Encapsulação de cafeína e diclofnac em carvão activado e MOF ZIF-8

Neste trabalho desenvolveu-se uma metodologia experimental que utiliza uma técnica de cromatografia frontal num sistema HPLC, com o intuito de medir isotérmicas de adsorção da cafeína e do diclofnac (este conhecido como Voltaren), permitindo medir o grau de encapsulação e a eficiência da libertação controlada. Serão testados dois tipos materiais porosos: o MOF ZIF -8, e o carvão ativado Norit SX PLUS como potencias sistemas de encapsulação e libertação controlada

Novel antibacterial azelaic acid BioMOFs

The development of metal-organic frameworks (MOFs) for bioapplications has gained great relevance over the last few years, mainly due to their potential as drug carriers and/or imaging agents. Although the bioactive azelaic acid has also been widely used as an antibacterial and anti-inflammatory drug, it presents low solubility, so of utmost importance is the development of more soluble formulations with sustained activity. In this contribution, we prove that new azelaic acid based metal biomolecule frameworks (BioMOFs) are a viable pathway to achieve this goal. Therefore, five novel MOFs were prepared by a simple, low-cost, and environmentally friendly mechanochemical approach, combining azelaic acid with endogenous cations (i.e., K+, Na+, and Mg2+): [K-2(H(2)AZE)(AZE)] (1), [Na-4(HAZE)(4)] (2), [Na-2(AZE)-(H2O)] (3), and two different polymorphic forms of [Mg(AZE)(H2O)(3)] (4) and (5) (where H(2)AZE - neutral azelaic acid; HAZE - mono-deprotonated azelaic acid; AZE - di-deprotonated azelaic acid). After full structural characterization using single-crystal X-ray diffraction data and other complementary standard solid-state techniques, their thermal and moisture stabilities as well as aqueous solubility were assessed. Finally, their antibacterial activity was evaluated against two Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis), commonly present on the skin. All MOF materials exhibit good stability and higher solubility than azelaic acid. In addition, BioMOF 1 has shown good antibacterial activity both at pH 5 and 6.5. Thus, 1 has shown to be a promising candidate to further develop new topical formulations of H(2)AZE

Modulation of the biocompatibility of collagen/polyelectrolyte semi-IPN hydrogels with Zn-bioMOFs

Abstract Background and purpose In this study, we examined the impact of Zn-bioMOF structures on the physical and chemical characteristics as well as the in vitro biocompatibility of a matrix composed of semi-interpenetrating polymeric networks (semi-IPN) made from collagen and L-tyrosine-based polyelectrolytes. Experimental approach We hydrothermally synthesized L-1, ZIF-8H Zn-bioMOFs, and the Zn-(L-His)2 complex, utilizing L-histidine, a bioactive amino acid, as a ligand. These metal-organic compounds primarily enhance the mechanical properties of the novel composite hydrogels through physical interactions such as hydrogen bonds and dipolar interactions. They also accelerate the gelation process. Composites containing Zn-bioMOFs exhibited greater biocompatibility than the collagen/polyelectrolyte matrix alone, as evidenced by cytotoxicity assays conducted with porcine fibroblasts, human monocytes, and RAW 264.7 cells. Furthermore, the evaluated materials did not exhibit hemolysis. We investigated the influence of Zn-bioMOFs on cell signaling by measuring the levels of crucial cytokines involved in the healing process, such as MCP-1, TGF-β, IL-10, and TNF-α secreted by human monocytes. Key results The composite with Zn(L-His)2 promoted the secretion of MCP-1, TGF-β, and IL-10, while a decrease in TNF-α secretion was observed with the composite containing ZIF-8H. Zn-bioMOFs enhanced certain aspects of the biomedical and physicochemical properties of the composite hydrogels. Conclusion Although the overall performance of the tested materials did not differ significantly, it is worth noting that the presence of Zn-bioMOFs in biopolymeric hydrogels modulated the metabolic activity of cells important for healing and their cytokine signaling, leading to improved biomedical performance

Facile, fast and green synthesis of a highly porous calcium-syringate bioMOF with intriguing triple bioactivity

A facile, fast and green strategy based on ethanol is utilized to prepare a new bioMOF, namely, CaSyr-1, with particular characteristics of full biocompatibility given by using just calcium and syringic acid, the latter being a phenolic natural product found in fruits and vegetables, permanent porosity with an outstanding surface area >1000 m2 g−1, and a micropore diameter of 1.4 nm close to mesopore values. Collectively, these data establish CaSyr-1 as one of the most porous bioMOFs reported to date, with high molecular adsorption capacity. The CaSyr-1 adsorptive behavior is revised here through the reversible adsorption of CO2 and the encapsulation of bioactive ingredients in the structure. Remarkably, CaSyr-1 enables the development of triple therapeutic entities, involving bioactive Ca2+, syringic acid and an impregnated drug

A 12-fold ths interpenetrated network utilizing a glycine-based pseudopeptidic ligand

