RESUMO
Air pollution is an environmental factor associated with an increased risk of neurodegenerative diseases, such as Alzheimer's and Parkinson's, characterized by decreased cognitive abilities and memory. The limited models of sporadic Alzheimer's disease fail to replicate all pathological hallmarks of the disease, making it challenging to uncover potential environmental causes. Environmentally driven models of Alzheimer's disease are thus timely and necessary. We used live-cell confocal fluorescent imaging combined with high-resolution stimulated emission depletion (STED) microscopy to follow the response of retinoic acid-differentiated human neuroblastoma SH-SY5Y cells to nanomaterial exposure. Here, we report that exposure of the cells to some particulate matter constituents reproduces a neurodegenerative phenotype, including extracellular amyloid beta-containing plaques and decreased neurite length. Consistent with the existing in vivo research, we observed detrimental effects, specifically a substantial reduction in neurite length and formation of amyloid beta plaques, after exposure to iron oxide and diesel exhaust particles. Conversely, after exposure to engineered cerium oxide nanoparticles, the lengths of neurites were maintained, and almost no extracellular amyloid beta plaques were formed. Although the exact mechanism behind this effect remains to be explained, the retinoic acid differentiated SH-SY5Y cell in vitro model could serve as an alternative, environmentally driven model of neurodegenerative diseases, including Alzheimer's disease.
Assuntos
Peptídeos beta-Amiloides , Neuritos , Material Particulado , Proteínas tau , Humanos , Material Particulado/toxicidade , Neuritos/efeitos dos fármacos , Peptídeos beta-Amiloides/metabolismo , Linhagem Celular Tumoral , Proteínas tau/metabolismo , Placa Amiloide , Doença de Alzheimer/induzido quimicamente , Tretinoína/farmacologia , Nanopartículas/química , Nanopartículas/toxicidadeRESUMO
This study demonstrates the potential of gelatin nanoparticles as a nanodelivery system for antagonists of nicotinic acetylcholine receptors (nAChRs) to improve chemotherapy efficacy and reduce off-target effects. Too often, chemotherapy for lung cancer does not lead to satisfactory results. Therefore, new approaches directed at multiple pharmacological targets in cancer therapy are being developed. Following the activation of nAChRs (e.g. by nicotine), cancer cells begin to proliferate and become more resistant to chemotherapy-induced apoptosis. This work shows that the 3-alkylpyridinium salt, APS7, a synthetic analog of a toxin from the marine sponge Haliclona (Rhizoneira) sarai, acts as an nAChR antagonist that inhibits the pro-proliferative and anti-apoptotic effects of nicotine on A549 human lung adenocarcinoma cells. In this study, gelatin-based nanoparticles filled with APS7 (APS7-GNPs) were prepared and their effects on A549 cells were compared with that of free APS7. Both APS7 and APS7-GNPs inhibited Ca2+ influx and increased the efficacy of cisplatin chemotherapy in nicotine-stimulated A549 cells. However, significant benefits from APS7-GNPs were observed - a stronger reduction in the proliferation of A549 lung cancer cells and a much higher selectivity in cytotoxicity towards cancer cells compared with non-tumorigenic lung epithelial BEAS-2B cells.
Assuntos
Proliferação de Células , Gelatina , Neoplasias Pulmonares , Nanopartículas , Humanos , Gelatina/química , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/metabolismo , Células A549 , Nanopartículas/química , Proliferação de Células/efeitos dos fármacos , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Compostos de Piridínio/farmacologia , Compostos de Piridínio/química , Cisplatino/farmacologia , Nicotina/farmacologia , Antagonistas Nicotínicos/farmacologia , Antagonistas Nicotínicos/química , Linhagem Celular TumoralRESUMO
We report a series of coordination cages that incorporate peptide chains at their vertices, prepared through subcomponent self-assembly. Three distinct heterochiral tripeptide subcomponents were incorporated, each exhibiting an L-D-L stereoconfiguration. Through this approach, we prepared and characterized three tetrahedral metal-peptide cages that incorporate thiol and methylthio groups. The gelation of these cages was probed through the binding of additional metal ions, with the metal-peptide cages acting as junctions, owing to the presence of sulfur atoms on the peripheral peptides. Gels were obtained with cages bearing cysteine at the C-terminus. Our strategy for developing functional metal-coordinated supramolecular gels with a modular design may result in the development of materials useful for chemical separations or drug delivery.
