced dysfunctioning of lung cells has also been highlighted.     

Breath biosensing: using electrochemical enzymatic sensors for detection of biomarkers in human breath

Detection of biomarkers for disease by noninvasive methods is critical for the early diagnosis and screening of disease, enabling prompt treatment. Breath biosensors are a viable option as the exhaled breath contains several biomarkers linked to lung cancer, oxidative stress, diabetes, and other diseases. Breath analysis has been achieved by advanced analytical techniques such as gas chromatography and infrared spectroscopy. However, electrochemical enzymatic breath biosensors offer a cost-effective, sensitive platform for biomarker detection without complex analysis and interpretation by trained laboratory personnel. This review aims to summarize recent advances in the field of electrochemical enzymatic breath biosensors and offer future opportunities from other applications of nonelectrochemical enzymatic breath biosensors.     

The nanomaterials and recent progress in biosensing systems: A review

1. Download : Download high-res image (87KB)
2. Download : Download full-size image

     

Engineered cells as biosensing systems in biomedical analysis

Over the past two decades there have been great advances in biotechnology, including use of nucleic acids, proteins, and whole cells to develop a variety of molecular analytical tools for diagnostic, screening, and pharmaceutical applications. Through manipulation of bacterial plasmids and genomes, bacterial whole-cell sensing systems have been engineered that can serve as novel methods for analyte detection and characterization, and as more efficient and cost-effective alternatives to traditional analytical techniques. Bacterial cell-based sensing systems are typically sensitive, specific and selective, rapid, easy to use, low-cost, and amenable to multiplexing, high-throughput, and miniaturization for incorporation into portable devices. This critical review is intended to provide an overview of available bacterial whole-cell sensing systems for assessment of a variety of clinically relevant analytes. Specifically, we examine whole-cell sensing systems for detection of bacterial quorum sensing molecules, organic and inorganic toxic compounds, and drugs, and for screening of antibacterial compounds for identification of their mechanisms of action. Methods used in the design and development of whole-cell sensing systems are also reviewed.     

Rapid DNA electrochemical biosensing platform for label-free potentiometric detection of DNA hybridization

This paper described a novel electrochemical DNA biosensor for rapid specific detection of nucleic acids based on the sulfonated polyaniline (SPAN) nanofibre and cysteamine-capped gold nanoparticle (CA-G_NP) layer-by-layer films. A precursor film of 3-mercaptopropionic acid (MPA) was firstly self-assembled on the Au electrode surface. CA-G_NP was covalently deposited on the Au/MPA electrode to obtain a stable substrate. SPAN nanofibre and CA-G_NP were alternately layer-by-layer assembled on the stable substrate by electrostatic force. Cyclic voltammetry was used to monitor the consecutive growth of the multilayer films by utilizing [Fe(CN)₆]^3−/4− as the redox indicator. The (CA-G_NP/SPAN)_n films showed satisfactory ability of electron transfer and excellent redox activity in neutral media. Negatively charged probe ssDNA was immobilized on the outer layer of the multilayer film (CA-G_NP) through electrostatic affinity. Chronopotentiometry and electrochemical impedance spectroscopy were employed to obtain the direct electrochemical readout for probe ssDNA immobilization and hybridization using [Fe(CN)₆]^3−/4− in solution as the mediator. While electrochemical impedance spectroscopy led to the characterization of the electron-transfer resistance at the electrode, chronopotentiometry provided the total resistance at the interfaces of the modified electrodes. A good correlation between the total electrode resistances and the electron-transfer resistances at the conducting supports was found. Chronopotentiometry was suggested as a rapid transduction means (a few seconds). Based on the (CA-G_NP/SPAN)_n films, the target DNA with 20-base could be detected up to 2.13 × 10⁻¹³ mol/L, and the feasibility for the detection of base-mismatched DNA was also demonstrated.     

Electrosynthesized polymers for biosensing

This tutorial review briefly surveys the chronological evolution of biosensor concepts based on electrogenerated polymers. The most common procedures of biomolecule immobilization are classified as direct electropolymerization, physical entrapment, covalent linkage, and anchoring by affinity interactions via electropolymerized films. These are discussed, and recent bioanalytical applications are described. The discussion emphasizes the use of templates for controlling the formation of nanowires and composite polymers. Recent advances in the design of three-dimensional biological architectures are also highlighted.     

Photonics-on-a-chip: recent advances in integrated waveguides as enabling detection elements for real-world, lab-on-a-chip biosensing applications

By leveraging advances in semiconductor microfabrication technologies, chip-integrated optical biosensors are poised to make an impact as scalable and multiplexable bioanalytical measurement tools for lab-on-a-chip applications. In particular, waveguide-based optical sensing technology appears to be exceptionally amenable to chip integration and miniaturization, and, as a result, the recent literature is replete with examples of chip-integrated waveguide sensing platforms developed to address a wide range of contemporary analytical challenges. As an overview of the most recent advances within this dynamic field, this review highlights work from the last 2-3 years in the areas of grating-coupled, interferometric, photonic crystal, and microresonator waveguide sensors. With a focus towards device integration, particular emphasis is placed on demonstrations of biosensing using these technologies within microfluidically controlled environments. In addition, examples of multiplexed detection and sensing within complex matrices--important features for real-world applicability--are given special attention.     