We report the synthesis and characterization of a 3D Cu(II) coordination polymer, [Cu3(L1)2(H2O)8]·8H2O (1), with the use of a glycine-based tripodal pseudopeptidic ligand (H3L1 = N,N’,N’’-tris(carboxymethyl)-1,3,5-benzenetricarboxamide or trimesoyl-tris-glycine). This compound presents the first example of a 12-fold interpenetrated ths net. We attempt to justify the unique topology of 1 through a systematic comparison of the synthetic parameters in all reported structures with H3L1 and similar tripodal pseudopeptidic ligands. We additionally explore the catalytic potential of 1 in the A3 coupling reaction for the synthesis of propargylamines. The compound acts as a very good heterogeneous catalyst with yields up to 99% and loadings as low as 3 mol%

Missing linkers : an alternative pathway to UiO-66 electronic structure engineering

UiO-66 is a promising metal-organic framework for photocatalytic applications. However, the ligand-to-metal charge transfer of an excited electron is inefficient in the pristine material. Herein, we assess the influence of missing linker defects on the electronic structure of UiO-66 and discuss their ability to improve ligand-to-metal charge transfer. Using a new defect classification system, which is transparent and easily extendable, we identify the most promising photocatalysts by considering both relative stability and electronic structure. We find that the properties of UiO-66 defect structures largely depend on the coordination of the constituent nodes and that the nodes with the strongest local distortions alter the electronic structure most. Defects hence provide an alternative pathway to tune UiO-66 for photocatalytic purposes, besides linker modification and node metal substitution. In addition, the decomposition of MOF properties into node- and linker-based behavior is more generally valid, so we propose orthogonal electronic structure tuning as a paradigm in MOF design

Structure of the FeBTC Metal\u2013Organic Framework: A Model Based on the Local Environment Study

The local environment of iron in FeBTC, a metal organic framework commercially known as Basolite F300, is investigated combining XANES and EXAFS studies of the iron K-edge. The building block of the FeBTC can be described as an iron acetate moiety. Dehydration induces a change in the coordination of the first shell while preserving the network. We propose that the local structure around Fe atoms does not undergo a rearrangement, thus, leading to the formation of an open site. The analysis conveys that the FeBTC is a disordered network of locally ordered blocks

Selective Surface PEGylation of UiO-66 Nanoparticles for Enhanced Stability, Cell Uptake, and pH-Responsive Drug Delivery.

The high storage capacities and excellent biocompatibilities of metal-organic frameworks (MOFs) have made them emerging candidates as drug-delivery vectors. Incorporation of surface functionality is a route to enhanced properties, and here we report on a surface-modification procedure-click modulation-that controls their size and surface chemistry. The zirconium terephthalate MOF UiO-66 is (1) synthesized as ∼200 nm nanoparticles coated with functionalized modulators, (2) loaded with cargo, and (3) covalently surface modified with poly(ethylene glycol) (PEG) chains through mild bioconjugate reactions. At pH 7.4, the PEG chains endow the MOF with enhanced stability toward phosphates and overcome the "burst release" phenomenon by blocking interaction with the exterior of the nanoparticles, whereas at pH 5.5, stimuli-responsive drug release is achieved. The mode of cellular internalization is also tuned by nanoparticle surface chemistry, such that PEGylated UiO-66 potentially escapes lysosomal degradation through enhanced caveolae-mediated uptake. This makes it a highly promising vector, as demonstrated for dichloroacetic-acid-loaded materials, which exhibit enhanced cytotoxicity. The versatility of the click modulation protocol will allow a wide range of MOFs to be easily surface functionalized for a number of applications

Polypyrrole‐Decorated 2D Zn BioMOFs for Enhanced Supercapacitor Electrodes and Antibacterial Performance

Metal–organic frameworks (MOFs) possess high surface area and tunable porosity but suffer from poor conductivity, limiting their electrochemical performance. In this study, a zinc azelate Bio‐MOF (Zn‐Aza) was synthesized via a simple hydrothermal method and modified through in situ polymerization of pyrrole to form a conductive Zn‐Aza/Ppy composite. The 2D platelet‐like Zn‐Aza/Ppy structure offers enhanced surface area and porosity, facilitating ion diffusion and improving charge storage. Electrochemical analysis revealed that the specific capacitance of Zn‐Aza (≈714 mF cm−2) increased nearly fourfold after polypyrrole modification, maintaining ≈90% capacitance retention after 1000 cycles. Beyond energy storage, Zn‐Aza/Ppy composite exhibited strong antibacterial activity against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and methicillin‐resistant Staphylococcus aureus (MRSA) strains. The Bio‐MOFs were more effective against Gram‐positive bacteria attributed to the synergistic action of zinc ions, azelaic acid, and polypyrrole. These components disrupt bacterial membranes and enzymatic systems, interfere with metabolism and replication, and induce electrostatic damage. Overall, the conductive Zn‐Aza/Ppy nanocomposite demonstrates excellent electrochemical performance and potent antibacterial properties, establishing it as a promising multifunctional material for both supercapacitor and antimicrobial applications