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5 figures.-- Supplementary information available., Heterostructures of two-dimensional (2D) materials using graphene and MoS2 have enabled both pivotal fundamental studies and unprecedented sensing properties. These heterosystems are intriguing when graphene and MoS2 are interfaced with 2D sheets that emulate biomolecules, such as amino-terminated oligoglycine self-assemblies (known as tectomers). The adsorption of tectomer sheets over graphene and MoS2 modulates the physicochemical properties through electronic charge migration and mechanical stress transfer. Here, we present a systematic study by Raman spectroscopy and tectomer-functionalised scanning probe microscopy to understand mechanical strain, charge transfer and binding affinity in tectomer/graphene and tectomer/MoS2 hybrid structures. Raman mapping reveals distinctive thickness dependence of tectomer-induced charge transfer to MoS2, showing p-doping on monolayer MoS2 and n-doping on multilayer MoS2. By contrast, graphene is n-doped by tectomer independently of layer number, as confirmed by x-ray photoelectron spectroscopy. The interfacial adhesion between the amino groups and 2D materials are further explored using tectomer-functionalised probe microscopy. It is demonstrated here that these probes have potential for chemically sensitive imaging of 2D materials, which will be useful for mapping chemically distinct domains of surfaces and the number of layers. The facile tectomer-coating approach described here is an attractive soft-chemistry strategy for high-density amine-functionalisation of atomic force microscopy probes, therefore opening promising avenues for sensor applications., We would like to acknowledge strategic development funding from the University of Sussex. Additional funding from the Aragon Government is also acknowledged (Grupo de Nanosensores y Sistemas Bioanalíticos (N&SB), ref. E25_20R). [...] This work was also partially supported by a UKRI Future Leaders Fellowship (Grant No. MR/T042664/1).

1 figure.-- Talk delivered at the "Designed Assembly of Colloids at Interfaces - Fundamentals to Applications. Online event", organised by the Liquids and Complex Fluids Group, Institute of Physics (Great Britain), 14th-16th June 2021., In biomedical or pharmaceutical applications, surfactants in conventional emulsions can cause tissue irritation or cell damage. In this work, biocompatible nanoparticles of sp3 carbon, called nanodiamond (ND), with a carboxylated surface, were used to prepare mono-sized Pickering emulsions of sunflower oil in water. Emulsification of the oil in acidic ND dispersions was achieved via two different techniques: membrane emulsification and probe sonication. Whereas membrane emulsification fabricated larger (about 30 μm) oil droplets (Figure 1), probe sonication resulted in smaller (sub-μm) droplets and higher stability for a wide range of pH values (acidic to alkaline). The emulsions show high stability against mechanical vibration and offer long-term storage up to one year. Pendant drop tensiometry confirmed that ND particles are adsorbed at the oil/water interface, with a greater decrease in interfacial tension found with increasing ND concentrations in the dispersion. ND coatings become more hydrophilic with increasing pH, according to three-phase contact angle analysis, because of deprotonation of the carboxylic acid groups. Destabilisation of the Pickering emulsion at very high pH was demonstrated in highly alkaline buffers, which is due to the saponification of the vegetable oil and association with cations in solution. This is the first systematic study of carboxylic ND-stabilized Pickering emulsions, and it indicates a very promising prospect for a range of applications.

Talk delivered at the 13th Spanish Conference on Electron Devices, CDE 2021, Sevilla (Spain) 9 June 2021 - 11 June 2021, 171142., This work reports on two-dimensional MoS 2 nanomaterial-based resistive gas sensors and their response to sub-ppm NO 2 concentrations. The sensitive material was prepared by drop-casting MoS 2 nanosheet dispersions on silicon nitride suspended membranes. The sensor response was studied at operating temperatures up to 300 °C. The fabricated sensors provided good responses to NO 2 concentrations as low as 20 ppb at room temperature. The n-type MoS 2 sensing mechanism is here discussed., 10.13039/501100004837-Spanish Ministry of Science and Innovation (Grant Number: PID2019-107697RB-C43)

