Polímeros para la biofuncionalización de nanopartículas de oro

En los últimos años, las nanopartículas de oro están siendo utilizadas como vehículos de fármacos para tratar enfermedades como el cáncer. Sin embargo, cuando las nanopartículas se introducen en el organismo, quedan cubiertas por una capa de biomoléculas (corona proteica), lo que disminuye el tiempo de circulación y la eficacia de las nanopartículas. Este trabajo tiene como objetivo la síntesis de nanopartículas de oro (AuNPs) cuyo recubrimiento cambie de signo con el pH. Este cambio de signo reduciría o eliminaría la corona de proteínas. En primer lugar, se ha llevado a cabo la síntesis de tres polímeros polietilenglicol (PEG) diferentes. Todos ellos tienen en común un extremo con un grupo ditiolano, encargado de la unión con la nanopartícula, y difieren en el otro extremo de la cadena. Todos los productos se han caracterizado mediante resonancia magnética nuclear (RMN), espectroscopía infrarroja (FT-IR) y espectrometría de masas (EM). En segundo lugar, se han sintetizado nanoesferas de aproximadamente 14 nm de diámetro. Las nanoesferas se han obtenido recubiertas con un ligando citrato, que posteriormente se ha sustituido mediante una reacción de intercambio de ligando por cada uno de los polímeros preparados anteriormente. Para la obtención del grupo dependiente de pH se han seguido dos estrategias. Una de ellas consiste en la formación sobre la misma nanopartícula del grupo amida dependiente de pH, mientras que en la otra estrategia la amida se ha formado antes del intercambio de ligando. Las nanopartículas se han caracterizado mediante microscopía electrónica de transmisión (MET), electroforesis en gel de agarosa, espectroscopía de absorbancia ultravioleta-visible (UV-Vis) y análisis termogravimétrico (TGA). Por último, el comportamiento de las nanopartículas a diferentes pH se ha estudiado mediante dispersión dinámica de la luz (DLS) y medidas de potencial Z

Polyoxometalate–peptide hybrid materials: from structure–property relationships to applications

Organo-functionalisation of polyoxometalates (POMs) represents an effective approach to obtain diverse arrays of functional structures and materials, where the introduction of organic moieties into the POM molecules can dramatically change their surface chemistry, charge, polarity, and redox properties. The synergistic combination of POMs and peptides, which perform a myriad of essential roles within cellular biochemistry, including protection and transport in living organisms, leads to functional hybrid materials with unique properties. In this Perspective article, we present the principal synthetic routes to prepare and characterise POM–peptide hybrids, together with a comprehensive description of how their properties – such as redox chemistry, stereochemistry and supramolecular self-assembly – give rise to materials with relevant catalytic, adhesive, and biomedical applications. By presenting the state-of-the-art of the POM–peptide field, we show specifically how emerging chemical approaches can be harnessed to develop tailored POM–peptide materials with synergistic properties for applications in a variety of disciplines

Surfactant-free synthesis and scalable purification of triangular gold nanoprisms with low non-specific cellular uptake

Gold nanoprisms possess remarkable optical properties that make them useful for medical biotechnology applications such as diagnosis and photothermal therapy. However, shape-selective synthesis of gold nanoprisms is not trivial and typically requires either toxic surfactants or time-consuming purification protocols, which can limit their applicability. Here, we show how triangular gold nanoprisms of different sizes can be purified by precipitation using the non-toxic glutathione ligand, thereby removing the need for toxic surfactants and bottleneck purification techniques. The protocol is amenable for direct scaling up as no instrumentation is required in the critical purification step. The new purification method provides a two-fold increased yield in gold nanoprisms compared to electrophoretic filtration, while providing nanoprisms of similar localized surface plasmon resonance wavelength. Crucially, the gold nanoprisms isolated using this methodology show fewer non-specific interactions with cells and lower cellular internalization, which paves the way for a higher selectivity in therapeutic applications

Tuning of Mechanical Properties in Photopolymerizable Gelatin-Based Hydrogels for <i>In Vitro</i> Cell Culture Systems

The mechanical microenvironment plays a crucial role in the evolution of colorectal cancer, a complex disease characterized by heterogeneous tumors with varying elasticity. Toward setting up distinct scenarios, herein, we describe the preparation and characterization of gelatin methacrylamide (GelMA)-based hydrogels via two different mechanisms: free-radical photopolymerization and photo-induced thiol-ene reaction. A precise stiffness modulation of covalently crosslinked scaffolds was achieved through the application of well-defined irradiation times while keeping the intensity constant. Besides, the incorporation of thiol chemistry strongly increased stiffness with low to moderate curing times. This wide range of finely tuned mechanical properties successfully covered from healthy tissue to colorectal cancer stages. Hydrogels prepared in phosphate-buffered saline or Dulbecco’s modified Eagle’s medium resulted in different mechanical and swelling properties, although a similar trend was observed for both conditions: thiol-ene systems exhibited higher stiffness and, at the same time, higher swelling capacity than free-radical photopolymerized networks. In terms of biological behavior, three of the substrates showed good cell proliferation rates according to the formation of a confluent monolayer of Caco-2 cells after 14 days of cell culture. Likewise, a characteristic apical-basal polarization of cells was observed for these three hydrogels. These results demonstrate the versatility of the presented platform of biomimetic materials as in vitro cell culture scaffolds

