Showing papers by "Daniel Maspoch published in 2015"
TL;DR: Etching tests on these ZIFs reveal that etching occurs preferentially in the crystallographic directions richer in metal-ligand bonds; that, along these directions, the etching rate tends to be faster on the crystal surfaces of higher dimensionality; and that the etch can be modulated by adjusting the pH of the etchant solution.
Abstract: Controlling the shape of metal-organic framework (MOF) crystals is important for understanding their crystallization and useful for myriad applications. However, despite the many advances in shaping of inorganic nanoparticles, post-synthetic shape control of MOFs and, in general, molecular crystals remains embryonic. Herein, we report using a simple wet-chemistry process at room temperature to control the anisotropic etching of colloidal ZIF-8 and ZIF-67 crystals. Our work enables uniform reshaping of these porous materials into unprecedented morphologies, including cubic and tetrahedral crystals, and even hollow boxes, by an acid-base reaction and subsequent sequestration of leached metal ions. Etching tests on these ZIFs reveal that etching occurs preferentially in the crystallographic directions richer in metal-ligand bonds; that, along these directions, the etching rate tends to be faster on the crystal surfaces of higher dimensionality; and that the etching can be modulated by adjusting the pH of the etchant solution.
248 citations
TL;DR: In this article, it was shown that nanoparticles of [(Tb0.914Eu0.086)2(PDA)3(H2O)]·2H 2O (PDA = 1,4-phenylenediacetic acid), the first lanthanide-organic framework prepared by the spray-drying method, are excellent nanothermometers operating in the solid state in the 10-325 K range (quantum yield of 0.25 at 370 nm, at room temperature).
Abstract: Accurate, noninvasive, and self-referenced temperature measurements at the submicrometer scale are of great interest, prompted by the ever-growing demands in the fields of nanotechnology and nanomedicine. The thermal dependence of the phosphor's luminescence provides high detection sensitivity and spatial resolution with short acquisition times in, e.g., biological fluids, strong electromagnetic fields, and fast-moving objects. Here, it is shown that nanoparticles of [(Tb0.914Eu0.086)2(PDA)3(H2O)]·2H2O (PDA = 1,4-phenylenediacetic acid), the first lanthanide–organic framework prepared by the spray-drying method, are excellent nanothermometers operating in the solid state in the 10–325 K range (quantum yield of 0.25 at 370 nm, at room temperature). Intriguingly, this system is the most sensitive cryogenic nanothermometer reported so far, combining high sensitivity (up to 5.96 ± 0.04% K−1 at 25 K), reproducibility (in excess of 99%), and low-temperature uncertainty (0.02 K at 25 K).
237 citations
TL;DR: NanoMOFs were ranked according to their respective in vivo toxicity (in terms of the amount and severity of phenotypic changes observed in the treated zebrafish embryos), which varied widely, and show different levels of toxicity of these materials.
Abstract: Metal-organic frameworks (MOFs) are among the most attractive porous materials available today. They have garnered much attention for their potential utility in many different areas such as gas storage, separation, catalysis, and biomedicine. However, very little is known about the possible health or environmental risks of these materials. Here, the results of toxicity studies on sixteen representative uncoated MOF nanoparticles (nanoMOFs), which were assessed for cytotoxicity to HepG2 and MCF7 cells in vitro, and for toxicity to zebrafish embryos in vivo, are reported. Interestingly, there is a strong correlation between their in vitro toxicity and their in vivo toxicity. NanoMOFs were ranked according to their respective in vivo toxicity (in terms of the amount and severity of phenotypic changes observed in the treated zebrafish embryos), which varied widely. Altogether these results show different levels of toxicity of these materials; however, leaching of solubilized metal ions plays a main role.
179 citations
TL;DR: The methodology described here allows the liposome encapsulation of phages of different morphologies to be stored for at least 3 months at 4°C and could be added to the drinking water and feed of animals.
