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1.
Methods ; 212: 39-57, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36934614

RESUMO

Nanocomposites and low-viscous materials lack translation in additive manufacturing technologies due to deficiency in rheological requirements and heterogeneity of their preparation. This work proposes the chemical crosslinking between composing phases as a universal approach for mitigating such issues. The model system is composed of amine-functionalized bioactive glass nanoparticles (BGNP) and light-responsive methacrylated bovine serum albumin (BSAMA) which further allows post-print photocrosslinking. The interfacial interaction was conducted by 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide crosslinking agent and N-Hydroxysuccinimide between BGNP-grafted amines and BSAMA's carboxylic groups. Different chemical crosslinking amounts and percentages of BGNP in the nanocomposites were tested. The improved interface interactions increased the elastic and viscous modulus of all formulations. More pronounced increases were found with the highest crosslinking agent amounts (4 % w/v) and BGNP concentrations (10 % w/w). This formulation also displayed the highest Young's modulus of the double-crosslinked construct. All composite formulations could effectively immobilize the BGNP and turn an extremely low viscous material into an appropriate inks for 3d printing technologies, attesting for the systems' tunability. Thus, we describe a versatile methodology which can successfully render tunable and light-responsive nanocomposite inks with homogeneously distributed bioactive fillers. This system can further reproducibly recapitulate phases of other natures, broadening applicability.


Assuntos
Tinta , Nanopartículas , Engenharia Tecidual/métodos , Impressão Tridimensional , Reologia
2.
Biomacromolecules ; 24(7): 3380-3396, 2023 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-37337408

RESUMO

Dynamic G-quadruplex supramolecular hydrogels have aroused great interest in a broad range of bioapplications. However, neither the development of native extracellular matrix (ECM)-derived natural biopolymer-functionalized G-quadruplex hydrogels nor their use to create perfusable self-supporting hydrogels has been explored to date, despite their intrinsic potential as carrier vehicles of therapeutic agents, or even living cells in advanced regenerative therapies, or as platforms to enable the diffusion of nutrients and oxygen to sustain long-term cell survival. Herein, we developed a dynamic co-assembling multicomponent system that integrates guanosine (G), 3-aminophenylboronic acid functionalized hyaluronic acid (HA-PBA), and potassium chloride to bioengineer strong, homogeneous, and transparent HA-functionalized G-quadruplex hydrogels with injectable, thermo-reversible, conductive, and self-healing properties. The supramolecular polymeric hydrogels were developed by hydrogen bonding and π-π stacking interactions between G coupled via dynamic covalent boronate ester bonds to HA-PBA and stabilized by K+ ions, as demonstrated by a combination of experiments and molecular dynamics simulations. The intrinsic instability of the self-assembled G-quadruplex structures was used to bioengineer self-supporting perfusable multicomponent hydrogels with interconnected size and shape-tunable hollow microchannels when embedded in 3D methacrylated gelatin supporting matrices. The microchannel-embedded 3D constructs have shown enhanced cell viability when compared to the bulk hydrogels, holding great promise for being use as artificial vessels for enabling the diffusion of nutrients and oxygen essential for cell survival. The proposed approach opens new avenues on the use of ECM-derived natural biopolymer-functionalized dynamic G-quadruplex hydrogels to design next-generation smart systems for being used in tissue regeneration, drug screening, or organ-on-a-chip.


Assuntos
Ácido Hialurônico , Hidrogéis , Ácido Hialurônico/química , Hidrogéis/química , Matriz Extracelular/química , Gelatina/química
3.
Mar Drugs ; 21(2)2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36827133

