Two-dimensional self-assembly and electrical properties of the donor-acceptor tetrathiafulvalene-polychlorotriphenylmethyl radical on graphite substrates

The electron donor-acceptor tetrathiafulvalene-polychlorotriphenylmethyl (PTM) radical dyad, which shows a strong interplay between intra- and intermolecular charge transfer processes in solution, has been deposited by drop-casting on highly oriented pyrolytic graphite substrates, and its self-assembled structure has been investigated. Conducting atomic force microscopy revealed that the presence of a PTM radical in the molecules enhances the electrical conduction by almost two orders of magnitude and that this enhancement occurs in spite of the poor molecular orientation control achieved with drop-casting. Moreover, the study also reveals that the presence of a tetrathiafulvalene subunit in the deposited molecules can result in slightly asymmetric I-V curves

Exploring the impact of the recombinant Escherichia coli strain on defensins antimicrobial activity: BL21 versus Origami strain

The growing emergence of microorganisms resistant to antibiotics has prompted the development of alternative antimicrobial therapies. Among them, the antimicrobial peptides produced by innate immunity, which are also known as host defense peptides (HDPs), hold great potential. They have been shown to exert activity against both Gram-positive and Gram-negative bacteria, including those resistant to antibiotics. These HDPs are classified into three categories: defensins, cathelicidins, and histatins. Traditionally, HDPs have been chemically synthesized, but this strategy often limits their application due to the high associated production costs. Alternatively, some HDPs have been recombinantly produced, but little is known about the impact of the bacterial strain in the recombinant product. This work aimed to assess the influence of the Escherichia coli strain used as cell factory to determine the activity and stability of recombinant defensins, which have 3 disulfide bonds. For that, an α-defensin [human α-defensin 5 (HD5)] and a β-defensin [bovine lingual antimicrobial peptide (LAP)] were produced in two recombinant backgrounds. The first one was an E. coli BL21 strain, which has a reducing cytoplasm, whereas the second was an E. coli Origami B, that is a strain with a more oxidizing cytoplasm. The results showed that both HD5 and LAP, fused to Green Fluorescent Protein (GFP), were successfully produced in both BL21 and Origami B strains. However, differences were observed in the HDP production yield and bactericidal activity, especially for the HD5-based protein. The HD5 protein fused to GFP was not only produced at higher yields in the E. coli BL21 strain, but it also showed a higher quality and stability than that produced in the Origami B strain. Hence, this data showed that the strain had a clear impact on both HDPs quantity and quality.info:eu-repo/semantics/publishedVersio

Las dificultades del aprendizaje autónomo en un contexto de ABP

Objetivos: Identificar las dificultades que experimentan los estudiantes en un proceso de aprendizaje autodirigido. Elaborar un inventario y una clasificación de las dificultades identificadas. Diagnosticar las causas de las dificultades y apuntar vías o posibilidades de superación. Evaluar el impacto de las dificultades en el producto final. Datos del análisis empírico: Participan en el estudio un total de 80 estudiantes de los dos últimos cursos de la licenciatura de Derecho. Curso académico 2006-2007. Facultad de Derecho de la Universidad de Barcelona. Metodología de trabajo: Estudio etnográfico. Resultados: Para los estudiantes que no tienen experiencia previa en ABP la mayor dificultad es la desorientación y la angustia que sufren ante la ausencia de un temario. Existen dificultades de interacción con los tutores derivadas de la divergente concepción e inteligencia de significados. Finalmente, se han detectado dificultades derivadas de la influencia del entorno (hábitos personales) y otras conectadas con los estilos de aprendizaje de cada estudiante.Objectives: To identify the difficulties that the students have in a process of selflearning. To elaborate an inventory of the identified difficulties. To diagnose the causes of the difficulties and to point routes or possibilities of overcoming. To evaluate the impact of the difficulties in the end item. Empiric analysis data: 80 students of the two last years in law studies. Academic year 2006-2007. Faculty of Law of the University of Barcelona. Methodology: Ethnografic study. Results: For students who do not have previous experience in ABP the greater difficulty is the disorientation and the anguish that suffer because of the absence of an agenda. They exist difficulties of interaction with the tutors derived from the divergent conception and intelligence of meaning. Finally, difficulties derived from the influence of the surroundings (personal habits) and connected others with the learning styles of each student have been detected

Three-dimensional cell culture of chimeric antigen receptor T cells originated from peripheral blood mononuclear cells towards cellular therapies

