Henok Baye Habtamu

Bio: Henok Baye Habtamu is an academic researcher from University of Bordeaux. The author has contributed to research in topics: Biosensor & Glucose oxidase. The author has an hindex of 3, co-authored 3 publications receiving 74 citations.

A Sensitive Electrochemiluminescence Immunosensor for Celiac Disease Diagnosis Based on Nanoelectrode Ensembles

Abstract: We report here the design of a novel immunosensor and its application for celiac disease diagnosis, based on an electrogenerated chemiluminescence (ECL) readout, using membrane-templated gold nanoelectrode ensembles (NEEs) as a detection platform. An original sensing strategy is presented by segregating spatially the initial electrochemical reaction and the location of the immobilized biomolecules where ECL is finally emitted. The recognition scaffold is the following: tissue transglutaminase (tTG) is immobilized as a capturing agent on the polycarbonate (PC) surface of the track-etched templating membrane. It captures the target tissue transglutaminase antibody (anti-tTG), and finally allows the immobilization of a streptavidin-modified ruthenium-based ECL label via reaction with a suitable biotinylated secondary antibody. The application of an oxidizing potential in a tri-n-propylamine (TPrA) solution generates an intense and sharp ECL signal, suitable for analytical purposes. Voltammetric and ECL analy...

Miniaturized Enzymatic Biosensor via Biofunctionalization of the Insulator of Nanoelectrode Ensembles

Abstract: An innovative second generation enzymatic microbiosensor was developed exploiting the properties of nanoelectrode ensembles (NEEs) prepared by electroless gold deposition in track-etched polycarbonate (PC) membranes. As a case study, a miniaturized glucose biosensor was developed and characterized. The micro-NEE glucose biosensor was obtained by immobilizing glucose oxidase (GOx) on the nonconductive PC component of the NEE, while the Au nanoelectrodes were used exclusively as transducers. (Ferrocenylmethyl)trimethylammonium cation (FA+) was used as the redox mediator. The immobilization of GOx on the PC did not affect the electrochemical performances of the NEE nor the catalytic activity of the enzyme. The proposed biosensor showed outstanding analytical performances with a detection limit of 36 µM. The nanostructured biosensor was miniaturized down to a micro-NEE with overall radius of 400 µm, without any degradation of the analytical performances.

Electrochemical immunosensor based on nanoelectrode ensembles for the serological analysis of IgG-type tissue transglutaminase

Abstract: Celiac disease (CD) is a gluten-dependent autoimmune disorder affecting a significant percentage of the general population, with increasing incidence particularly for children. Reliable analytical methods suitable for the serological diagnosis of the disorder are urgently required for performing both the early diagnosis and the follow-up of a patient adhering to a gluten-free diet. Herein we report on the preparation and application of a novel electrochemical immunosensor based on the use of ensembles of gold nanoelectrodes (NEEs) for the detection of anti-tissue transglutaminase (anti-tTG), which is considered one reliable serological marker for CD. To this end, we take advantage of the composite nature of the nanostructured surface of membrane-templated NEEs by functionalizing the polycarbonate surface of the track-etched membrane with tissue transglutaminase. Incubation of the functionalized NEE in anti-tTG samples results in the capture of the anti-tTG antibody. Confirmation of the recognition event is achieved by incubating the NEE with a secondary antibody labelled with horseradish peroxidase (HRP): in the presence of H2O2 as substrate and hydroquinone as redox mediator, an electrocatalytic current is indeed generated whose increment is proportional to the amount of anti-tTG captured from the sample. The optimized sensor allows a detection limit of 1.8 ng mL−1, with satisfactory selectivity and reproducibility. Analysis of serum samples from 28 individuals, some healthy and some affected by CD, furnished analytical results comparable with those achieved by classical fluoroenzyme immunoassay (FEIA). We note that the NEE-based immunosensor developed here detects the IgG isotype of anti-tTG, while FEIA detects the IgA isotype, which is not a suitable diagnostic marker for IgA-deficient patients.

