Technological advances for analyzing the content of organ-on-a-chip by mass spectrometry

Three-dimensional (3D) cell cultures, including organ-on-a-chip (OOC) devices, offer the possibility to mimic human physiology conditions better than 2D models. The organ-on-a-chip devices have a wide range of applications, including mechanical studies, functional validation, and toxicology investigations. Despite many advances in this field, the major challenge with the use of organ-on-a-chips relies on the lack of online analysis methods preventing the real-time observation of cultured cells. Mass spectrometry is a promising analytical technique for real-time analysis of cell excretes from organ-on-a-chip models. This is due to its high sensitivity, selectivity, and ability to tentatively identify a large variety of unknown compounds, ranging from metabolites, lipids, and peptides to proteins. However, the hyphenation of organ-on-a-chip with MS is largely hampered by the nature of the media used, and the presence of nonvolatile buffers. This in turn stalls the straightforward and online connection of organ-on-a-chip outlet to MS. To overcome this challenge, multiple advances have been made to pre-treat samples right after organ-on-a-chip and just before MS. In this review, we summarised these technological advances and exhaustively evaluated their benefits and shortcomings for successful hyphenation of organ-on-a-chip with MS

Strategies for molecular structure elucidation in static and dynamic systems

Detecting, identifying, and characterizing molecules and structures as the substance of life are essential steps toward unveiling their role as a sole entity or more commonly as a part of a larger molecular assembly for specific biological functionalities. Next, it is of pivotal importance to translate the acquired knowledge of molecular structures and their activity to a more comprehensive understanding of the biological process, such as the biochemical foundations of diseases or metabolic disorders. The aim and ultimate outcomes of this thesis were to address these two aspects by offering new analytical strategies such as focusing on the molecular structure assessment of small molecules, including drug metabolites and potential biomarkers, and drug targets. Addressing challenges encountered in protein characterization and protein interactions studies. And lastly, taking a step forward and analyzing a dynamic chemical reaction in an online fashion by mass, tandem mass, and ion mobility spectrometry

Biomaterials for the treatment of Alzheimer’s disease

Alzheimer’s disease (AD) as a progressive and fatal neurodegenerative disease represents a huge unmet need for treatment. The low efficacy of current treatment methods is not only due to low drug potency but also due to the presence of various obstacles in the delivery routes. One of the main barriers is the blood–brain barrier. The increasing prevalence of AD and the low efficacy of current therapies have increased the amount of research on unraveling of disease pathways and development of treatment strategies. One of the interesting areas for the latter subject is biomaterials and their applications. This interest originates from the fact that biomaterials are very useful for the delivery of therapeutic agents, such as drugs, proteins, and/or cells, in order to treat diseases and regenerate tissues. Recently, manufacturing of nano-sized delivery systems has increased the efficacy and delivery potential of biomaterials. In this article, we review the latest developments with regard to the use of biomaterials for the treatment of AD, including nanoparticles and liposomes for delivery of therapeutic compounds and scaffolds for cell delivery strategies

Uncovering the behaviour of ions in the gas-phase to predict the ion mobility separation of isomeric steroid compounds

Bile acids are steroid compounds involved in biological mechanisms of neurodegenerative diseases making them potential biomarkers for diagnosis or treatment. These compounds exist as structural and conformational isomers, which hinder distinguishing them in physiological processes. We aimed to develop tandem mass spectrometry-ion mobility spectrometry (MS/MS-IMS) methodologies to explore and understand the behaviour of isomeric steroids in the gas-phase and rapidly separate them. Unlike previously published ion mobility data, various isomers were investigated in mixtures to better mimic complex (pre-) clinical samples. The experimental collision cross sections (CCS)s were compared to the theoretical CCS values for an in-depth analysis of isomeric ions' behaviour in the gas-phase. Based on density-functional theory, we identified the impact of adduct positioning on the 3D conformation of enantiomers, diastereomers and structural isomers. The curling of the large side chains hedged the small differences among the isomers and lowered the CCS values. On the other hand, fragmenting off the identical side branches as well as imposing the bending of the steroid ring resulted in ion mobility differentiation. Careful data evaluation revealed the tendency of isomers to form homo-cluster in the mixture solutions and assist the separation. Our fundamental and experimental findings enable the ion mobility separation of isomeric steroids to be predicted. The introduced rapid and optimal MS/MS-IMS analytical methodology can be applied to distinguish isomeric bile acids both in a solution and potentially in patients' tissue samples, and consequently, reveal their molecular pathways

