Search results for "biosensor"
showing 10 items of 236 documents
Iron and iron-oxide magnetic nanoparticles as signal-amplification elements in electrochemical biosensing
2015
Abstract Growing demands for ultrasensitive biosensing have led to the development of numerous signal-amplification strategies. Based on their unique properties (i.e., electro-conductivity, bio-compatibility and ease of synthesis), various iron magnetic nanoparticles (MNPs) have proved to be an excellent nanomaterial for applications in electrochemical biosensing. This review shows how iron MNPs have made significant contributions in the development of electrochemical nanobiosensors, including immuno-, enzyme, DNA and aptamer types. More importantly, we discuss in detail different aspects of the electrochemical biosensors (e.g., modes of magnetic particles, detection techniques, analytes an…
Dendrimer-encapsulated and cored metal nanoparticles for electrochemical nanobiosensing
2014
Abstract We discuss nanosized dendrimers from the point of view of electrochemical-biosensor design. We review electrochemical biosensors based on dendrimer-encapsulated metal nanoparticles (NPs) and their various applications (e.g., measurement of small biological and toxic molecules, detection of DNA, and immunosensing of disease biomarkers). Finally, we discuss some future applications of electrochemical biosensors based on dendrimer-encapsulated metal NPs.
Enzyme-modified electrodes for biosensors and biofuel cells
2019
In biosensors and biofuel cells, it is often desirable to accelerate the electron transfer rate between the enzyme and electrode surface to improve the performance of the devices (sensitivity or power output). To this end, in this review, we focus on three important strategies available to improve the performance of enzyme-modified electrodes: the use of protein engineering, designer polymers, and the introduction of nanomaterials. Engineering the protein or proteins that constitute the biocatalytic elements allow tuning their stability, activity, and specificity. It can also allow changing the enzyme immobilization efficiency (adsorption vs. covalent immobilization, for example). If direct…
Electrochemical biosensing using hydrogel nanoparticles
2014
Abstract Biology and medicine have seen great advancements in the development of nanobiosensors capable of characterizing and quantifying biomolecules. This review reports a systematic study of the usefulness of hydrogel nanoparticles (HNPs) in the different steps of the electroanalytical process developed in electrochemical biosensing systems. We illustrate the advantages offered by HNPs in detection of analytes with representative recent examples that highlight the scientific interest in widening the use of HNPs in electrochemical biosensing methods. We review different types of HNP-based electrochemical biosensors, such as enzyme, protein, and nucleic acids, in terms of their sensing per…
Mesoporous silica-based materials for use in biosensors
2012
Abstract There have been great advancements in the development of biosensors capable of characterizing and quantifying biomolecules. This article gives an overview of the formation, the properties and the electrochemical applications of ordered mesoporous silica-based materials in electrocatalysis, electrosorption, matrix immobilization, construction of systems for controlled release of active compounds, sensors, biosensors and immunosensors. We also present a comprehensive overview of current developments and key issues in the determination of some biological molecules with particular emphasis on the evaluation of models.
Biosilica-based immobilization strategy for label-free OWLS sensors
2013
Abstract In the last years, a new group of enzymes, so-called silicateins, have been identified and characterized, which form the axial filaments of the spicules of the siliceous sponges, consisting of amorphous silica. Silicateins are able to catalyze the polycondensation and deposition of silica at mild conditions (low temperature and physiological pH). By means of these enzymes it is possible for the first time to produce silica nanostructures biocatalytically, which opens new ways for construction of biosensors. The cDNAs encoding the responsible enzymes have been isolated and the proteins can be produced in a recombinant way. Here we demonstrate the silicatein-mediated biosilica format…
Recent advances on application of peptide nucleic acids as a bioreceptor in biosensors development
2019
Abstract The analogs of DNA are unique biomedical tools that are broadly utilized to develop different types of biosensors. Peptide nucleic acids (PNA) are an individual and notable class of nucleic acid analogs due to their unique, novel physicochemical and biochemical characteristics, stability and resistance to nuclease and protease enzymes, significant interactions with complementary strands and remarkable hybridization attributes. Therefore, they are employed in the preparation and fabrication of various types of functional biosensors. In other words, immobilization of PNA as an appropriate diagnostic probe on the surface of electrochemical and optical converters lead to the fabricatio…
Photoluminescence ZnO nanorod biosensors for medical and food safety applications
2017
Photoluminescence (PL) ZnO nanorods (NR) are prospect materials for biosensor applications. They can be deposited on solid state substrates and/or dispersed in liquid media. ZnO NRs demonstrate strong UV emission (3.28–3.3 eV), which depends on surface charge, formed by adsorbed molecules. In the present work we report on ZnO NRs, deposited on glass slides, used as biosensor templates for detection food pathogens. Change of ZnO PL after interaction with biomolecules was recorded. Dependence of PL intensity vs concentration of biomolecules was obtained. In the second part, ZnO nanorods were used as PL biomarkers. A suspension of ZnO NRs, conjugated with SSEA-4 antibodies (aSSEA-4) in PBS buf…
Hydrogen peroxide sensing with horseradish peroxidase-modified polymer single conical nanochannels.
2011
Inspired from the funtioning and responsiveness of biological ion channels, researchers attempt to develop biosensing systems based on polymer and solid-state nanochannels. The applicability of these nanochannels for detection/sensing of any foreign analyte in the surrounding environment depends critically on the surface characteristics of the inner walls. Attaching recognition sites to the channel walls leads to the preparation of sensors targeted at a specific molecule. There are many nanochannel platforms for the detection of DNA and proteins, but only a few are capable of detecting small molecules. Here, we describe a nanochannel platform for the detection of hydrogen peroxide, H(2)O(2)…
Biosensors Applied to Quantification of Ethanol in Beverages
2019
Abstract The quality control in the processing of alcoholic beverages is major concern for producers and regulatory agencies, particularly for ethanol content which is mandatory in the label of alcoholic beverages in many countries. The use of biosensors can be of great interest in this context that usually requires laborious and costly protocols. Biosensors are composed by two principal components: the biological recognition element and the transducer. Particularly for ethanol evaluation, the use of alcohol dehydrogenase (ADH) or oxidase (AOX) is commonly reported in the literature which allowed the production of optical and electrochemical biosensors. These biosensors can aid in the deter…