Assuntos
Cisteína , Géis , Peptídeos , Cisteína/química , Peptídeos/química , Géis/química , Íons/química , Metais/química , Complexos de Coordenação/químicaRESUMO
Insulin fibrillation is a problem for diabetic patients that can occur during storage and transport, as well as at the subcutaneous injection site, with loss of bioactivity, inflammation, and various adverse effects. Tripeptides are ideal additives to stabilise insulin formulations, thanks to their low cost of production and inherent cytocompatibility. In this work, we analysed the ability of eight tripeptide stereoisomers to inhibit the fibrillation of human insulin in vitro. The sequences contain proline as ß-breaker and Phe-Phe as binding motif for the amyloid-prone aromatic triplet found in insulin. Experimental data based on spectroscopy, fluorescence, microscopy, and calorimetric techniques reveal that one stereoisomer is a more effective inhibitor than the others, and cell live/dead assays confirmed its high cytocompatibility. Importantly, in silico data revealed the key regions of insulin engaged in the interaction with this tripeptide, rationalising the molecular mechanism behind insulin fibril formation reduction.
Assuntos
Amiloide , Insulina , Oligopeptídeos , Insulina/química , Insulina/metabolismo , Humanos , Amiloide/química , Amiloide/metabolismo , Estereoisomerismo , Oligopeptídeos/química , Oligopeptídeos/farmacologiaRESUMO
Dipeptides stereoisomers and regioisomers composed of norleucine (Nle) and phenylalanine (Phe) self-assemble into hydrogels under physiological conditions that are suitable for cell culture. The supramolecular behavior, however, differs as the packing modes comprise amphipathic layers or water channels, whose diameter is defined by either four or six dipeptide molecules. A variety of spectroscopy, microscopy, and synchrotron-radiation-based techniques unveil fine details of intermolecular interactions that pinpoint the relationship between the chemical structure and ability to form supramolecular architectures that define soft biomaterials.
Assuntos
Dipeptídeos , Hidrogéis , Dipeptídeos/química , Hidrogéis/química , Água/química , Estereoisomerismo , MicroscopiaRESUMO
This study reports on the fabrication and assembly of anisotropic microparticles as versatile building blocks for directed magnetic assemblies. Although spherical microparticles have received extensive attention, the assembly of non-spherical magnetic microparticles remains underexplored. Herein, we present a fabrication approach that utilizes photolithography and soft lithography to create prism-shaped magnetic microparticles. In order to investigate their assembly, a switching rotating magnetic field was employed. To support our experimental findings, a numerical model which takes into account the magnetic dipole moments induced by the field of other particles was developed. This model helps in understanding the forces and torques governing particle behavior during assembly. Simulations were conducted using the numerical model to complement our experimental findings. In the two particle experiments, attractive magnetic interactions led to various configurations depending on initial positions. For three particles, a tip-to-tip configuration suggested closed or stable ring-like structures. Our work highlights the feasibility of producing highly responsive, non-spherical magnetic microparticles and their potential for assemblies. The versatile fabrication method, coupled with the added degree of freedom conferred by prismatic shapes, opens promising avenues for applications in biology and material science.
RESUMO
The divergent supramolecular behavior of a series of tripeptide stereoisomers was elucidated through spectroscopic, microscopic, crystallographic, and computational techniques. Only two epimers were able to effectively self-organize into amphipathic structures, leading to supramolecular hydrogels or crystals, respectively. Despite the similarity between the two peptides' turn conformations, stereoconfiguration led to different abilities to engage in intramolecular hydrogen bonding. Self-assembly further shifted the pKa value of the C-terminal side chain. As a result, across the pH range 4-6, only one epimer predominated sufficiently as a zwitterion to reach the critical molar fraction, allowing gelation. By contrast, the differing pKa values and higher dipole moment of the other epimer favored crystallization. The four stereoisomers were further tested for gold nanoparticle (AuNP) formation, with the supramolecular hydrogel being the key to control and stabilize AuNPs, yielding a nanocomposite that catalyzed the photodegradation of a dye. Importantly, the AuNP formation occurred without the use of reductants other than the peptide, and the redox chemistry was investigated by LC-MS, NMR, and infrared scattering-type near field optical microscopy (IR s-SNOM). This study provides important insights for the rational design of simple peptides as minimalistic and green building blocks for functional nanocomposites.
