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5 figures.-- Supporting information available., The question of whether exosome lipids can be considered as potential cancer biomarkers faces our current limited knowledge of their composition. This is due to the difficulty in isolating pure exosomes, the variability of the biological sources from which they are extracted, and the uncertainty of the methods for lipid characterization. Here, we present a procedure to isolate exosomes and obtain a deep, repeatable, and rapid phospholipid (PL) composition of their lipid extracts, from embryonic murine fibroblasts (NIH-3T3 cell line) and none (B16-F1) and high (B16-F10) metastatic murine skin melanoma cells. The analytical method is based on High Performance Thin-Layer Chromatography with Ultraviolet and fluorescence densitometry and coupled to Electrospray (ESI)-tandem Mass Spectrometry (MS). Under the conditions described in this work, separation and determination of PL classes, (sphingomyelins, SM; phosphatidylcholines, PC; phosphatidylserines, PS; and phosphatidylethanolamines, PE) were achieved, expressed as µg PL/100 µg exosome protein, obtained by bicinchoninic acid assay (BCA). A detailed structural characterization of molecular species of each PL class was performed by simultaneous positive and negative ESI-MS and MS/MS directly from the chromatographic plate, thanks to an elution-based interface., Financial support for this project was provided by DGA-FEDER (E25_20R, N&SB), AES PI21/00036, CSIC 202180E076, ISCIII PI19/01007, DGA E25-20R, and ERC Advanced Grant CADENCE (grant No. ERC-2016-ADG-742684).

6 figures, 2 tables.-- Supplementary information available.-- © 2021. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/, Identification of 19 molecular species of globotriaosylceramides (Gb3) in extracts from a Fabry's plasma patient and a healthy control was performed by High-Performance Thin-Layer Chromatography (HPTLC)-densitometry and online coupling to Mass Spectrometry (MS). Separation was carried out on LiChrospher plates using Automated Multiple Development (AMD). Densitometry was performed on twin plates by combining detection in the visible at 550 nm, through previous on-plate orcinol derivatization, and by Ultraviolet 190 nm, using a non-impregnated plate. The latter was directly coupled to an ion-trap mass spectrometer through an automated elution-based interface. Gb3 molecular species, which were identified by HPTLC- Electrospray Mass Spectrometry (+)-MS and confirmed by MS/MS or HPTLC-Atmospheric Pressure Chemical Ionization Mass Spectrometry (+)-MS, are: five isoforms of saturated Gb3; seven isoforms of methylated Gb3; and seven species with two additional double bonds. Twelve of these species were previously reported as biomarkers of Fabry's lysosomal disorder using a Liquid Chromatography-MS-based method, and the other seven are structurally similar, closely related to them. Saturated Gb3 isoforms migrated on LiChrospher plate in one of the separated peaks corresponding to the migration zone of ceramide trihexosides standard. Instead, methylated and unsaturated Gb3 species co-migrated with sphingomyelin species. Ion intensity ESI-MS profiles show that saturated Gb3 species in Fabry's plasma were in higher concentration than in control sample. Before applying the Thin-Layer Chromatography (TLC)-MS interface on HPTLC separated peaks, its positioning precision was first studied using ceramide tri-hexosides as model compound. This provided information on Gb3 peak broadening and splitting during its migration., This work was supported by DGA-FEDER (E25_17R, N&SB). One of us (J.G.) thanks to Spanish Plan Nacional I+D+i (CTQ2016-76846-R project).

9 figures, 2 multimedia components.-- © 2021. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/, An enzymatic method for the direct (without pretreatment) minimally invasive tyramine determination in cheese is proposed. Colorimetric test strips containing tyramine oxidase (TAO), peroxidase and 3,3′,5,5′-tetramethylbenzidine (Q-TAO), allow tyramine determination through the RGB chromatic coordinates of the observed blue colour (LOD = 2.6·10−6 M, LOQ = 8.7·10−6 M, RSD% (n = 5; 1.8·10−4 M) = 3.2%). The strips are inserted in the sample for 2 min and then the RGB coordinates are measured using a smartphone. Previously, these Q-TAO strips have been also optimized for tyramine determination in cheese extract. To do that, a spectrophotometric method in solution for tyramine determination in cheese extracts has been developed, which included an in-depth study of the indicating reaction; this study has allowed to gain new information about the spectroscopic properties of different TMB species and, which it is more important, to detect cross-reactions between TAO and TMB species. A mathematical model has also been developed which relate the RGB signals obtained with the tyramine concentrations, the instrumental characteristics of the smartphone and the spectroscopic properties of the absorbing product of the enzymatic reaction., This work was supported by the MINECO of Spain (projects CTQ2016-76846R and PID2019-105408 GB-I00) and by Research groups funded by DGA-FEDER (group E25_17R, N&SB).