Recent Advances in Electrochemiluminescence Analysis.

Abstract: ■ CONTENTS Novel ECL Systems 358 Novel Organic Luminophores 358 Novel Inorganic Luminophores 359 Novel Nanomaterial System 360 Detection Methodologies and Signaling Amplification Strategies 361 General Detection Methodologies 361 Novel Signal Amplification Strategies 361 ECL Applications 362 Metal Ions Detection 362 Small Molecules Detection 362 ECL Immunoassay 363 ECL Genosensors 365 ECL Cytosensors 366 Conclusions and Outlooks 368 Author Information 369 Corresponding Author 369 ORCID 369 Author Contributions 369 Notes 369 Biographies 369 Acknowledgments 369 References 369

Single Cell Electrochemiluminescence Imaging: From the Proof-of-Concept to Disposable Device-Based Analysis

Abstract: We report here the development of coreactant-based electrogenerated chemiluminescence (ECL) as a surface-confined microscopy to image single cells and their membrane proteins. Labeling the entire cell membrane allows one to demonstrate that, by contrast with fluorescence, ECL emission is only detected from fluorophores located in the immediate vicinity of the electrode surface (i.e., 1–2 μm). Then, to present the potential diagnostic applications of our approach, we selected carbon nanotubes (CNT)-based inkjet-printed disposable electrodes for the direct ECL imaging of a labeled plasma receptor overexpressed on tumor cells. The ECL fluorophore was linked to an antibody and enabled to localize the ECL generation on the cancer cell membrane in close proximity to the electrode surface. Such a result is intrinsically associated with the unique ECL mechanism and is rationalized by considering the limited lifetimes of the electrogenerated coreactant radicals. The electrochemical stimulus used for luminescence g...

Ceria Doped Zinc Oxide Nanoflowers Enhanced Luminol-Based Electrochemiluminescence Immunosensor for Amyloid-β Detection

Abstract: In this work, ceria doped ZnO nanomaterials with flower-structure (Ce:ZONFs) were prepared to construct a luminol-based electrochemiluminescence (ECL) immunosensor for amyloid-β protein (Aβ) detection. Herein, carboxyl groups (−COOH) covered Ce:ZONFs were synthesized by a green method with lysine as reductant. After that, Ce:ZONFs-based ECL nanocomposite was prepared by combining the luminophore of luminol and Ce:ZONFs via amidation and physical absorption. Luminol modified on Ce:ZONFs surface could generate a strong ECL signal under the assistance of reactive oxygen species (ROSs) (such as OH• and O2•–), which were produced by a catalytic reaction between Ce:ZONFs and H2O2. It was worth noticing that a quick Ce4+ ↔ Ce3+ reaction in this doped material could increase the rate of electron transfer to realize the signal amplification. Subsequently, the luminol functionalized Ce:ZONFs (Ce:ZONFs-Lum) were covered by secondary antibody (Ab2) and glucose oxidase (GOD), respectively, to construct a novel Ab2 bio...

Essential Role of Electrode Materials in Electrochemiluminescence Applications

Abstract: The phenomenon of electrochemiluminescence (ECL) is luminescence triggered by electrochemical reactions at electrodes. Heterogeneous electron transfers are deeply dependent on electrode materials, therefore, besides the usual parameters, the right choice of the electrode is a crucial point to address properly in order to maximize the emission efficiency. Many different electrodes have been studied, from metallic -platinum or gold- through transparent indium-doped tin oxide to carbon based electrodes, and others, such as paper based and boron doped diamond. This review summarizes results of ECL at different electrode surfaces, disclosing the relative advantages and disadvantages, with a particular attention to the reference Ru(bpy)32+/TPrA coreactant system. In other words, we offer an insight to recognize and select the optimal electrode material for the ECL systems of interest with particular emphasis on the biosensing applications.