RESUMO

Marine-origin polysaccharides, in particular cationic and anionic ones, have been widely explored as building blocks in fully natural or hybrid electrostatic-driven Layer-by-Layer (LbL) assemblies for bioapplications. However, the low chemical versatility imparted by neutral polysaccharides has been limiting their assembly into LbL biodevices, despite their wide availability in sources such as the marine environment, easy functionality, and very appealing features for addressing multiple biomedical and biotechnological applications. In this work, we report the chemical functionalization of laminarin (LAM) and pullulan (PUL) marine polysaccharides with peptides bearing either six lysine (K6) or aspartic acid (D6) amino acids via Cu(I)-catalyzed azide-alkyne cycloaddition to synthesize positively and negatively charged polysaccharide-peptide conjugates. The successful conjugation of the peptides into the polysaccharide's backbone was confirmed by proton nuclear magnetic resonance and attenuated total reflectance Fourier-transform infrared spectroscopy, and the positive and negative charges of the LAM-K6/PUL-K6 and LAM-D6/PUL-D6 conjugates, respectively, were assessed by zeta-potential measurements. The electrostatic-driven LbL build-up of either the LAM-D6/LAM-K6 or PUL-D6/PUL-K6 multilayered thin film was monitored in situ by quartz crystal microbalance with dissipation monitoring, revealing the successful multilayered film growth and the enhanced stability of the PUL-based film. The construction of the PUL-peptide multilayered thin film was also assessed by scanning electron microscopy and its biocompatibility was demonstrated in vitro towards L929 mouse fibroblasts. The herein proposed approach could enable the inclusion of virtually any kind of small molecules in the multilayered assemblies, including bioactive moieties, and be translated into more convoluted structures of any size and geometry, thus extending the usefulness of neutral polysaccharides and opening new avenues in the biomedical field, including in controlled drug/therapeutics delivery, tissue engineering, and regenerative medicine strategies.


Assuntos
Polissacarídeos , Medicina Regenerativa , Animais , Camundongos , Eletricidade Estática , Peptídeos , Engenharia Tecidual
4.
Sensors (Basel) ; 21(5)2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33652615

RESUMO

Anionic species are one of the most common pollutants in residual and freshwaters. The presence of anthropogenic anions in water drastically increases the toxicity to living beings. Here, we report the preparation of a new optical active material based on tri(tosylamino)phthalocyanines grafted to ferromagnetic silica nanoparticles for anion detection and removal. The new unsymmetrical phthalocyanines (Pcs) proved to be excellent chemosensors for several anions (AcO-, Br-, Cl-, CN-, F-, H2PO4-, HSO4-, NO2-, NO3-, and OH-) in dimethyl sulfoxide (DMSO). Furthermore, the Pcs were grafted onto magnetic nanoparticles. The resulting novel hybrid material showed selectivity and sensitivity towards CN-, F-, and OH- anions in DMSO with limit of detection (LoD) of ≈4.0 µM. In water, the new hybrid chemosensor demonstrated selectivity and sensitivity for CN- and OH- anions with LoD of ≈0.2 µM. The new hybrids are easily recovered using a magnet, allowing recyclability and reusability, after acidic treatment, without losing the sensing proprieties.

5.
J Am Chem Soc ; 142(46): 19689-19697, 2020 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-33166121

RESUMO

With society's growing awareness of climate change, novel renewable and naturally sourced materials have received increasing attention as substitutes for petroleum-based products. Laminarin (LAM-OH) is a highly abundant, nontoxic, degradable polysaccharide found in marine organisms and hence is a promising sustainable polymeric candidate. This work reports on a simple, environmentally friendly, and customizable functionalization strategy for producing a toolbox of LAM-OH derivatives under mild conditions. Herein, natural-origin macromolecules exhibiting specific chemical moieties, namely, allyl, amine, carboxylic acid, thiol, aldehyde, and catechol, were prepared and chemically characterized. Furthermore, the obtained polymers were processed into cytocompatible hydrogels, obtained by employing distinct cross-linking mechanisms, to assess their potential for biomedical purposes. The application scope of such polymers could be extended to fields such as catalysis, cosmetics, life sciences, and food packaging, which can also benefit from having sustainable, nontoxic, and degradable materials. Moreover, it is anticipated that the methodology employed to create this library of new natural-based products could be adapted to modify other polysaccharides and biopolymers in general.