12 Figuras, Here we present a route for non-covalent functionalization of carboxylated multi-walled carbon nanotubes and graphene oxide with novel two-dimensional peptide assemblies. We show that self-assembled amino-terminated biantennary and tetraantennary oligoglycine peptides (referred to as tectomers) effectively coat carboxylated multi-walled carbon nanotubes and also strongly interact with graphene oxide due to electrostatic interactions and hydrogen bonding as the driving force, respectively. The resulting hybrids can be made into free-standing conducting composites or applied in the form of thin, pH-switchable bioadhesive coatings onto graphene oxide fibers. Monitoring of cell viability of pancreatic cell lines, seeded on those CNT hybrids, show that they can be used as two- and three-dimensional scaffolds to tissue engineer tumour models for studying ex vivo the tumour development and response to treatment. This highly versatile method in producing pH-responsive hybrids and coatings offers an attractive platform for a variety of biomedical applications and for the development of functional materials such as smart textiles, sensors and bioelectronic devices., Authors thank the Fundación Domingo Martínez (Ayudas a la Investigación 2013), the Spanish Ministerio de Economía y Competitividad MINECO (Plan Nacional de I+D+I, Project CTQ2012-035535), DGA (Grupo Consolidado de Investigación Aplicada ref T08), CSIC Intramural Entorno Project, JMR ARC Future Fellowship (FT130100380), Engineering and Physical Sciences Research Council (EPSRC) grant no. EP/K031562, University of Sussex Strategic Development Fund, H2020-MSCA-ITN-2014 Enabling Excellence project, and the College of Applied Medical Sciences Research Center and the Deanship of Scientific Research at King Saud University for supporting this research.

8 Figuras.- 2 Tablas.- This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Liquid Chromatography and Related Technologies on 3th April 2019, available online: http://www.tandfonline.com/10.1080/10826076.2018.1561465, High-performance thin-layer chromatography (HPTLC)-densitometry was directly combined with electrospray (ESI) tandem mass spectrometry for obtaining rapid and relevant structural identification of phospholipids (PL) species associated to membrane proteins (MP), in non-sulfur, purple bacteria having photosynthetic activity. Thus, species belonging to phosphatidylcholines (PC), phosphatidylethanolamines (PE), cardiolipins (CL) and phosphatidylglycerols (PG) associated to MP were investigated in bacterial membrane extracts from Rhodobacter (Rb.) blasticus, Rhodospirillum (R.) rubrum and Rhodobaca (Rbc.) bogoriensis, as well as those which are bound to a purified MP-photosynthetic complex from Rbc. bogoriensis. PL-classes were separated using a 7-step gradient-solvent sequence with a previous acid plate preconditioning, using Automated Multiple Development. Band zones of the plate corresponding to PL classes were selected to ensure their direct transfer to ion-trap MS equipment through an elution-based interface. Under the studied conditions, ESI+-MS spectra of PC and CL mostly showed sodium adducts ([M + Na]+) and [M-2H + 3Na]+, respectively, when recorded from the plate. The respective sodium adducts were fragmented in the ion-trap, and sodium remained as the charge of the fragment ions, thus being useful for their structural identification through MS/MS. ESI--MS and MS/MS spectra of CL were also obtained as [M-2H]2−, as well as those of PE and PG species as [M-H]- and [M]−, respectively. In this way, relative composition profiles of each studied PL-class by ESI-MS, and further identification of individual PL and the molecular species belonging to each of them by MS/MS were obtained., This work was supported by the DGA-ESF under project E25_17R.

1 table., Berberine is a yellow alkaloid naturally produced by a diversity of plants. It is extracted from the roots, rhizome, and stem bark of several plants. This natural product has been used for centuries in the Chinese medicinal herb. Berberine presents a wide range of pharmacological applications such as antidiabetic, hypolipidemic, antihypertensive, anti-inflammatory, antioxidant, antidepressant, anticancer, antidiarrheal, hepatoprotective, and, above all, antimicrobial. It has been tested clinically in the treatment of oriental sore, diarrhea, trachoma, diabetes mellitus type 2, hypercholesterolemia, and congestive cardiac failure. This alkaloid is also used in the treatment of gastric and inflammatory diseases and more recently is being investigated for its application in neurology, cardiology, and oncology.

6 Figuras., Many chemical compounds, including nonfluorescent ones, induce changes in the fluorescence spectra of certain probes, such as berberine cation and Reichardt's betaine, both in the absence and the presence of solvent, that affect almost exclusively emission intensity. In this work, the application of fluorescence detection by intensity changes (FDIC) to HPLC and TLC chromatographic systems with fluorescence detectors has been studied. FDIC detection is of special interest in detecting nonfluorescent analytes, either in HPLC or in TLC mode. It does not involve covalent interactions, and the dielectric permittivity (ε) of the medium plays an important role. The balance between nonspecific and specific interactions produces either an increase or a decrease in fluorescence intensity. Therefore, the influence of chromatographic conditions and chemical structure of analytes on the sign and magnitude of fluorescence peaks for sample detection in HPLC and TLC systems has been discussed. In general, probe nature and concentration determine response and detection sensitivity for a given sample in TLC and HPLC. As solubility and fluorescence properties in solvents determine the operating conditions for a FDIC probe in HPLC mode, nature and flows of mobile phase and solvent are important for chromatographic response and detection sensitivity., Authors thank the Spanish Ministerio de Ciencia y Tecnología (MCyT) and Ministerio de Educación y Ciencia for financial support (projects PPQ2001-2388 and CTQ2005-00227/PPQ). E.M.G. acknowledges MCyT for a grant.