Water-Soluble Bimodal Magnetic-Fluorescent Radical Dendrimers as Potential MRI-FI Imaging Probes.

Dual or multimodal imaging probes have become potent tools for enhancing detection sensitivity and accuracy in disease diagnosis. In this context, we present a bimodal imaging dendrimer-based structure that integrates magnetic and fluorescent imaging probes for potential applications in magnetic resonance imaging and fluorescence imaging. It stands out as one of the rare examples where bimodal imaging probes use organic radicals as the magnetic source, despite their tendency to entirely quench fluorophore fluorescence.

New Approaches for Basophil Activation Tests Employing Dendrimeric Antigen-Silica Nanoparticle Composites.

In vitro cell activation through specific IgE bound to high-affinity receptors on the basophil surface is a widely used strategy for the evaluation of IgE-mediated immediate hypersensitivity reactions to betalactams. Cellular activation requires drug conjugation to a protein to form a large enough structure displaying a certain distance between haptens to allow the cross-linking of two IgE antibodies bound to the basophil's surface, triggering their degranulation. However, no information about the size and composition of these conjugates is available.

Pyrene Functionalized Norbornadiene-Quadricyclane Fluorescent Photoswitches: Characterization of their Spectral Properties and Application in Imaging of Amyloid Beta Plaques.

This study presents the synthesis and characterization of two fluorescent norbornadiene (NBD) photoswitches, each incorporating two conjugated pyrene units. Expanding on the limited repertoire of reported photoswitchable fluorescent NBDs, we explore their properties with a focus on applications in bioimaging of amyloid beta (Aβ) plaques. While the fluorescence emission of the NBD decreases upon photoisomerization, aligning with what has been previously reported, for the first time we observed luminescence after irradiation of the quadricyclane (QC) isomer.

New Insights into Acylhydrazones / Isomerization: An Experimental and Theoretical Approach.

A family of acylhydrazones have been prepared and characterized with the aim of investigating their potential as information storage systems. Their well-established synthetic methodologies allowed for the preparation of seven chemically stable acylhydrazones in excellent yields that have been photophysically and photochemically characterized. In addition, DFT and TD-DFT calculations have been performed to gain more insights into the structural, energetic and photophysical properties of the / isomers.

NanoFN10: A High-Contrast Turn-On Fluorescence Nanoprobe for Multiphoton Singlet Oxygen Imaging.

An "off-on" fluorescent nanoprobe for near-infrared multiphoton imaging of singlet oxygen has been developed. The nanoprobe comprises a naphthoxazole fluorescent unit and a singlet-oxygen-sensitive furan derivative attached to the surface of mesoporous silica nanoparticles. In solution, the fluorescence of the nanoprobe increases upon reaction with singlet oxygen both under one- and multiphoton excitation, with fluorescence enhancements up to 180-fold.

Substrate adhesion determines migration during mesenchymal cell condensation in chondrogenesis.

Mesenchymal condensation is a prevalent morphogenetic transition that is essential in chondrogenesis. However, the current understanding of condensation mechanisms is limited. In vivo, progenitor cells directionally migrate from the surrounding loose mesenchyme towards regions of increasing matrix adherence (the condensation centers), which is accompanied by the upregulation of fibronectin.

Nanoscale ligand density modulates gap junction intercellular communication of cell condensates during chondrogenesis.

To unveil the influence of cell-matrix adhesions in the establishment of gap junction intercellular communication (GJIC) during cell condensation in chondrogenesis. Previously developed nanopatterns of the cell adhesive ligand arginine-glycine-aspartic acid were used as cell culture substrates to control cell adhesion at the nanoscale. chondrogenesis of mesenchymal stem cells was conducted on the nanopatterns.

Synthetic antigenic determinants of clavulanic acid induce dendritic cell maturation and specific T cell proliferation in patients with immediate hypersensitivity reactions.

Background: Immediate drug hypersensitivity reactions (IDHRs) to clavulanic acid (CLV) have increased in the last decades due to a higher consumption alongside amoxicillin (AX). Due to its chemical instability, diagnostic procedures to evaluate IDHRs to CLV are difficult, and current in vitro assays do not have an optimal sensitivity. The inclusion of the specific metabolites after CLV degradation, which are efficiently recognised by the immune system, could help to improve sensitivity of in vitro tests.

Amoxicillin Haptenation of -Enolase is Modulated by Active Site Occupancy and Acetylation.

Allergic reactions to antibiotics are a major concern in the clinic. -lactam antibiotics are the class most frequently reported to cause hypersensitivity reactions. One of the mechanisms involved in this outcome is the modification of proteins by covalent binding of the drug (haptenation).

Multiepitope Dendrimeric Antigen-Silica Particle Composites as Nano-Based Platforms for Specific Recognition of IgEs.

β-lactam antibiotics (BLs) are the drugs most frequently involved in drug hypersensitivity reactions. However, current diagnostic tests have limited sensitivity, partly due to a poor understanding of drug-protein conjugates that both induce the reactions and are immunologically recognized. Dendrimeric Antigen-Silica particle composites (DeAn@SiO), consisting on nanoparticles decorated with BL-DeAns are promising candidates for improving the clinical diagnostic practice.

Photophysical properties and bioimaging application of an aminonaphthalimide-squaraine non-conjugated system.

An aminonaphthalimide-squaraine non-conjugated system was designed and synthetized with the purpose of preparing fluorescent molecule in the 650-700 nm region that could operate via energy transfer (ET) between covalently linked naphthalimide and squaraine chromophores. The photophysical properties of the new fluorescent system were explored with the aim of understanding the ET in one- and two-photon excitation modes. The spectroscopic techniques employed in the characterization includes; absorption, fluorescence, quantum yields and fluorescence lifetime measurements in different solvents.