6.
Bioconjug Chem ; 29(1): 176-181, 2018 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-29216717

RESUMO

Exploitation of photosensitizers as payloads for antibody-based anticancer therapeutics offers a novel alternative to the small pool of commonly utilized cytotoxins. However, existing bioconjugation methodologies are incompatible with the requirement of increased antibody loading without compromising antibody function, stability, or homogeneity. Herein, we describe the first application of dendritic multiplier groups to allow the loading of more than 4 porphyrins to a full IgG antibody in a site-specific and highly homogeneous manner. Photophysical evaluation of UV-visible absorbance and singlet oxygen quantum yields highlighted porphyrin-dendron 14 as the best candidate for bioconjugation; with subsequent bioconjugation producing a HER2-targeted therapeutic with average loading ratios of 15.4:1. In vitro evaluation of conjugate 18 demonstrated a nanomolar photocytotoxic effect in a target cell line, which overexpresses HER2, with no observed photocytotoxicity at the same concentration in a control cell line which expresses native HER2 levels, or in the absence of irradiation with visible light.


Assuntos
Dendrímeros/química , Imunoconjugados/química , Imunoglobulina G/química , Fármacos Fotossensibilizantes/química , Porfirinas/química , Trastuzumab/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dendrímeros/farmacologia , Sistemas de Liberação de Medicamentos , Humanos , Imunoconjugados/farmacologia , Imunoglobulina G/farmacologia , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Fármacos Fotossensibilizantes/farmacologia , Porfirinas/farmacologia , Receptor ErbB-2/análise , Receptor ErbB-2/metabolismo , Trastuzumab/farmacologia
7.
Int J Cancer ; 141(7): 1478-1489, 2017 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-28639285

RESUMO

Gastric cancer (GC) is the 3rd deadliest cancer worldwide, due to limited treatment options and late diagnosis. Human epidermal growth factor receptor-2 (HER2) is overexpressed in ∼20% of GC cases and anti-HER2 antibody trastuzumab in combination with conventional chemotherapy, is recognized as standard therapy for HER2-positive metastatic GC. This strategy improves GC patients' survival by 2-3 months, however its optimal results in breast cancer indicate that GC survival may be improved. A new photoimmunoconjugate was developed by conjugating a porphyrin with trastuzumab (Trast:Porph) for targeted photodynamic therapy in HER2-positive GC. Using mass spectrometry analysis, the lysine residues in the trastuzumab structure most prone for porphyrin conjugation were mapped. The in vitro data demonstrates that Trast:Porph specifically binds to HER2-positive cells, accumulates intracellularly, co-localizes with lysosomal marker LAMP1, and induces massive HER2-positive cell death upon cellular irradiation. The high selectivity and cytotoxicity of Trast:Porph based photoimmunotherapy is confirmed in vivo in comparison with trastuzumab alone, using nude mice xenografted with a HER2-positive GC cell line. In the setting of human disease, these data suggest that repetitive cycles of Trast:Porph photoimmunotherapy may be used as an improved treatment strategy in HER2-positive GC patients.


Assuntos
Antineoplásicos/uso terapêutico , Morte Celular , Imunoterapia/métodos , Fotoquimioterapia/métodos , Porfirinas/uso terapêutico , Receptor ErbB-2 , Neoplasias Gástricas/tratamento farmacológico , Trastuzumab/uso terapêutico , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Lisina/química , Proteínas de Membrana Lisossomal/farmacocinética , Masculino , Espectrometria de Massas , Camundongos Nus , Porfirinas/química , Porfirinas/farmacocinética , Distribuição Aleatória , Neoplasias Gástricas/metabolismo , Trastuzumab/química , Trastuzumab/farmacocinética , Ensaios Antitumorais Modelo de Xenoenxerto
8.
Org Biomol Chem ; 15(25): 5402-5409, 2017 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-28627569

RESUMO

The development of methods for the generation of site-selective interstrand crosslinks (ICLs) in synthetic oligonucleotides provides a platform for the study of ICL repair mechanisms and the stabilisation of DNA-based materials. Our group has previously reported on the use of a furan moiety as a masked reactive functionality for ICL generation and recently introduced the use of 1O2 as an efficient light-induced oxidant. Here, the use of porphyrin-based photosensitizers (PSs) has been explored for ICL generation. The efficiency of the ICL reaction has been investigated using PSs added into solution as well as attached to oligonucleotide probes. Interestingly, even a highly hydrophobic phthalocyanine was able to produce ICLs. Either in solution or conjugated to an ON, chlorin e6 was the most efficient ICL generator for the current purpose.