Assuntos
Hidrogéis , Nanopartículas Metálicas , Hidrogéis/química , Ouro/química , Nanopartículas Metálicas/química , Peptídeos/químicaRESUMO
Magneto-mechanical actuation (MMA) using the low-frequency alternating magnetic fields (AMFs) of magnetic nanoparticles internalized into cancer cells can be used to irreparably damage these cells. However, nanoparticles in cells usually agglomerate, thus greatly augmenting the delivered force compared to single nanoparticles. Here, we demonstrate that MMA also decreases the cell viability, with the MMA mediated by individual, non-interacting nanoparticles. The effect was demonstrated with ferrimagnetic (i.e., permanently magnetic) barium-hexaferrite nanoplatelets (NPLs, â¼50 nm wide and 3 nm thick) with a unique, perpendicular orientation of the magnetization. Two cancer-cell lines (MDA-MB-231 and HeLa) are exposed to the NPLs in-vitro under different cell-culture conditions and actuated with a uniaxial AMF. TEM analyses show that only a small number of NPLs internalize in the cells, always situated in membrane-enclosed compartments of the endosomal-lysosomal system. Most compartments contain 1-2 NPLs and only seldom are the NPLs found in small groups, but never in close contact or mutually oriented. Even at low concentrations, the single NPLs reduce the cell viability when actuated with AMFs, which is further increased when the cells are in starvation conditions. These results pave the way for more efficient in-vivo MMA at very low particle concentrations.
Assuntos
Nanopartículas , Neoplasias , Humanos , Campos Magnéticos , Células HeLa , LisossomosRESUMO
The surface of Carbon Nanodots (CNDs) stands as a rich chemical platform, able to regulate the interactions between particles and external species. Performing selective functionalization of these nanoscale entities is of practical importance, however, it still represents a considerable challenge. In this work, we exploited the organic chemistry toolbox to install target functionalities on the CND surface, while monitoring the chemical changes on the material's outer shell through nuclear magnetic resonance spectroscopy. Following this, we investigated the use of click chemistry to covalently connect CNDs of different nature en-route towards covalent suprastructures with unprecedent molecular control. The different photophysical properties of the connected particles allowed their optical communication in the excited state. This work paves the way for the development of selective and addressable CND building blocks which can act as modular nanoscale synthons that mirror the long-established reactivity of molecular organic synthesis.
RESUMO
Carbon nanostructures (CNSs) are attractive components to attain nanocomposites, yet their hydrophobic nature and strong tendency to aggregate often limit their use in aqueous conditions and negatively impact their properties. In this work, carbon nanohorns (CNHs), multi-walled carbon nanotubes (CNTs), and graphene (G) are first oxidized, and then reacted to covalently anchor the self-assembling tripeptide L-Leu-D-Phe-D-Phe to improve their dispersibility in phosphate buffer, and favor the formation of hydrogels formed by the self-organizing L-Leu-D-Phe-D-Phe present in solution. The obtained nanocomposites are then characterized by transmission electron microscopy (TEM), oscillatory rheology, and conductivity measurements to gain useful insights as to the key factors that determine self-healing ability for the future design of this type of nanocomposites.
RESUMO
To improve the physical stability of nanoparticle dispersions, several methods for their transformation into stable and easily dispersible dry products have been investigated thus far. Recently, electrospinning was shown to be a novel nanoparticle dispersion drying method, which addresses the crucial challenges of the current drying methods. It is a relatively simple method, but it is affected by various ambient, process, and dispersion parameters, which impact the properties of the electrospun product. The aim of this study was, thus, to investigate the influence of the most important dispersion parameter, namely the total polymer concentration, on the drying method efficiency and the properties of the electrospun product. The formulation was based on a mixture of hydrophilic polymers poloxamer 188 and polyethylene oxide in the weight ratio of 1:1, which is acceptable for potential parenteral application. We showed that the total polymer concentration of prior-drying samples is closely related to their viscosity and conductivity, also affecting the morphology of the electrospun product. However, the change in morphology of the electrospun product does not affect the efficiency of SPION reconstitution from the electrospun product. Regardless of the morphology, the electrospun product is not in powder form and is therefore safer to handle compared to powder nanoformulations. The optimal total polymer concentration in the prior-drying SPION dispersion, which enables the formation of an easily dispersible electrospun product with high SPION-loading (65% (w/w)) and fibrillar morphology, was shown to be 4.2% (w/v).
RESUMO
The conjugation of photoactive benzophenone with diphenylalanine yielded a self-assembling photocatalyst that was probed in the E â Z photoisomerisation of stilbene derivatives.