Adduct ion formation as a tool for the molecular structure assessment of ten isomers in traveling wave and trapped ion mobility spectrometry

Rationale The separation of isomeric compounds with major differences in their physiochemical and pharmacokinetic properties is of particular importance in pharmaceutical R&D. However, the structural assessment and separation of these compounds with current analytical techniques and methods are still a challenge. In this study, we describe strategies to separate the various structural and stereo-isomers. Methods The separation of ten structural and stereo-isomers was investigated using Trapped and Travelling Wave ion mobility spectrometry (TIMS and TWIMS). Different strategies including adduct ion formation with Na, Li, Ag and Cs as well as fragmentation before and after the ion mobility cell were applied to separate the isomeric compounds. Results All the counter ions (in particular Na) strongly coordinated with the test analytes in all the IMS systems. The highest resolving power was achieved for the sodium and lithium adducts using TIMS-time-of-flight (TOF). However, some separation was attained on a Synapt HDMS system with its unique potential to monitor the ion mobility of the product ions. The elution order of the adduct ions was the same in all instruments, in which, unexpectedly, the para-substituted isomer of the [M + Na](+) species had the lowest collision cross section followed by the meta- and ortho-isomers. Conclusions The formation of adduct ions could facilitate the separation of structural and even stereo-isomers by generating different molecular conformations. In addition, fragmenting isomers before or after the ion mobility cell is a valuable strategy to separate and also to assess the structures of adducts and different conformers

Cholecalciferol as Bioactive Plasticizer of High Molecular Weight Poly(D,L-Lactic Acid) Scaffolds for Bone Regeneration

Synthetic thermoplastic polymers are a widespread choice as material candidates for scaffolds for tissue engineering (TE), thanks to their ease of processing and tunable properties with respect to biological polymers. These features made them largely employed in melt-extrusion based additive manufacturing (AM), with particular application in hard-tissue engineering. In this field, high molecular weight (Mw) polymers ensuring entanglement network strength are often favorable candidates as scaffold materials because of their enhanced mechanical properties compared to lower Mw grades. However, this is accompanied by high viscosities once processed in molten conditions, which requires driving forces not always accessible technically or compatible with often chemically non-stabilized biomedical grades. When possible, this is circumvented by increasing the operating temperature, which often results in polymer chain scission and consequent degradation of properties. Additionally, synthetic polymers are mostly considered bioinert compared to biological materials and additional processing steps are often required to make them favorable for tissue regeneration. In this study, we report the plasticization of a common thermoplastic polymer with cholecalciferol, the metabolically inactive form of vitamin D3. Plasticization of the polymer allowed us to reduce its melt viscosity, and therefore the energy requirements (mechanical (torque) and heat (temperature)) for extrusion, limiting ultimately polymer degradation. Additionally, we evaluated the effect of cholecalciferol, which is more easily available than its active counterpart, on the osteogenic differentiation of mesenchymal stromal cells (hMSCs). Results indicated that cholecalciferol supported osteogenic differentiation more than the osteogenic culture medium, suggesting that hMSCs possess the enzymatic toolbox for Vitamin D3 (VD3) metabolism.</p

Evaluación estilos de aprendizaje en trabajo social

En el marco de las nuevas estrategias de aprendizaje que se desprenden de las directrices de Bolonia que persiguen una mejora del rendimiento, es clave y primordial poder evaluar todos los factores que favorecen el aprendizaje. En este trabajo presentamos una parte de la investigación realizada con alumnos de Grado de Trabajo Social centrada en el estudio de la relación entre el enfoque de aprendizaje, con la forma de regular su aprendizaje y el tipo de rendimiento. La primera parte del trabajo se ha realizado tomando como base el cuestionario CHAEA, de Alonso, Gallego y Honey (1994). Los resultados obtenidos nos permiten afirmar que existen diferencias estadísticas significativas en las puntuaciones de los cuatro estilos de aprendizaje entre los alumno

TMTHSI, a superior 7-membered ring alkyne containing reagent for strain-promoted azide-alkyne cycloaddition reactions

We describe the development of TMTH-SulfoxImine (TMTHSI) as a superior click reagent. This reagent combines a great reactivity, with small size and low hydrophobicity and compares outstandingly with existing click reagents. TMTHSI can be conveniently functionalized with a variety of linkers allowing attachment of a diversity of small molecules and (peptide, nucleic acid) biologics