1 figure.-- Abstract of the talk delivered at the 2021 Spring Meeting of the European Materials Research Society (E-MRS), Virtual Conference, from May 31st to June 3rd, 2021., The performance of transparent silver nanowire (AgNW) electrodes can be improved by using thin coatings of two-dimensional assemblies of amino-terminal oligoglycines (denoted as tectomers), which causes a ~50% sheet resistance decrease for AgNW electrodes with initial resistivities of 100 Ω/sq, while largely retaining the electrodes’ high transparency. Tectomer coatings also remarkably impart enhanced hydrophobicity and protection against AgNW degradation under ambient conditions. Additionally, these coatings are pH-sensitive, and their rich surface chemistry enables opening new perspectives on the fabrication of AgNW electrodes with (bio)sensor functionalities. In this work, we report on the laser patterning of AgNW electrodes biofunctionalized with tectomer coatings. A pulsed, green laser (532nm) was utilized to create non-conductive paths, 12 to 50 μm in width, and the conditions were tuned to avoid the damage of the substrate materials: glass and polyethylene terephthalate (PET) for rigid and flexible electrodes, respectively. The electron transport properties, transparency, and durability of the resulting interdigitated electrodes were characterized, and their potential applications in optoelectronics will be discussed.

Work presented at the International Biodeterioration & Biodegradation Symposium (IBBS18), 6-9 September 2021 | Online conference, The atomically thin 2D materials have unique physicochemical properties useful for sensing applications in chemical, biological and corrosion science.1, 2 The high surface-to-volume ratio of these layered materials facilitates efficient response due to the ultrafast carrier mobility of surface atoms. These surface atoms form physiosorbed bonds with adsorbed analyte through electrostatic interactions that can be envisioned in terms of locally induced strain (%) and charge redistribution (n) compared to its pristine state.3 The non-covalent interaction between the analyte and 2D materials shift the Fermi energy level of the host, useful for the selectivity as it offers unique ‘figureprints’ in the optical spectrum. Here, I will present an overview of a systematic study of surface analysis techniques, in particular, using scanning probe microscopy and Raman spectroscopy to uncover physical strain and doping in different 2D materials of graphene and MoS2 for physio-adsorption of analytes. The present study strengthens the possibility of sensing the interaction between several organic and biomolecules toward different 2D materials which is essential in biological and polymeric systems.

1 figure.-- Talk delivered at the SmallChem 2021 International online conference (17th-18th february 2021)., Amino-terminated oligoglycines non-covalently self-assemble, through cooperative hydrogen bonding formation, into biocompatible rigid 2D nanostructures called tectomers, either in solution or in surfacepromoted processes. Tectomers effectively coat carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and strongly interact with graphene oxide (GO). Electrostatic interactions and hydrogen bonding formation accounts for the strong interfacial interaction of tectomers with MWCNTCOOH and GO, respectively. The resulting composites were characterized by electron- and atomic force microscopies, UV-vis and X-ray photoelectron (XPS) spectroscopies and contact angle measurements. Because of this high affinity of tectomers to GO, tectomers efficiently coat wet-spun GO fibers (Fig. 1). We also show that, due to their versatile surface chemistry, tectomers act as supramolecular peptidic adhesives for the immobilization of a variety of carbon nanomaterials, nanoparticles, molecules and drugs on the GO fiber surface therefore allowing GO fiber functionalization. The resulting ultrathin coatings exhibit remarkable water-resistant properties. This tectomer-based “double-sided sticky tape” fiber functionalization strategy can be extended to other fibers, fabrics and substrates, making it very attractive for technological and smart textile applications

6 figures, 4 tables. This work is a review on HPTLC contribution to lipid analysis in complex matrices, in the period from 2010 to now, lapse of time where hyphenation with other techniques, especially Mass Spectrometry, has experienced an important growth. Scanning densitometry (SD)-UV/FL of separated lipids, as the core of detection and centerpiece for hyphenation, and its coupling with MS using soft ionization techniques (ESI, APCI, MALDI, DESI and others), are the central axis of this work. The occasional intercalation in this coupling of an on-plate biological assay for effect-direct analysis (EDA) of lipids, as well as the combination of SD with radio-densitometry (RD) using isotopically labeled-lipids are also covered topics. The described techniques make possible to develop strategies for obtaining qualitative and different levels of quantitative information, including untargeted lipids species. HPTLC of lipids has been used for: comparative purposes; fingerprinting; semi-quantitative determination, identification of species; or quantitative determination of a given individual lipid. Goals in molecular biology and biochemistry-related samples have been: preparative isolations; control of purity; verification of metabolic products; on-plate biological assays; profiles in cells; analysis of products from the cellular metabolism; measurement of enzymatic activities; monitoring lipid transport across membranes or at biological interfaces; or monitoring lipid dynamics. One of us (J.G.) thanks to Spanish Plan Nacional I + D+i (CTQ2016-76846R project). This work was supported by DGA-ESF [project 25_20R].