Assuntos
Reagentes de Ligações Cruzadas/síntese química , DNA/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/síntese química , Porfirinas/química , Oxigênio Singlete/química , Reagentes de Ligações Cruzadas/química , Estrutura Molecular
9.
BMC Bioinformatics ; 17: 59, 2016 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-26842742

RESUMO

BACKGROUND: The second Chargaff's parity rule and its extensions are recognized as universal phenomena in DNA sequences. However, parity of the frequencies of reverse complementary oligonucleotides could be a mere consequence of the single nucleotide parity rule, if nucleotide independence is assumed. Exceptional symmetry (symmetry beyond that expected under an independent nucleotide assumption) was proposed previously as a meaningful measure of the extension of the second parity rule to oligonucleotides. The global exceptional symmetry was detected in long and short genomes. RESULTS: To explore the exceptional genomic word symmetry along the genome sequences, we propose a sliding window method to extract the values of exceptional symmetry (for all words or by word groups). We compare the exceptional symmetry effect size distribution in all human chromosomes against control scenarios (positive and negative controls), testing the differences and performing a residual analysis. We explore local exceptional symmetry in equivalent composition word groups, and find that the behaviour of the local exceptional symmetry depends on the word group. CONCLUSIONS: We conclude that the exceptional symmetry is a local phenomenon in genome sequences, with distinct characteristics along the sequence of each chromosome. The local exceptional symmetry along the genomic sequences shows outlying segments, and those segments have high biological annotation density.


Assuntos
Cromossomos Humanos/genética , DNA/genética , Genoma Humano , Modelos Genéticos , Modelos Estatísticos , Genômica , Humanos , Transcriptoma
10.
Biostatistics ; 16(2): 209-21, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25190514

RESUMO

Some previous studies suggest the extension of Chargaff's second rule (the phenomenon of symmetry in a single DNA strand) to long DNA words. However, in random sequences generated under an independent symbol model where complementary nucleotides have equal occurrence probabilities, we expect the phenomenon of symmetry to hold for any word length. In this work, we develop new statistical methods to measure the exceptional symmetry. Exceptional symmetry is a refinement of Chargaff's second parity rule that highlights the words whose frequency of occurrence is similar to that of its reversed complement but dissimilar to the frequencies of occurrence of other words which contain the same number of nucleotides A or T. We analyze words of lengths up to 12 in the complete human genome and in each chromosome separately. We assess exceptional symmetry globally, by word group, and by word. We conclude that the global symmetry present in the human genome is clearly exceptional and significant. The chromosomes present distinct exceptional symmetry profiles. There are several exceptional word groups and exceptional words with a strong exceptional symmetry.


Assuntos
DNA/genética , Genoma Humano/genética , Modelos Genéticos , Modelos Estatísticos , Humanos
11.
ACS Appl Polym Mater ; 6(11): 6820-6830, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38903401

RESUMO

Food smart packaging has emerged as a promising technology to address consumer concerns regarding food conservation and food safety. In this context, we report the rational design of azide-containing pyranoflavylium-based pH-sensitive dye for subsequent click chemistry conjugation toward a chitosan-modified alkyne. The chitosan-pyranoflavylium conjugate was characterized by infrared (ATR-FTIR), ultraviolet-visible (UV-vis), nuclear magnetic resonance (NMR) spectroscopies, and dynamic light scattering (DLS), as well as its thermodynamic parameters related to their pH-dependent chromatic features. The fabrication of thin-films through electrostatic-driven layer-by-layer (LbL) assembly technology was first screened by quartz crystal microbalance with dissipation monitoring (QCM-D) onto gold substrates, and then free-standing (FS) multilayered membranes from polypropylene substrate were obtained using a homemade automatic dipping robot. The membranes' characterization included morphology analysis and thickness evaluation, assessed by scanning electron microscopy (SEM), pH-responsive color change performance tests using buffer solutions at different pH levels, and biogenic amines-enriched model solutions, demonstrating the feasibility and effectiveness of the chitosan-pyranoflavylium/alginate biomembranes for food spoilage monitoring. This work provides insights toward the development of innovative pH-responsive smart biomaterials for advanced and sustainable technological packaging solutions, which could significantly contribute to ensuring food safety and quality, while reducing food waste.