Peroxidase-mimicking DNAzymes for biosensing applications: a review

DNAzymes are single stranded DNA molecules that exhibit catalytic activity and are exploited in medicine, biology and material sciences. Development in this area is related to the many advantages of DNAzymes over conventional protein enzymes, such as thermal stability and simpler preparation. DNAzymes with peroxidase-like activity have recently attracted great interest. To assure such catalytic activity, oligonucleotides have to adopt a G-quadruplex structure, which can bind the hemin molecule. This system facilitates a redox reaction between the target molecule and hydrogen peroxide, which results in the appearance of an oxidized target molecule (product). DNAzymes with peroxidase-mimicking activity have great potential in bioanalytical chemistry. This review presents fundamentals concerning the design and engineering of DNAzymes with peroxidase-like activity, describes their properties and spectral characteristics and shows how DNAzymes can contribute to bioanalytical research. Examples of bioanalytical applications of DNAzymes with peroxidase-like activity include nucleic acid probes with DNAzyme labels for the detection of specific DNA sequences in colorimetric or chemiluminescent assays. Assays for telomerase or methyltransferase activity, which are potential targets in anticancer therapy, are also described in this review. Other applications include the determination of metal cations such as Ag(+), K(+), Hg(2+), Pb(2+) or Cu(2+) and amplified detection of small molecules such as adenosine, cocaine or AMP and proteins such as lysozyme or thrombin. In the last decade, DNAzymes have become part of numerous applications in many areas of science from chemistry to biology to medicine.     

Examination of performance of glassy carbon paste electrode modified with gold nanoparticle and xanthine oxidase for xanthine and hypoxanthine detection

A composite electrode was prepared by modifying glassy carbon microparticles with gold nanoparticles (Au-nps) and xanthine oxidase enzyme (XOD) for xanthine (X) and hypoxanthine (Hx) detection. After the optimization of the system for X, the biosensor was characterized for X and Hx. A linearity was obtained in the concentration range between 5.00 × 10⁻⁷ and 1.00 × 10⁻⁵ M for X with equation of y = 0.24x + 0.712 and 5.00 × 10⁻⁶ to 1.50 × 10⁻⁴ M for Hx, with equation of y = 0.014x + 0.575, respectively. Obtained results were compared to X and/or Hx biosensors including/not including Au-np in the structure. The developed system was also applied for detection of Hx in canned tuna fish sample and very promising results were obtained.     

Carbon nanotubes for electrochemical biosensing

The aim of this review is to summarize the most relevant contributions in the development of electrochemical (bio)sensors based on carbon nanotubes in the last years.Since the first application of carbon nanotubes in the preparation of an electrochemical sensor, an increasing number of publications involving carbon nanotubes-based sensors have been reported, demonstrating that the particular structure of carbon nanotubes and their unique properties make them a very attractive material for the design of electrochemical biosensors.The advantages of carbon nanotubes to promote different electron transfer reactions, in special those related to biomolecules; the different strategies for constructing carbon nanotubes-based electrochemical sensors, their analytical performance and future prospects are discussed in this article.     

Shape-coded silica nanotubes for biosensing

Shape-coded silica nanotubes (SNTs) were fabricated on the basis of template synthesis as a new dispersible microarray system. The template synthesis of shape-coded SNTs begins with the fabrication of a porous alumina film that has well-defined cylindrical pores with two or more different diameter segments by multistep anodization of an aluminum substrate. Then, SNTs were fabricated with a surface sol-gel method that can control the wall thickness of SNTs on the single-nanometer level. Attractively, the difference in optical reflectance between the segmented parts of individual silica nanotube makes it very convenient to identify each nanotube and enables these shape-coded SNTs to work as coding materials for biosensing.     

Microneedle-based electrochemical devices for transdermal biosensing: a review

Many research efforts over the last decade have been devoted to the development of microneedle-based diagnostic devices for minimally invasive transdermal biosensing and for long-term health monitoring. Transdermal biosensing via microneedle allows the development of minimally invasive easy-to-use point-of-care biodevices. The main objective of this short review is to provide a general overview of the most immediate and relevant progress in microneedle-based transdermal biosensing in the last five years. A critical analysis of the recent literature is finally presented.     

Microneedles-based electrochemical sensors: New tools for advanced biosensing

Electrochemical biosensors are used worldwide as analytical tools from laboratory applications to market products. The performance of electrochemical sensing can be boosted by adopting the microneedle (MN) geometry as an innovative configuration of standard electrodes. MNs can be miniaturized, easily functionalized, and properly designed for specific aim monitoring, but most of all, they allow a low invasive controlling tool for growth and for environment influence in plant and a painless door to human body fluids where target analytes can be detected, overcoming the natural barrier of the skin. In this review, the very recent developments in MN-based electrochemical biosensing published in the literature are summarized.     

pH-metric detection of alkaline phosphatase activity as a novel biosensing platform

A detection of alkaline phosphatase (ALP, EC 3.1.3.1) activity by the monitoring of pH changes caused by the biocatalytic action of the enzyme has been experimentally examined. Enzymatically catalyzed hydrolysis of monofluorophosphate has been found to be the best basis for such measurements. Protolytic equilibria connected with the developed biosensing system were recognized and the optimal conditions for the assay have been found. Advantages and disadvantages of the developed (bio)sensing scheme have been discussed. The prototype of pH-ALP based enzyme electrode has been demonstrated. Potential utility of such substrate-enzyme-sensor system for the development of a new group of biosensors has been announced.     

Tautomerism of xanthine and alloxanthine: A model for substrate recognition by xanthine oxidase

Summary Tautomerism of neutral xanthine and alloxanthine has been examined both in the gas phase and in aqueous solution. The tautomeric preference in the gas phase has been studied by means of semiempirical and ab initio quantum-mechanical computations with inclusion of correlation effects at the Møller-Plesset level, and from density-functional calculations. The influence of solvent on the relative stability between tautomers has been estimated from self-consistent reaction field calculations performed with different models. The results provide a detailed picture of tautomerism for these biologically relevant purine bases. The functional implications in the recognition by xanthine oxidase are analyzed from inspection of the interaction patterns of the most stable tautomeric forms. A model for the recognition of these purine derivatives in the enzyme binding site is discussed.