Immunocytochemistry by Electron Spectroscopic Imaging Using Well Defined Boronated Monovalent Antibody Fragments

Contributing to the rapidly developing field of immunoelectron microscopy a new kind of markers has been created. The element boron, incorporated as very stable carborane clusters into different kinds of peptides, served as a marker detectable by electron spectroscopic imaging (ESI) - an electron microscopic technique with high-resolution potential. Covalently linked immunoreagents conspicuous by the small size of both antigen recognizing part and marker moiety are accessible by using peptide concepts for label construction and their conjugation with Fab\u27 fragments. Due to a specific labeling of the free thiol groups of the Fab\u27 fragments, the antigen binding capacity was not affected by the attachment of the markers and the resulting immunoprobes exhibited an elongated shape with the antigen combining site and the label located at opposite ends. The labeling densities observed with these reagents were found to be significantly higher than those obtained by using conventional colloidal gold methods. Combined with digital image processing and analysis systems, boron-based ESI proved to be a powerful approach in ultrastructural immunocytochemistry employing pre-and post-embedding methods

A bacteriophage-based platform for early diagnosis of Alzheimers disease

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Alzheimer’s disease (AD) is the most common neurodegenerative disease affecting a large proportion of the human population worldwide. One hallmark of AD is the increased deposition of plaques, which consist of amyloid-beta (AB) peptide, a key molecule to cause AD onset and progression. However, it is not AB immobilized in plaques, but in the still-soluble oligomeric/fibrillar form that impairs synaptic function and memory encoding. It is therefore important to develop tools that selectively target AB in oligomeric/fibrillar form, to diagnose and neutralize these detrimental AB-clusters during the early stages of the disease. Homing peptides that selectively recognize AB-oligomers and fibrils have been described: AB30-39, reactive for AB fibrils and AB33-42, reactive to fibrils and oligomers [1]. However, these peptides are unable to cross the blood-brain barrier (BBB) by themselves. To overcome this limitation, viruses became a very interesting tool given their versatility to be modified through genetic or chemical manipulation. Bacteriophages (phages), are viruses that only infect bacteria (a major advantage in terms of safety when therapeutic use in humans is envisaged). M13KE is one of the most widely used phage which has been reported as capable to cross the BBB [2]. [...]info:eu-repo/semantics/publishedVersio

Engineering of specific bacteriophages for early diagnosis of Alzheimer′s disease

Alzheimer’s disease (AD) is the most common neurodegenerative disease affecting a large proportion of the human population worldwide with great impact on social and economic level. At molecular level, AD is characterized by an increased deposition of plaques, which consist of amyloid-beta however, it is not the amyloid-beta in plaques, but amyloid-beta in soluble oligomeric form that impairs synaptic function and memory encoding. The limitations imposed by the blood-brain barrier (BBB) have hindered the development of new diagnostic/therapeutic techniques. Also, AD-treatments that target plaques have proven to be ineffective, therefore it is important to find diagnostic and therapeutic tools that selectively target amyloid-beta in oligomeric form. Peptie ligands that selectively recognize AB-oligomers are available, however they are not able to cross the BBB. To overcome this limitation, the development and application of viruses has become a very interesting tool. Bacteriophages (or phages – virus that only infect bacterial cells) can bypass the BBB and can be genetically and chemically manipulated in order to recognize and target specific biomarkers commonly used for AD diagnostic. The present work describes the development of a bacteriophage-based system that can be capable of diagnose AD at an early stage by shuttling amyloid-beta specific ligands across the BBB. Phages were genetically engineered with two peptide sequences described to selectively recognize amyloid-beta oligomers in order to target and visualize amyloid-beta aggregates in the brain. Future work will be devoted to test this system in AD-mouse models for diagnosis purposes at an early stage of the disease. If successful, this approach will provide the neuroscience community with a promising tool for AD early diagnose

Enhancing the Electrocatalytic Activity of Redox Stable Perovskite Fuel Electrodes in Solid Oxide Cells by Atomic Layer-Deposited Pt Nanoparticles

The carbon dioxide and steam co-electrolysis in solid oxide cells offers an efficient way to store the intermittent renewable electricity in the form of syngas (CO + H2), which constitutes a key intermediate for the chemical industry. The co-electrolysis process, however, is challenging in terms of materials selection. The cell composites, and particularly the fuel electrode, are required to exhibit adequate stability in redox environments and coking that rules out the conventional Ni cermets. La0.75Sr0.25Cr0.5Mn0.5O3 (LSCrM) perovskite oxides represent a promising alternative solution, but with electrocatalytic activity inferior to the conventional Ni-based cermets. Here, we report on how the electrochemical properties of a state-of-the-art LSCrM electrode can be significantly enhanced by introducing uniformly distributed Pt nanoparticles (18 nm) on its surface via the atomic layer deposition (ALD). At 850 °C, Pt nanoparticle deposition resulted in a ∼62% increase of the syngas production rate during electrolysis mode (at 1.5 V), whereas the power output was improved by ∼84% at fuel cell mode. Our results exemplify how the powerful ALD approach can be employed to uniformly disperse small amounts (∼50 μg·cm–2) of highly active metals to boost the limited electrocatalytic properties of redox stable perovskite fuel electrodes with efficient material utilization.</p