3D cell culture; CAR T cells; Adoptive cell therapyCultiu cel·lular 3D; Cèl·lules T CAR; Teràpia cel·lular adoptivaCultivo celular 3D; Células T CAR; Terapia celular adoptivaBackground aims With the objective of improving the ex vivo production of therapeutic chimeric antigen receptor (CAR) T cells, we explored the addition of three-dimensional (3D) polystyrene scaffolds to standard suspension cell cultures. Methods We aimed to mimic the structural support given by the lymph nodes during in vivo lymphocyte expansion. Results We observed an increase in cell proliferation compared with standard suspension systems as well as an enhanced cytotoxicity toward cancer cells. Moreover, we directly obtained the CAR T cells from peripheral blood mononuclear cells, thus minimizing the ex vivo manipulation of the therapeutic cells and opening the way to synergies among different cell populations. Conclusions We propose the use of commercially available 3D polystyrene systems to improve the current immune cell cultures and resulting cell products for emerging cellular (immuno)therapies.This research was funded by Instituto de Salud Carlos III through Consorcio Centro de Investigación Biomédica en Red (CIBER) with the projects “Alycia” (Nr. BBN18PI01) and “Gels4ACT” (Nr. BBN20PIV02). The authors are also grateful for the financial support received from the Spanish Ministry of Science and Innovation (PID2020-115296RA-I00, PID2019-105622RBI00 and the “Ramón y Cajal” program [RYC-2017-22614]). The work was supported as well by the Max Planck Society through the Max Planck Partner Group “Dynamic Biomimetics for Cancer Immunotherapy” in collaboration with the Max Planck for Medical Research (Heidelberg, Germany). This research was also supported by the European Union's Horizon 2020 research and innovation programme H2020-MSCA-COFUND-2016 (DOC-FAM, grant agreement Nr. 754397). The authors acknowledge financial support from the Spanish Ministry of Science and Innovation through the “Severo Ochoa” Programme for Centres of Excellence in R&D (CEX2019-000917-S)

CCL21-loaded 3D hydrogels for T cell expansion and differentiation

Recent achievements in the field of immunotherapy, such as the development of engineered T cells used in adoptive cell therapy, are introducing more efficient strategies to combat cancer. Nevertheless, there are still many limitations. For example, these T cells are challenging to manufacture, manipulate, and control. Specifically, there are limitations in producing the large amounts of therapeutic T cells needed for these therapies in a short period of time and in an economically viable manner. In this study, three-dimensional (3D) poly(ethylene) glycol (PEG) hydrogels covalently combined with low molecular weight heparin are engineered to resemble the lymph nodes, where T cells reproduce. In these hydrogels, PEG provides the needed structural and mechanical properties, whereas heparin is used as an anchor for the cytokine CCL21, which is present in the lymph nodes, and can affect cell migration and proliferation. The 3D structure of the hydrogel in combination with its loading capacity result in an increased primary human CD4+ T cell proliferation compared to the state-of-the-art expansion systems consisting of artificial antigen presenting cells. Thus, we present a new tool for adoptive cell therapy to help achieving the large numbers of cells required for therapy of selected phenotypes targeted against cancer cells, by mimicking the lymph nodes.info:eu-repo/semantics/publishedVersio

Ratiometric Nanothermometer Based on a Radical Excimer for In Vivo Sensing

Ratiometric fluorescent nanothermometers with near-infrared emission play an important role in in vivo sensing since they can be used as intracellular thermal sensing probes with high spatial resolution and high sensitivity, to investigate cellular functions of interest in diagnosis and therapy, where current approaches are not effective. Herein, the temperature-dependent fluorescence of organic nanoparticles is designed, synthesized, and studied based on the dual emission, generated by monomer and excimer species, of the tris(2,4,6-trichlorophenyl)methyl radical (TTM) doping organic nanoparticles (TTMd-ONPs), made of optically neutral tris(2,4,6-trichlorophenyl)methane (TTM-αH), acting as a matrix. The excimer emission intensity of TTMd-ONPs decreases with increasing temperatures whereas the monomer emission is almost independent and can be used as an internal reference. TTMd-ONPs show a great temperature sensitivity (3.4% K-1 at 328 K) and a wide temperature response at ambient conditions with excellent reversibility and high colloidal stability. In addition, TTMd-ONPs are not cytotoxic and their ratiometric outputs are unaffected by changes in the environment. Individual TTMd-ONPs are able to sense temperature changes at the nano-microscale. In vivo thermometry experiments in Caenorhabditis elegans (C. elegans) worms show that TTMd-ONPs can locally monitor internal body temperature changes with spatio-temporal resolution and high sensitivity, offering multiple applications in the biological nanothermometry field.© 2023 The Authors. Small published by Wiley-VCH GmbH