12.
ACS Appl Mater Interfaces ; 16(15): 18386-18399, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38591243

RESUMO

Cryogels exhibit unique shape memory with full recovery and structural stability features after multiple injections. These constructs also possess enhanced cell permeability and nutrient diffusion when compared to typical bulk hydrogels. Volumetric processing of cryogels functionalized with nanosized units has potential to widen their biomedical applications, however this has remained challenging and relatively underexplored. In this study, we report a novel methodology that combines suspension 3D printing with directional freezing for the fabrication of nanocomposite cryogels with configurable anisotropy. When compared to conventional bulk or freeze-dried hydrogels, nanocomposite cryogel formulations exhibit excellent shape recovery (>95%) and higher pore connectivity. Suspension printing, assisted with a prechilled metal grid, was optimized to induce anisotropy. The addition of calcium- and phosphate-doped mesoporous silica nanoparticles into the cryogel matrix enhanced bioactivity toward orthopedic applications without hindering the printing process. Notably, the nanocomposite 3D printed cryogels exhibit injectable shape memory while also featuring a lamellar topography. The fabrication of these constructs was highly reproducible and exhibited potential for a cell-delivery injectable cryogel with no cytotoxicity to human-derived adipose stem cells. Hence, in this work, it was possible to combine a gravity defying 3D printed methodology with injectable and controlled anisotropic macroporous structures containing bioactive nanoparticles. This methodology ameliorates highly tunable injectable 3D printed anisotropic nanocomposite cryogels with a user-programmable degree of structural complexity.


Assuntos
Criogéis , Impressão Tridimensional , Humanos , Criogéis/química , Anisotropia , Adipócitos , Engenharia Tecidual/métodos , Alicerces Teciduais/química
13.
Adv Healthc Mater ; 13(13): e2304587, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38334308

RESUMO

Medical adhesives are emerging as an important clinical tool as adjuvants for sutures and staples in wound closure and healing and in the achievement of hemostasis. However, clinical adhesives combining cytocompatibility, as well as strong and stable adhesion in physiological conditions, are still in demand. Herein, a mussel-inspired strategy is explored to produce adhesive coacervates using tannic acid (TA) and methacrylate pullulan (PUL-MA). TA|PUL-MA coacervates mainly comprise van der Waals forces and hydrophobic interactions. The methacrylic groups in the PUL backbone increase the number of interactions in the adhesives matrix, resulting in enhanced cohesion and adhesion strength (72.7 Jm-2), compared to the non-methacrylated coacervate. The adhesive properties are kept in physiologic-mimetic solutions (72.8 Jm-2) for 72 h. The photopolymerization of TA|PUL-MA enables the on-demand detachment of the adhesive. The poor cytocompatibility associated with the use of phenolic groups is here circumvented by mixing reactive oxygen species-degrading enzyme in the adhesive coacervate. This addition does not hamper the adhesive character of the materials, nor their anti-microbial or hemostatic properties. This affordable and straightforward methodology, together with the tailorable adhesivity even in wet environments, high cytocompatibility, and anti-bacterial activity, enables foresee TA|PUL-MA as a promising ready-to-use bioadhesive for biomedical applications.


Assuntos
Antibacterianos , Taninos , Antibacterianos/química , Antibacterianos/farmacologia , Taninos/química , Taninos/farmacologia , Animais , Polifenóis/química , Polifenóis/farmacologia , Adesivos/química , Adesivos/farmacologia , Glucanos/química , Glucanos/farmacologia , Humanos , Camundongos , Escherichia coli/efeitos dos fármacos , Metacrilatos/química , Polímeros/química , Polímeros/farmacologia , Adesivos Teciduais/química , Adesivos Teciduais/farmacologia
14.
J Theor Biol ; 335: 153-9, 2013 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-23831271

RESUMO

Previous studies have suggested that Chargaff's second rule may hold for relatively long words (above 10nucleotides), but this has not been conclusively shown. In particular, the following questions remain open: Is the phenomenon of symmetry statistically significant? If so, what is the word length above which significance is lost? Can deviations in symmetry due to the finite size of the data be identified? This work addresses these questions by studying word symmetries in the human genome, chromosomes and transcriptome. To rule out finite-length effects, the results are compared with those obtained from random control sequences built to satisfy Chargaff's second parity rule. We use several techniques to evaluate the phenomenon of symmetry, including Pearson's correlation coefficient, total variational distance, a novel word symmetry distance, as well as traditional and equivalence statistical tests. We conclude that word symmetries are statistical significant in the human genome for word lengths up to 6nucleotides. For longer words, we present evidence that the phenomenon may not be as prevalent as previously thought.