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).

Work presented at the nano Portugal 2020 Online Conference (nanoPT2020), Nanoscience and Nanotechnology International Conference, 23th - 24th september 2020., Amino-terminated oligoglycines non-covalently self-assemble, through cooperative hydrogen bonding formation, into biocompatible rigid 2D nanostructures called tectomers. Tectomers effectively coat carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and strongly interact with graphene oxide (GO). Electrostatic interactions and hydrogen bonding formation accounts for the strong interfacial interaction of tectomers with MWCNT-COOH and GO, respectively. Because of the high affinity of tectomers to GO, tectomers have been used to coat wet-spun GO fibers. We here show that, due to their versatile surface chemistry, tectomers act as supramolecular adhesives for nanomaterial and molecule immobilization on the GO fiber surface. Tectomer-coated GO fibers can then be subsequently decorated with a variety of carbon nanomaterials (carbon nanotubes, carbon nanohorns, carbon nanocones, and highly fluorescent nanodiamonds), metal (gold, platinum, iron) nanoparticles, acrylate-based polymer nanoparticles, fluorophores and drugs. The resulting ultrathin coatings exhibit remarkable water resistant properties. We show that this tectomer-based “double-sided sticky tape” fiber functionalization strategy can be extended to other fibers and fabrics, such as polyurethane/PEDOT:PSS, poly(methyl methacrylate) and polyester, making it very attractive for a variety of technological and smart textile applications.

3 figures, 1 table.-- Poster presented at the nano Portugal 2020 Online Conference (nanoPT2020), Nanoscience and Nanotechnology International Conference, 23th 24th september 2020., Due to their large surface area, high cellular internalization and preferential tumor accumulation, carbon nanomaterials have attracted much attention in biomedicine to be used as drug nanocarriers to transport chemotherapeutic [1-3]. Furthermore, these systems could be used for formulation of hydrophobic molecules which lack of suitable physicochemical characteristics required for development of stable pharmaceutical dosage form. Camptothecin (CPT) is a more potent anticancer agent than other well-known anticancer drugs such as doxorubicin (DOX). However, CPT practical use is greatly hampered due to its low solubility in biological media, so developing new drug delivery nanocarriers for CPT would be of high interest [4]. In this work, the potential of carbon nanotubes (CNT), graphene oxide (GO), reduced graphene oxide (RGO) and carbon nanodiamonds (ND) in the field of drug delivery as nanocarriers of CPT was compared. In vitro studies were performed on human epithelial colorectal adenocarcinoma (Caco-2) cells. The highest improvement in CPT anticancer activity was obtained for nanocarriers that are able to establish strong π-π interactions with CPT [5]., Diputación General de Aragón (projects E25_20R and B16-17R); CIBEROBN (Grant CB06/03/1012); European Grant Interreg/SUDOE (Redvalue, SOE1/PI/E0123)

2 Figures.-- Talk delivered in IX NYNA 2019 International Congress on Analytical Nanoscience and Nanotechnology in Zaragoza, Spain, 2-4 July 2019., Biogenic amines (BAs) are low molecular weight nitrogenous compounds that mainly result from the decarboxylation of free amino acids in food by microorganisms. At high concentrations, they cannot be metabolized by the body and pass to the blood stream, triggering intoxication processes.Because of the growing concern in food security, the quality control in food requires the development of fast and economic methods for the detection of BAs. Most methods are based on HPLC-MS techniques, and usually require a previous derivatization, so that they are expensive and tedious.The purpose of this work is the development of an optical sensor for the detection of BAs, as shown in Figure 1, where the enzymes amine oxidase (AO) and peroxidase (HRP), and a dye (ABTS) are immobilized on mica supports, so that the dye turns blue in presence of BAs., This work has been carried out under the Project CTQ2016-76846R (MINECO) and the aid to the research groups DGA-FEDER (E25_17R)