Abstract: Bacteriophages UAB_Phi20, UAB_Phi78, and UAB_Phi87 were encapsulated in liposomes, and their efficacy in reducing Salmonella in poultry was then studied. The encapsulated phages had a mean diameter of 309 to 326 nm and a positive charge between +31.6 and +35.1 mV (pH 6.1). In simulated gastric fluid (pH 2.8), the titer of nonencapsulated phages decreased by 5.7 to 7.8 log units, whereas encapsulated phages were significantly more stable, with losses of 3.7 to 5.4 log units. The liposome coating also improved the retention of bacteriophages in the chicken intestinal tract. When cocktails of the encapsulated and nonencapsulated phages were administered to broilers, after 72 h the encapsulated phages were detected in 38.1% of the animals, whereas the nonencapsulated phages were present in only 9.5%. The difference was significant. In addition, in an in vitro experiment, the cecal contents of broilers promoted the release of the phages from the liposomes. In broilers experimentally infected with Salmonella, the daily administration of the two cocktails for 6 days postinfection conferred similar levels of protection against Salmonella colonization. However, once treatment was stopped, protection by the nonencapsulated phages disappeared, whereas that provided by the encapsulated phages persisted for at least 1 week, showing the enhanced efficacy of the encapsulated phages in protecting poultry against Salmonella over time. The methodology described here allows the liposome encapsulation of phages of different morphologies. The preparations can be stored for at least 3 months at 4°C and could be added to the drinking water and feed of animals.
128 citations
TL;DR: An efficient, fast, and simple synthesis of an imine-based covalent organic framework (COF) at room temperature (hereafter, RT-COF-1) that shows a layered hexagonal structure exhibiting channels, is robust, and is porous to N2 and CO2.
Abstract: We report herein an efficient, fast, and simple synthesis of an imine-based covalent organic framework (COF) at room temperature (hereafter, RT-COF-1). RT-COF-1 shows a layered hexagonal structure exhibiting channels, is robust, and is porous to N2 and CO2 . The room-temperature synthesis has enabled us to fabricate and position low-cost micro- and submicropatterns of RT-COF-1 on several surfaces, including solid SiO2 substrates and flexible acetate paper, by using lithographically controlled wetting and conventional ink-jet printing.
114 citations
TL;DR: It is demonstrated that metal-organic frameworks (MOFs) can be replicated in a biomimetic fashion from protein patterns in a similar fashion to crime-scene investigation.
Abstract: It is demonstrated that metal-organic frameworks (MOFs) can be replicated in a biomimetic fashion from protein patterns. Bendable, fluorescent MOF patterns are formed with micrometer resolution under ambient conditions. Furthermore, this technique is used to grow MOF patterns from fingerprint residue in 30 s with high fidelity. This technique is not only relevant for crime-scene investigation, but also for biomedical applications.
94 citations
TL;DR: Spray-dry encapsulation of HKUST-1 crystals into polystyrene microspheres is reported here to yield composites that are resistant to water but retain most of the excellent gas sorption capacity of HKust-1.
Abstract: Metal–organic frameworks (MOFs) are an emerging class of porous materials comprising metal components and organic ligands. They are characterized by extremely large surface areas (SBET) and high structural/compositional flexibility that confer them with potential for myriad applications, including gas sorption and separation,[1] catalysis,[2] sensing[3] and biomedicine.[4] Seeking to exploit this exceptional porosity, researchers have spent the past 20 years bringing MOFs ever closer to real industrial applications. For instance, several fast, low-cost methods are currently being developed for industrial-scale synthesis and commercial distribution of MOFs.[5] However, major challenges must be overcome before MOFs find real-world utility. Among these is to improve their low hydrolytic stability, which prevents their use and storage in water-containing environments such as atmospheric conditions. Indeed, many polycarboxylate-based MOFs with high SBET (e.g. MOF-5 and HKUST-1) and exceptional promise for capture and storage of gasses (e.g. CO2, SO2 or CH4) are water labile.[6] Water molecules attack, and coordinate to, the metal ions in the constituent clusters of the MOFs, hydrolyzing the metal-ligand bonds and consequently, displacing the ligands. This leads to collapse of the MOFs,[7] ultimately compromising their sorption performance.[8]
86 citations
TL;DR: This paper describes the stepwise optimisation of reaction parameters (pH, reagent concentrations and reaction time) for the room temperature, water-based synthesis of several members of the CPO-27/MOF-74-M series of MOFs, including ones made from Mg(II), Ni, Ni, Co, Co and Zn(II) ions.