Assuntos
Dipeptídeos , Nanoestruturas , Fenilalanina , BenzofenonasRESUMO
We studied inflammatory and oxidative stress-related parameters and cytotoxic response of human umbilical vein endothelial cells (HUVEC) to a 24 h treatment with milled particles simulating debris involved in sandblasting of orthopedic implants (OI). We used different abrasives (corundum-(Al2O3), used corundum retrieved from removed OI (u. Al2O3), and zirconia/silica composite (ZrO2/SiO2)). Morphological changes were observed by scanning electron microscopy (SEM). Concentration of Interleukins IL-6 and IL-1ß and Tumor Necrosis Factor α (TNF)-α was assessed by enzyme-linked immunosorbent assay (ELISA). Activity of Cholinesterase (ChE) and Glutathione S-transferase (GST) was measured by spectrophotometry. Reactive oxygen species (ROS), lipid droplets (LD) and apoptosis were measured by flow cytometry (FCM). Detachment of the cells from glass and budding of the cell membrane did not differ in the treated and untreated control cells. Increased concentration of IL-1ß and of IL-6 was found after treatment with all tested particle types, indicating inflammatory response of the treated cells. Increased ChE activity was found after treatment with u. Al2O3 and ZrO2/SiO2. Increased GST activity was found after treatment with ZrO2/SiO2. Increased LD quantity but not ROS quantity was found after treatment with u. Al2O3. No cytotoxicity was detected after treatment with u. Al2O3. The tested materials in concentrations added to in vitro cell lines were found non-toxic but bioactive and therefore prone to induce a response of the human body to OI.
RESUMO
D-Ser(tBu)-L-Phe-L-Trp is described as a self-assembling tripeptide that yields nanofibrillar hydrogels at physiological conditions (phosphate buffer at pH 7.4). The peptide is characterized by several spectroscopic methods, such as circular dichroism and fluorescence, oscillatory rheometry, and transmission electron microscopy. Single-crystal X-ray diffraction reveals supramolecular packing into water-bound channels and allows the visualization of the intermolecular interactions holding together peptide stacks.
Assuntos
Hidrogéis , Peptídeos , Hidrogéis/química , Peptídeos/química , Microscopia Eletrônica de Transmissão , Cristalografia por Raios X , Dicroísmo Circular , ÁguaRESUMO
Conventional treatments for chronic wounds are often ineffective, thus new therapeutic approaches are needed, such as the delivery of immunomodulatory drugs that can reduce inflammation, restore immune cell function, and facilitate tissue regeneration. A potential drug for such an approach is simvastatin, which has major drawbacks including poor solubility and chemical instability. With the aim of developing a dressing for wound healing, simvastatin and an antioxidant were incorporated into alginate/poly(ethylene oxide) nanofibers by green electrospinning without the use of organic solvents, thanks to their prior encapsulation into liposomes. The composite liposome-nanofiber formulations exhibited fibrillar morphology (160-312 nm) and unprecedentedly high phospholipid and drug content (76%). Transmission electron microscopy revealed dried liposomes as bright ellipsoidal spots homogeneously distributed over the nanofibers. After nanofiber hydration, the liposomes reconstituted in two size populations (~140 and ~435 nm), as revealed by cutting-edge MADLS® analysis. Lastly, in vitro assays demonstrated that composite liposome-nanofiber formulations are superior to liposomal formulations due to a better safety profile in keratinocytes and peripheral blood mononuclear cells. Furthermore, both formulations exhibited similarly advantageous immunomodulatory effects, measured as decreased inflammation in vitro. A synergistic combination of the two nanodelivery systems shows promise for the development of efficient dressings for chronic wound treatment.
RESUMO
The effects of the shape anisotropy of nanoparticles on cellular uptake is still poorly understood due to challenges in the synthesis of anisotropic magnetic nanoparticles of the same composition. Here, we design and synthesize spherical magnetic nanoparticles and their anisotropic assemblies, namely magnetic nanochains (length â¼800 nm). Then, nanoparticle shape anisotropy is investigated on urothelial cells in vitro. Although both shapes of nanomaterials reveal biocompatibility, we havefound significant differences in the extent of their intracellular accumulation. Contrary to spherical particles, anisotropic nanochains preferentially accumulate in cancer cells as confirmed by inductively coupled plasma (ICP) analysis, indicating that control of the nanoparticle shape geometry governs cell-type-selective intracellular uptake and accumulation.