The Mechanical and Biological Performance of Photopolymerized Gelatin-Based Hydrogels as a Function of the Reaction Media

From the first experiments with biomaterials to mimic tissue properties, the mechanical and biochemical characterization has evolved extensively. Several properties can be described, however, what should be essential is to conduct a proper and physiologically relevant characterization. Herein, the influence of the reaction media (RM) and swelling media (SM)–phosphate buffered saline (PBS) and Dulbecco's modified Eagle's medium (DMEM) with two different glucose concentrations–is described in gelatin methacrylamide (GelMA) hydrogel mechanics and in the biological behavior of two tumoral cell lines (Caco‐2 and HCT‐116). All scaffolds are UV‐photocrosslinked under identical conditions and evaluated for mass swelling ratio and stiffness. The results indicate that stiffness is highly susceptible to the RM, but not to the SM. Additionally, PBS‐prepared hydrogels exhibited a higher photopolymerization degree according to high resolution magic‐angle spinning (HR‐MAS) NMR. These findings correlate with the biological response of Caco‐2 and HCT‐116 cells seeded on the substrates, which demonstrated flatter morphologies on stiffer hydrogels. Overall, cell viability and proliferation are excellent for both cell lines, and Caco‐2 cells displayed a characteristic apical‐basal polarization based on F‐actin/Nuclei fluorescence images. These characterization experiments highlight the importance of conducting mechanical testing of biomaterials in the same medium as cell culture

Nuevos polímeros anfifílicos para la transferencia de nanopartículas a fase acuosa

Las nanopartículas inorgánicas tienen una gran variedad de aplicaciones en distintos ámbitos entre los cuales se encuentra la biotecnología. Para estabilizar estas nanopartículas, se han usado distintos tipos de moléculas entre las cuales se encuentran los polímeros anfifílicos que les otorgan la capacidad de pasar de medio orgánico (hexano) a medio acuoso. Hasta el momento, el polímero utilizado es el poli(anhídrido maleico-alt-1-octadeceno) (PMAO) a partir del cual, en este trabajo, se plantea la síntesis de distintos polímeros anfifílicos: con la mitad de cargas negativas (polímero 1) que el polímero original o con cargas positivas (polímero 2). Una vez obtenidos los polímeros deseados y caracterizados por RMN e IR se han utilizado para transferir nanopartículas magnéticas de hexano a agua. El polímero 2 no estabiliza adecuadamente las nanopartículas en medio acuoso. Sin embargo el polímero 1, ha presentado un gran potencial para este fin. Las nanopartículas recubiertas por el polímero 1 son monodispersas y estables en agua y se han caracterizado por TEM, DLS, TGA y potencial Z. Por último se ha realizado su funcionalización con un fluoróforo y glucosa. Inorganic nanoparticles have been widely investigated due to their variety of applications in diverse fields including biotechnology. Different kinds of molecules such as polymers, have been used to stabilize nanoparticles. Amphiphilic polymers give them the ability to move from organic medium (hexane) to aqueous medium. Until now, poly(maleic anhydride-alt-1-octadecene) (PMAO) has been the polymer of choice. In this essay the synthesis of two polymers is raised from PMAO. The polymer 1 has half of charges than the original one and the polymer 2 has positive charges. Once obtained, the desired polymers were characterized by RMN and IR and they were used to transfer nanoparticles from hexane to water. The polymer 2 doesn't stabilize adequately nanoparticles in aqueous medium. On the other hand, the polymer 1 has great potential for this purpose. Nanoparticles coated with polymer 1 are monodisperse and stable in aqueous medium and they have been characterized by TEM, DLS, TGA and Z Potential. Finally the functionalization with glucose and a fluorophore has been performed

Subcellular localization and therapeutic efficacy of polymeric micellar nanoparticles encapsulating bedaquiline for tuberculosis treatment in zebrafish

The combination drug regimens that have long been used to treat tuberculosis (TB), caused by Mycobacterium tuberculosis, are fraught with problems such as frequent administration, long duration of treatment, and harsh adverse effects, leading to the emergence of multidrug resistance. Moreover, there is no effective preventive vaccine against TB infection. In this context, nanoparticles (NPs) have emerged as a potential alternative method for drug delivery. Encapsulating antibiotics in biodegradable NPs has been shown to provide effective therapy and reduced toxicity against M. tuberculosis in different mammalian models, when compared to conventional free drug administration. Here, we evaluate the localization, therapeutic efficacy and toxic effects of polymeric micellar NPs encapsulating a promising but highly hydrophobic and toxic antitubercular drug bedaquiline (BQ) in zebrafish embryos infected with Mycobacterium marinum. Our study shows that the NP formulation of BQ improves survival and reduces bacterial burden in the infected embryos after treatment when compared to its free form. The intravenously injected BQ NPs have short circulation times due to their rapid and efficient uptake into the endothelial cells, as observed by correlative light and electron microscopy (CLEM)