Assuntos
Cromossomos Humanos/genética , Genoma Humano/fisiologia , Modelos Genéticos , Cromossomos Humanos/metabolismo , Humanos , Transcriptoma/fisiologia
15.
Biomater Adv ; 155: 213670, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37952461

RESUMO

Conventional surgical closure techniques, such as sutures, clips, or skin closure strips, may not always provide optimal wound closure and may require invasive procedures, which can result in potential post-surgical complications. As result, there is a growing demand for innovative solutions to achieve superior wound closure and improve patient outcomes. To overcome the abovementioned issues, in situ generated hemostatic adhesives/sealants have emerged as a promising alternative, offering a targeted, controllable, and minimally invasive procedure for a wide variety of medical applications. The aim of this review is to provide a comprehensive overview of the mechanisms of action and recent advances of in situ generated hemostatic adhesives, particularly protein-based, thermoresponsive, bioinspired, and photocrosslinkable formulations, as well as the design challenges that must be addressed. Overall, this review aims to enhance a comprehensive understanding of the latest advancements of in situ generated hemostatic adhesives and their mechanisms of action, with the objective of promoting further research in this field.


Assuntos
Hemostáticos , Adesivos Teciduais , Humanos , Adesivos/uso terapêutico , Adesivos Teciduais/uso terapêutico , Hemostáticos/uso terapêutico , Cicatrização , Técnicas de Fechamento de Ferimentos
16.
J Integr Bioinform ; 20(2)2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-37486620

RESUMO

This work aims to describe the observed enrichment of inverted repeats in the human genome; and to identify and describe, with detailed length profiles, the regions with significant and relevant enriched occurrence of inverted repeats. The enrichment is assessed and tested with a recently proposed measure (z-scores based measure). We simulate a genome using an order 7 Markov model trained with the data from the real genome. The simulated genome is used to establish the critical values which are used as decision thresholds to identify the regions with significant enriched concentrations. Several human genome regions are highly enriched in the occurrence of inverted repeats. This is observed in all the human chromosomes. The distribution of inverted repeat lengths varies along the genome. The majority of the regions with severely exaggerated enrichment contain mainly short length inverted repeats. There are also regions with regular peaks along the inverted repeats lengths distribution (periodic regularities) and other regions with exaggerated enrichment for long lengths (less frequent). However, adjacent regions tend to have similar distributions.

17.
Gels ; 9(2)2023 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-36826257

RESUMO

Adaptable hydrogels have been used in the biomedical field to address several pathologies, especially those regarding tissue defects. Here, we describe unprecedented catechol-like functionalized polyrotaxane (PR) polymers able to form hydrogels. PR were functionalized with the incorporation of hydroxypyridinone (HOPO) moieties into the polymer backbone, with a degree of substitution from 4 to 22%, depending on the PR type. The hydrogels form through the functionalized supramolecular systems when in contact with a Fe(III) solution. Despite the hydrogel formation being at physiological pH (7.4), the HOPO derivatives are extremely resistant to oxidation, unlike common catechols; consequently, they prevent the formation of quinones, which can lead to irreversible bounds within the matrix. The resulting hydrogels demonstrated properties lead to unique hydrogels with improved mechanical behavior obtained by metallic coordination crosslinking, due to the synergies of the sliding-ring PR and the non-covalent (reversible) catechol analogues. Following this strategy, we successfully developed innovative, cytocompatible, oxidative-resistant, and reversible crosslinked hydrogels, with the potential of being used as structural self-materials for a variety of applications, including in the biomedical field.