16 Figuras.-- Información suplementaria disponible en línea en la página web del editor.-- © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/, Amino-terminated oligoglycine two-dimensional (2D) peptide self-assemblies (known as tectomers) have a versatile surface chemistry that allows them to interact with a variety of nanomaterials and to actas supramolecular adhesives for surface functionalization. Here, we have exploited the strong hydrogen-bond based interaction between tectomers and graphene oxide (GO) to functionalize GO fiber surfaces with different carbon nanomaterials (carbon nanotubes, carbon nanohorns, carbon nanocones, and highly fluorescent nanodiamonds), metal (gold, platinum, iron) nanoparticles, acrylate-based polymernanoparticles, fluorophores and drugs. The resulting ultrathin coatings exhibit remarkable water resis-tant properties. This tectomer-mediated fiber decoration strategy allows coating functionalities to be tailored by choosing the appropriate nanomaterials or other molecules. We show that this strategy can be extended to other fibers and fabrics, such as polyurethane/PEDOT:PSS, poly(methyl methacrylate) and polyester, making it very attractive for a variety of technological and smart textile applications., Authors thank the Fundación Domingo Martínez (Ayudas a la Investigación 2013) and Diputación General de Aragón (Grupo de Nanosensores y Sistemas Bioanalíticos (N&SB), ref. E25_17R) for research funding. MT would like to acknowledge University of Sussex strategic development fund. JMR acknowledges funding from the Australian Research Council (DP170102859).

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.

9 Figuras.-- Información complementaria disponible en línea en la página web del editor.-- This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in ACS Applied Nano Materials 1,8, 3903-3912 (2018), copyright © American Chemical Society after peer review. To access the final edited and published work see http://dx.doi.org/10.1021/acsanm.8b00689, Here, we describe the unusual self-assembly of amine-terminated oligoglycine peptides into extended two-dimensional sheets in the presence of silver nanowires. The resulting tectomer sheets are shown to have a strong affinity for the nanowires through a charge-transfer interaction as evidenced by X-ray photoelectron spectroscopy. We show that extended assemblies of metal–peptide hybrids offer additional augmentative functionalities; for instance, the tectomer sheets are hydrophobic in nature and act as a protective layer preventing oxidation and degradation of the nanowires when exposed to atmospheric conditions. Moreover, for silver nanowire percolating networks the presence of the peptide markedly increases the overall electrical conductivity through mechanical squeezing of wire–wire junctions in the network. The peptide–metal interface can be controlled by pH stimulus thus potentially offering new directions where silver nanowire assemblies are used for transparent electrodes ranging from antimicrobial coatings to biosensors., This work was supported by Grant EP/K031562 from the Engineering and Physical Sciences Research Council (EPSRC), ENE2013-48816-C5-5-R project (Plan Nacional de I+D+I, from Spanish Ministerio de Economía y Competitividad MINECO), and H2020-MSCA-ITN-2014 Enabling Excellence project.

2 figures.-- Poster presented at the 1st International Caparica Conference on Chromagenic and Emissive Materials, IC3EM 2014, 8th-10th September, 2014, Caparica (Portugal)., Low-toxic coralyne, a cationic benzo[c]phenanthridine type alkaloid (Fig. 1), has received extensive attention because of its DNA- and RNA-targeting properties, and antimicrobial, anticancer activity, more pronounced compared to other protoberberine alkaloids [1-3]. In a previous work we showed that the fluorescence intensity alteration of coralyne-impregnated silica gel plates allows the sensitive quantitative detection of a wide number of analytes by high-performance thin layer chromatographic techniques [4]. It has been shown that coralyne cation undergoes self-aggregation in aqueous solutions by stacking interactions, even at low dye concentration, being the dimer less fluorescent than the monomer [5, 6]. In this work we have studied the influence of temperature in dimer formation. Due to its large flat aromatic structure, coralyne also has a high tendency to penetration into organized assemblies in solution with hydrophobic core such as micelles or liposomes, and we present here a fluorescence study of coralyne in different microheterogeneous media. Fluorescence emission increases when coralyne probe is situated in apolar microenvironments which prevent non-radiative desexcitation pahtways (Fig. 2)., Authors thank the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER (UE) (Plan Nacional de I+D+I, project CTQ2012-035535) and to DGA-ESF, for financial support. C.J. thanks CSIC and ESF for a JAE-doc grant. E. R. thanks to the Ministerio de Ciencia e Innovación (MICINN) for a grant.

14 slides.-- Slideshow of the talk delivered in the International Symposium for High-Performance Thin-Layer Chromatography, HPTLC 2008, 11th-13th, June 2008, Helsinki (Finland).

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.