Hybrid antimicrobial films containing a polyoxometalate-ionic liquid

The increasing resistance of pathogenic microorganisms against common treatments requires innovative concepts to prevent infection and avoid long-term microbe viability on commonly used surfaces. Here, we report the preparation of a hybrid antimicrobial material based on the combination of microbiocidal polyoxometalate-ionic liquids (POM-ILs) and a biocompatible polymeric support, which enables the development of surface coatings that prevent microbial adhesion. The composite material is based on an antibacterial and antifungal room-temperature POM-IL composed of guanidinium cations (N,N,N′,N′-tetramethyl-N″, N″-dioctylguanidinum) combined with lacunary Keggin-type polyoxotungstate anions, [α-SiW11O39]8–. Integration of the antimicrobial POM-IL into the biocompatible, flexible, and stable polymer poly(methyl methacrylate) (PMMA) results in processable films, which are suitable as surface coatings or packaging materials to limit the proliferation and spread of pathogenic microorganisms (e.g., on public transport and hospital surfaces, or in ready-to-eat-food packaging).This research was supported by Deutscher Akademischer Austauschdienst DAAD (A.G.E.); Ministerio de Ciencia Innovación y Universidades (Spain) Proyectos I + D + I, PID2019-109333RB-I00 (S.G.M & R.M.-R.); CSIC i-Link + 2019 project LINK20270 (S.G.M & R.M.-R.); European Union’s Horizon 2020 research and innovation program (Marie Skłodowska-Curie grant agreement no. 845427) (E.A.B. and S.G.M); Programa Operativo Aragón de Fondo Social Europeo 2014–2020 (I.F.C.); Agencia Nacional de Promoción Científica y Tecnológica, Argentina (National Agency for Scientific and Technological Promotion, ANPCYT): PICT 2017-3767 (M.B.) and PICT 2017-0340 (M.J.C); the Consejo Nacional de Investigaciones Científicas y Técnicas (National Scientific and Technical Research Council); and the Universidad Nacional del Litoral, CAI + D 50620190100020LI (M.J.C) and Gobierno de Aragón (Project LMP49-18).Peer reviewe

Funcionalización de hidrogeles para aplicaciones biomédicas

Resumen del póster presentado a la 8ª Jornada de Jóvenes Investigadores (Química y Física) de Aragón, celebrada en Zaragoza el dia 22 de noviembre de 2018.Peer Reviewe

Nanotechnology in personalized medicine: A promising tool for Alzheimer's disease treatment

[Background]: Alzheimer’s disease (AD) is a public health priority all over the world. The difficulty of fighting the disease consists mostly in the complexity of symptoms and causes, in the still poor knowledge of its mechanisms and in the existence of a latent, asymptomatic, preclinical stage. Although many drugs are continuously screened in clinical studies for the treatment of Alzheimer’s disease, the unexpected lack of patient response and sometimes the important adverse effects make it a potential field of application for personalized medicine.[Objective]: This perspective review proposes nanotechnology as a valuable tool for the application of personalized medicine to AD.[Methods]: The aim of personalized medicine is the development of more patient-precise treatments based mostly on the knowledge of individual genetics as well as of disease progress, and of pharmacokinetics and metabolic response to available drugs. The optimization of new and more sensitive detection techniques is an important tool for obtaining the pool of data needed for prediction and understanding of patient response.[Results]: Research in bionanosensors is already providing examples with high sensitivity for core and new biomarkers for AD. In therapy the functionalization of nanoparticle surface can add specificity for biological recognition or for improving the bioavailability. This would allow the administration of lower doses with less adverse effects due to the local targeting.[Conclusion]: Taking into account the promising characteristics of nanoparticles as excellent candidate tools for precision medicine development, the establishment of better standard methods for safety assessment and production scale up would be desirable for the nanomaterial fruitful employment.Financial support by “Fundación BBVA”, “Diputación General de Aragón” (E93), Fondo Social Europeo (FSE; Gobierno de Aragón) and Ministerio de la Economía y Competitividad del Gobierno de España for the public funding of Proyectos I+D+i - Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad (projects n. SAF2014-54763-C2-2-R and CTQ2015-66869-P) is acknowledged by all the authors. R.M.-R. thanks the Spanish Ministerio de Economía y Competitividad for his contract under the “Ramón y Cajal” subprogram (RYC-2013-12570).Peer reviewe