Rapid amplitude-modulation of a diarylethene photoswitch: en route to contrast-enhanced fluorescence imaging.

A water soluble diarylethene (DAE) derivative that displays exceptionally intense fluorescence from the colorless open form has been synthesized and characterized using UV/vis spectroscopy and fluorescence microscopy. We show that the bright emission from the open form can be rapidly switched using amplitude modulated red light, that is, by light at wavelengths longer than those absorbed by the fluorescent species. This is highly appealing in any context where undesired background fluorescence disturbs the measurement, , the autofluorescence commonly observed in fluorescence microscopy.

The Role of Benzylpenicilloyl Epimers in Specific IgE Recognition.

The high prevalence of allergy to β-lactam antibiotics is a worldwide issue. Accuracy of diagnostic methods is important to prove tolerance or allergy, with skin test considered the best validated method for diagnosing immediate reactions to β-lactams. Although drug provocation test is the reference standard, it cannot be performed in highly risk reactions or in those with positive skin tests.

Role of nanostructures in allergy: Diagnostics, treatments and safety.

Nanotechnology is science, engineering and technology conducted at the nanoscale, which is about 1-100 nm. It has led to the development of nanomaterials, which behave very differently from materials with larger scales and can have a wide range of applications in biomedicine. The physical and chemical properties of materials of such small compounds depend mainly on the size, shape, composition and functionalization of the system.

Spontaneous macrocyclization through multiple dynamic cyclic aminal formation.

The use of aminals in dynamic covalent chemistry is slightly underexplored, probably due to their inherent instability. Here we report the spontaneous [2+2] macrocyclization of tetrakis(aminals). Their unexpected stability and structural modularity, the dynamic nature of the connections and their water tolerance make them appealing systems for future applications as stimulus-responsive materials.

Biotin-Labelled Clavulanic Acid to Identify Proteins Target for Haptenation in Serum: Implications in Allergy Studies.

Clavulanic acid (CLV) and amoxicillin, frequently administered in combination, can be independently involved in allergic reactions. Protein haptenation with β-lactams is considered necessary to activate the immune system. The aim of this study was to assess the suitability of biotinylated analogues of CLV as probes to study protein haptenation by this β-lactam.

Toward Two-Photon Absorbing Dyes with Unusually Potentiated Nonlinear Fluorescence Response.

The combination of two two-photon-induced processes in a Förster resonance energy transfer (FRET)-operated photochromic fluorene-dithienylethene dyad lays the foundation for the observation of a quartic dependence of the fluorescence signal on the excitation light intensity. While this photophysical behavior is predicted for a four-photon absorbing dye, the herein proposed approach opens the way to use two-photon absorbing dyes, reaching the same performance. Hence, the spatial resolution limit, being a critical parameter for applications in fluorescence imaging or data storage with common two-photon absorbing dyes, is dramatically improved.

The Janus Role of Adhesion in Chondrogenesis.

Tackling the first stages of the chondrogenic commitment is essential to drive chondrogenic differentiation to healthy hyaline cartilage and minimize hypertrophy. During chondrogenesis, the extracellular matrix continuously evolves, adapting to the tissue adhesive requirements at each stage. Here, we take advantage of previously developed nanopatterns, in which local surface adhesiveness can be precisely tuned, to investigate its effects on prechondrogenic condensation.

ARADyAL: The Spanish Multidisciplinary Research Network for Allergic Diseases.

Thematic cooperative health research networks (RETICS) are organizational structures promoted by the Instituto de Salud Carlos III of the Spanish Ministry of Science with the objective of carrying out cooperative research projects addressing challenges of general interest for society as a whole in the field of health care. The RETICS of Asthma, Adverse Drug Reactions, and Allergy (ARADyAL) received funding in 2016 for a 5-year program (2017-2021). ARADyAL integrates basic and clinical research in the areas of allergy, immunology, genetics, nanomedicine, pharmacology, and chemistry, with special interest in research on new biomarkers and the design and evaluation of new interventions for allergic patients with severe phenotypes.

Cyanine-Like Boronic Acid-Derived Salicylidenehydrazone Complexes (Cy-BASHY) for Bioimaging Applications.

Boronic acid-derived salicylidenehydrazone complex (BASHY) dyes with a polymethine backbone were designed to yield efficient red-emitting and two-photon absorbing fluorophores that can be used as markers for astrocytes. The dyes are chemically stable in aqueous solution and do not undergo photodecomposition. Their photophysical properties can be electronically fine-tuned and thereby adapted to potentially different imaging situations and requirements.

RGD-Dendrimer-Poly(L-lactic) Acid Nanopatterned Substrates for the Early Chondrogenesis of Human Mesenchymal Stromal Cells Derived from Osteoarthritic and Healthy Donors.

Aiming to address a stable chondrogenesis derived from mesenchymal stromal cells (MSCs) to be applied in cartilage repair strategies at the onset of osteoarthritis (OA), we analyzed the effect of arginine-glycine-aspartate (RGD) density on cell condensation that occurs during the initial phase of chondrogenesis. For this, we seeded MSC-derived from OA and healthy (H) donors in RGD-dendrimer-poly(L-lactic) acid (PLLA) nanopatterned substrates (RGD concentrations of 4 × 10, 10, 2.5 × 10, and 10 w/w), during three days and compared to a cell pellet conventional three-dimensional culture system.