Abstract: The exceptional porosity of Metal–Organic Frameworks (MOFs) could be harnessed for countless practical applications. However, one of the challenges currently precluding the industrial exploitation of these materials is a lack of green methods for their synthesis. Since green synthetic methods obviate the use of organic solvents, they are expected to reduce the production costs, safety hazards and environmental impact typically associated with MOF fabrication. Herein we describe the stepwise optimisation of reaction parameters (pH, reagent concentrations and reaction time) for the room temperature, water-based synthesis of several members of the CPO-27/MOF-74-M series of MOFs, including ones made from Mg(II), Ni(II), Co(II) and Zn(II) ions. Using this method, we built MOFs with excellent BET surface areas and unprecedented Space-Time Yields (STYs). Employing this approach, we have synthesised CPO-27-M MOFs with record BET surface areas, including 1279 m2 g−1 (CPO-27-Zn), 1351 m2 g−1 (CPO-27-Ni), 1572 m2 g−1 (CPO-27-Co), and 1603 m2 g−1 (CPO-27-Mg). We anticipate that our method could be applied to produce CPO-27-Ni, -Mg, -Co and -Zn with STYs of 44 kg m−3 per day, 191 kg m−3 per day, 1462 kg m−3 per day and a record 18 720 kg m−3 per day, respectively.
72 citations
TL;DR: This innovative immunotherapy arrests the autoimmune aggression, reduces the severity of insulitis and prevents type 1 diabetes by apoptotic mimicry is concluded to constitute a promising strategy for autoimmune diseases.
Abstract: Introduction: The development of new therapies to induce self-tolerance has been an important medical health challenge in type 1 diabetes. An ideal immunotherapy should inhibit the autoimmune attack, avoid systemic side effects and allow a-cell regeneration. Based on the immunomodulatory effects of apoptosis, we hypothesized that apoptotic mimicry can help to restore tolerance lost in autoimmune diabetes.
Objective: To generate a synthetic antigen-specific immunotherapy based on apoptosis features to specifically reestablish tolerance to a-cells in type 1 diabetes.
Methods: A central event on the surface of apoptotic cells is the exposure of phosphatidylserine, which provides the main signal for efferocytosis. Therefore, phosphatidylserine-liposomes loaded with insulin peptides were generated to simulate apoptotic cells recognition by antigen presenting cells. The effect of antigen-specific phosphatidylserine-liposomes in the reestablishment of peripheral tolerance was assessed in NOD mice, the spontaneous model of autoimmune diabetes. MHC class II-peptide tetramers were used to analyze the T cell specific response after treatment with phosphatidylserine-liposomes loaded with peptides.
Results: We have shown that phosphatidylserine-liposomes loaded with insulin peptides induce tolerogenic dendritic cells and impair autoreactive T cell proliferation. When administered to NOD mice, liposome signal was detected in the pancreas and draining lymph nodes. This immunotherapy arrests the autoimmune aggression, reduces the severity of insulitis and prevents type 1 diabetes by apoptotic mimicry. MHC class II tetramer analysis showed that peptide-loaded phosphatidylserine-liposomes expand antigen-specific CD4+ T cells in vivo. The administration of phosphatidylserine-free liposomes emphasizes the importance of phosphatidylserine in the modulation of antigen-specific CD4+ T cell expansion.
Conclusions: We conclude that this innovative immunotherapy based on the use of liposomes constitutes a promising strategy for autoimmune diseases.
64 citations
TL;DR: In this paper, the synthesis of two new three-dimensional coordination polymers (CPs) based on Co(II), adenine, and aromatic tetracarboxylate linkers was reported.
Abstract: We report the synthesis of two new three-dimensional coordination polymers (CPs) based on Co(II), adenine, and aromatic tetracarboxylate linkers. Adenine exhibits bidentate binding modes in both CPs, coordinating through the N3 and N9 sites in a first compact CP and through the more rare N3 and N7 sites in a second open, flexible, and H2O-responsive CP. These differences together with an analysis of the extended coordination structures made of adenine reported in the Cambridge Structural Database illustrate the rich coordination versatility of adenine as a building block for CPs. Although the latter CP is nonporous to N2 or CO2, it shows a reversible and detectable color change from pink to purple, and vice versa, upon hydration and dehydration, respectively.