Antibiofilm surfaces based on the immobilization of a novel recombinant antimicrobial multidomain protein using self-assembled monolayers

The constant increase of microorganisms resistant to antibiotics has been classified as a global health emergency, which is especially challenging when biofilms are formed. Herein, novel biofunctionalized gold surfaces with the antimicrobial multidomain recombinant protein JAMF1, both in the soluble form and nanostructured as nanoparticles, were developed. The interaction between His-tag termination of the protein and a nitriloacetic acid–Ni complex formed on mixed self-assembled monolayers (mixed SAMs) was exploited. The obtained antibiofilm surfaces based on the immobilization of the novel JAMF1 protein using self-assembled monolayers were characterized using a multi-technique approach including: cyclic voltammetry, X-ray photoelectron spectroscopy, atomic force microscopy and fluorescence, proving that the modification and immobilization of JAMF1 were successfully done. The antibiofilm activity against Escherichia coli and carbapenem-resistant Klebsiella pneumoniae showed that the immobilized antimicrobial proteins were able to reduce biofilm formation of both microorganisms. This strategy opens up new possibilities for controlled biomolecule immobilization for fundamental biological studies and biotechnological applications, at the interface of materials science and molecular biology.info:eu-repo/semantics/publishedVersio

A Novel Generation of Tailored Antimicrobial Drugs Based on Recombinant Multidomain Proteins

Antibiotic resistance has exponentially increased during the last years. It is necessary to develop new antimicrobial drugs to prevent and treat infectious diseases caused by multidrug- or extensively-drug resistant (MDR/XDR)-bacteria. Host Defense Peptides (HDPs) have a versatile role, acting as antimicrobial peptides and regulators of several innate immunity functions. The results shown by previous studies using synthetic HDPs are only the tip of the iceberg, since the synergistic potential of HDPs and their production as recombinant proteins are fields practically unexplored. The present study aims to move a step forward through the development of a new generation of tailored antimicrobials, using a rational design of recombinant multidomain proteins based on HDPs. This strategy is based on a two-phase process, starting with the construction of the first generation molecules using single HDPs and further selecting those HDPs with higher bactericidal efficiencies to be combined in the second generation of broad-spectrum antimicrobials. As a proof of concept, we have designed three new antimicrobials, named D5L37βD3, D5L37D5L37 and D5LAL37βD3. After an in-depth exploration, we found D5L37D5L37 to be the most promising one, since it was equally effective against four relevant pathogens in healthcare-associated infections, such as methicillin-susceptible (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis (MRSE) and MDR Pseudomonas aeruginosa, being MRSA, MRSE and P. aeruginosa MDR strains. The low MIC values and versatile activity against planktonic and biofilm forms reinforce the use of this platform to isolate and produce unlimited HDP combinations as new antimicrobial drugs by effective means.info:eu-repo/semantics/publishedVersio

Las dificultades del aprendizaje autónomo en un contexto de ABP

Objectives: To identify the difficulties that the students have in a process of selflearning. To elaborate an inventory of the identified difficulties. To diagnose the causes of the difficulties and to point routes or possibilities of overcoming. To evaluate the impact of the difficulties in the end item. Empiric analysis data: 80 students of the two last years in law studies. Academic year 2006-2007. Faculty of Law of the University of Barcelona. Methodology: Ethnografic study. Results: For students who do not have previous experience in ABP the greater difficulty is the disorientation and the anguish that suffer because of the absence of an agenda. They exist difficulties of interaction with the tutors derived from the divergent conception and intelligence of meaning. Finally, difficulties derived from the influence of the surroundings (personal habits) and connected others with the learning styles of each student have been detected.Objetivos: Identificar las dificultades que experimentan los estudiantes en un proceso de aprendizaje autodirigido. Elaborar un inventario y una clasificación de las dificultades identificadas. Diagnosticar las causas de las dificultades y apuntar vías o posibilidades de superación. Evaluar el impacto de las dificultades en el producto final. Datos del análisis empírico: Participan en el estudio un total de 80 estudiantes de los dos últimos cursos de la licenciatura de Derecho. Curso académico 2006-2007. Facultad de Derecho de la Universidad de Barcelona. Metodología de trabajo: Estudio etnográfico. Resultados: Para los estudiantes que no tienen experiencia previa en ABP la mayor dificultad es la desorientación y la angustia que sufren ante la ausencia de un temario. Existen dificultades de interacción con los tutores derivadas de la divergente concepción e inteligencia de significados. Finalmente, se han detectado dificultades derivadas de la influencia del entorno (hábitos personales) y otras conectadas con los estilos de aprendizaje de cada estudiante