Assuntos
Nanopartículas de Magnetita , Nanopartículas , Anisotropia , MagnetismoRESUMO
Localized surface plasmon resonance (LSPR) is the cause of the photo-thermal effect observed in topological insulator (TI) bismuth selenide (Bi2Se3) nanoparticles. These plasmonic properties, which are thought to be caused by its particular topological surface state (TSS), make the material interesting for application in the field of medical diagnosis and therapy. However, to be applied, the nanoparticles have to be coated with a protective surface layer, which prevents agglomeration and dissolution in the physiological medium. In this work, we investigated the possibility of using silica as a biocompatible coating for Bi2Se3 nanoparticles, instead of the commonly used ethylene-glycol, which, as is presented in this work, is not biocompatible and alters/masks the optical properties of TI. We successfully prepared Bi2Se3 nanoparticles coated with different silica layer thicknesses. Such nanoparticles, except those with a thick, ≈200 nm silica layer, retained their optical properties. Compared to ethylene-glycol coated nanoparticles, these silica coated nanoparticles displayed an improved photo-thermal conversion, which increased with the increasing thickness of the silica layer. To reach the desired temperatures, a 10-100 times lower concentration of photo-thermal nanoparticles was needed. In vitro experiments on erythrocytes and HeLa cells showed that, unlike ethylene glycol coated nanoparticles, silica coated nanoparticles are biocompatible.
RESUMO
Supramolecular hydrogels obtained from the self-organization of simple peptides, such as tripeptides, are attractive soft materials. Their viscoelastic properties can be enhanced through the inclusion of carbon nanomaterials (CNMs), although their presence can also hinder self-assembly, thus requiring investigation of the compatibility of CNMs with peptide supramolecular organization. In this work, we compared single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) as nanostructured additives for a tripeptide hydrogel, revealing superior performance by the latter. Several spectroscopic techniques, as well as thermogravimetric analyses, microscopy, and rheology data, provide details to elucidate the structure and behavior of nanocomposite hydrogels of this kind.
RESUMO
One of the key technological challenges in the development of iron-oxide-based magnetic nanoparticles (MNPs) is their long-term physical stability in colloidal dispersions. This can be improved by their transformation into a dry form. Here, we introduce electrospinning as a drying method for ethanol-based and water-based MNP dispersions, which enables the preparation of high-loaded dry MNP products. The obtained easily dispersible electrospun product contained up to 50 % (w/w) of MNPs, homogeneously distributed in the fibrillar structure, which is much more compared to the products of currently available methods for drying MNP dispersions. The polymers used as building blocks of nanofibers, namely poloxamer 188 and polyethylene oxide, improved the tolerance of MNPs to high ionic strength dispersion medium and thus enhanced the short-term physical stability of MNP dispersions after reconstitution. The dry product was stable for up to 1 month at room temperature and relative humidity up to 70 %. It was in the form of a nanofiber mat, which prevented the aerosolization of MNPs and their unintentional ambient exposure. Therefore, the electrospun product with MNPs is expected to be a safer dry formulation of MNPs than the nanoparticulate powders, which are usually the final products of the conventional drying methods.
Assuntos
Nanopartículas de Magnetita , Nanofibras , Nanopartículas de Magnetita/química , Nanofibras/química , Polímeros/química , Composição de Medicamentos/métodos , Polietilenoglicóis/químicaRESUMO
Superparamagnetic iron oxide nanoparticles (SPIONs) have great potential for use in medicine, but they may cause side effects due to oxidative stress. In our study, we investigated the effects of silica-coated SPIONs on endothelial cells and whether oleic acid (OA) can protect the cells from their harmful effects. We used viability assays, flow cytometry, infrared spectroscopy, fluorescence microscopy, and transmission electron microscopy. Our results show that silica-coated SPIONs are internalized by endothelial cells, where they increase the amount of reactive oxygen species (ROS) and cause cell death. Exposure to silica-coated SPIONs induced accumulation of lipid droplets (LD) that was not dependent on diacylglycerol acyltransferase (DGAT)-mediated LD biogenesis, suggesting that silica-coated SPIONs suppress LD degradation. Addition of exogenous OA promoted LD biogenesis and reduced SPION-dependent increases in oxidative stress and cell death. However, exogenous OA protected cells from SPION-induced cell damage even in the presence of DGAT inhibitors, implying that LDs are not required for the protective effect of exogenous OA. The molecular phenotype of the cells determined by Fourier transform infrared spectroscopy confirmed the destructive effect of silica-coated SPIONs and the ameliorative role of OA in the case of oxidative stress. Thus, exogenous OA protects endothelial cells from SPION-induced oxidative stress and cell death independent of its incorporation into triglycerides.