39 citations
TL;DR: The reaction of the chiral dipeptide glycyl-L(S)-glutamate with Co(II) ions produces chiral ladders that can be used as rigid 1D building units and enables the synthesis of a family of isoreticular MOFs, in which the pore size dictates the enantioselective adsorption of chiral molecules.
Abstract: This work was supported by the MINECO-Spain under the project PN MAT2012-30994. I.I. thanks the MINECO for the RyC fellowship and K.C.S. is grateful to EU for the Marie Curie Fellowship (300390 NanoBioMOFs FP7-PEOPLE-2011-IEF). The authors
thank the Diamond Light Source for access to beamline I19, which contributed to the results presented herein (MT8477). X.R. thanks for an ICREA Academia award. The project “Factoria de Cristalizacion, CONSOLIDER INGENIO-2010” provided PXRD
facilities. ICN2 acknowledges support of the Spanish MINECO through the Severo Ochoa Centers of Excellence Program under Grant SEV-2013-0295.
TL;DR: In this paper, a new healing surface coating technology based on the incorporation of hybrid melamine-formaldehyde-polyurethane (MF/PU) microcapsules which contain a healing mixture was described.
Abstract: A new healing surface coating technology based on the incorporation of hybrid melamine-formaldehyde–polyurethane (MF/PU) microcapsules which contain a healing mixture, into standard polyurethane surface coatings, is described. Microcapsules release the healing mixture upon surface scratching after mechanical damage.
TL;DR: In this article, it was shown that resonant spin tunneling in a molecular magnet can be established in a powder sample, without the need for a single crystal and without aligning the easy magnetization axes of the molecules.
Abstract: We report measurements and theoretical analysis of resonant spin tunneling in randomly oriented nanospheres of a molecular magnet. Amorphous nanospheres of ${\mathrm{Mn}}_{12}$ acetate have been fabricated and characterized by chemical, infrared, TEM, x-ray, and magnetic methods. Magnetic measurements have revealed sharp tunneling peaks in the field derivative of the magnetization that occur at the typical resonant field values for the ${\mathrm{Mn}}_{12}$ acetate crystal in the field parallel to the easy axis. Theoretical analysis is provided that explains these observations. We argue that resonant spin tunneling in a molecular magnet can be established in a powder sample, without the need for a single crystal and without aligning the easy magnetization axes of the molecules. This is confirmed by reanalyzing the old data on a powdered sample of nonoriented micron-size crystals of ${\mathrm{Mn}}_{12}$ acetate. Our findings can greatly simplify the selection of candidates for quantum spin tunneling among newly synthesized molecular magnets.
Posted Content•
TL;DR: In this paper, the magnetic properties of mixtures of micrometer-size ribbons of Mn$12$ acetate and particles of YBaCuO superconductor were characterized.
Abstract: We report characterization and magnetic studies of mixtures of micrometer-size ribbons of Mn$_{12}$ acetate and micrometer-size particles of YBaCuO superconductor. Extremely narrow zero-field spin-tunneling resonance has been observed in the mixtures, pointing to the absence of the inhomogeneous dipolar broadening. It is attributed to the screening of the internal magnetic fields in the magnetic particles by Josephson currents between superconducting grains surrounding the particles.
TL;DR: It is reported on page 7293 that metal-organic frameworks (MOFs) can be replicated in a biomimetic fashion from protein patterns on a surface in high fidelity.
Abstract: K. Liang, P. Falcaro, and co-workers report on page 7293 that metal-organic frameworks (MOFs) can be replicated in a biomimetic fashion from protein patterns on a surface. Bendable, fluorescent MOF patterns are formed with micrometer resolution under ambient conditions. This technique is used to grow MOF patterns from fingerprint residue in 30 s with high fidelity. This technique is not only relevant for crime-scene investigation, but also for biomedical applications.