18.
J Mater Chem B ; 11(28): 6671-6684, 2023 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-37377032

RESUMO

The layer-by-layer (LbL) assembly technology has been widely used to functionalise surfaces and precisely engineer robust multilayered bioarchitectures with tunable structures, compositions, properties, and functions at the nanoscale by resorting to a myriad of building blocks exhibiting complementary interactions. Among them, marine-origin polysaccharides are a sustainable renewable resource for the fabrication of nanostructured biomaterials for biomedical applications owing to their wide bioavailability, biocompatibility, biodegradability, non-cytotoxicity, and non-immunogenic properties. Chitosan (CHT) and alginate (ALG) have been widely employed as LbL ingredients to shape a wide repertoire of size- and shape-tunable electrostatic-driven multilayered assemblies by exploring their opposite charge nature. However, the insolubility of CHT in physiological conditions intrinsically limits the range of bioapplications of the as-developed CHT-based LbL structures. Herein, we report the preparation of free-standing (FS) multilayered membranes made of water-soluble quaternised CHT and ALG biopolymers for controlled release of model drug molecules. The influence of the film structure in the drug release rate is studied by assembling two distinct set-ups of FS membranes, having the model hydrophilic drug fluorescein isothiocyanate-labelled bovine serum albumin (FITC-BSA) either as an intrinsic building block or added as an outer layer after the LbL assembly process. Both FS membranes are characterised for their thickness, morphology, in vitro cytocompatibility, and release profile, with those having FITC-BSA as an intrinsic LbL ingredient denoting a more sustained release rate. This work opens up new avenues for the design and development of a wide array of CHT-based devices for biomedical applications, overcoming the limitations associated with the insolubility of native CHT under physiological conditions.


Assuntos
Quitosana , Polissacarídeos , Materiais Biocompatíveis/química , Quitosana/química , Sistemas de Liberação de Medicamentos , Alginatos/química
19.
Adv Healthc Mater ; 12(28): e2301513, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37515450

RESUMO

The optimized physical adhesion between bees' leg hairs and pollen grains-whereby the latter's diameter aligns with the spacing between the hairs-has previously inspired the development of a biomimetic drug dressing. Combining this optimized process with the improved natural mussels' adhesion in wet environments in a dual biomimetic process, it is herein proposed the fabrication of a natural-derived micropatterned hydrogel patch of methacrylated laminarin (LAM-MET), with enriched drug content and improved adhesiveness, suitable for applications like wound healing. Enhanced adhesion is accomplished by modifying LAM-MET with hydroxypyridinone groups, following the patch microfabrication by soft lithography and UV/vis-irradiation, resulting in a membrane with micropillars with a high aspect ratio. Following the biomimetics rational, a drug patch is engineered by combining the microfabricated dressing with drug particles milled to fit the spaces between pillars. Controlled drug release is achieved, together with inherent antibacterial activity against Escherichia coli and Pseudomonas aeruginosa, and enhanced biocompatibility using the bare micropatterned patches. This new class of biomimetic dressings overcomes the challenges of current patches, like poor mechanical properties and biocompatibility, limited adhesiveness and drug dosage, and lack of prolonged antimicrobial activity, opening new insights for the development of high drug-loaded dressings with improved patient compliance.


Assuntos
Adesivos , Biomimética , Animais , Humanos , Adesivos/farmacologia , Biomimética/métodos , Hidrogéis/farmacologia , Liberação Controlada de Fármacos , Cicatrização , Antibacterianos/farmacologia
20.
Acta Crystallogr C ; 68(Pt 3): o104-7, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22382541

RESUMO

The title compound, C(48)H(20)F(19)N(4)O(3)P, prepared by the nucleophilic attack of triethyl phosphite on one of the 4-fluoro atoms of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin, contains a single molecule in the asymmetric unit. The porphyrin unit is almost planar [largest non-H atom deviation = 0.174 (6) Å], and has the planes of the neighbouring benzene rings oriented at angles ranging from 64.3 (2) to 89.6 (3)° relative to the porphyrin core. The P=O group is almost coplanar with the attached benzene ring, subtending an angle of 4.0 (3)°. Several weak supramolecular interactions, namely C-H...π, C-F...π, P=O...π, C-H...(O,F) and F...F contacts, contribute to the crystal packing.

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