Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 44
Filtrar
1.
Nature ; 563(7733): 681-685, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30487614

RESUMO

The mid-latitude westerly winds of the Southern Hemisphere play a central role in the global climate system via Southern Ocean upwelling1, carbon exchange with the deep ocean2, Agulhas leakage (transport of Indian Ocean waters into the Atlantic)3 and possibly Antarctic ice-sheet stability4. Meridional shifts of the Southern Hemisphere westerly winds have been hypothesized to occur5,6 in parallel with the well-documented shifts of the intertropical convergence zone7 in response to Dansgaard-Oeschger (DO) events- abrupt North Atlantic climate change events of the last ice age. Shifting moisture pathways to West Antarctica8 are consistent with this view but may represent a Pacific teleconnection pattern forced from the tropics9. The full response of the Southern Hemisphere atmospheric circulation to the DO cycle and its impact on Antarctic temperature remain unclear10. Here we use five ice cores synchronized via volcanic markers to show that the Antarctic temperature response to the DO cycle can be understood as the superposition of two modes: a spatially homogeneous oceanic 'bipolar seesaw' mode that lags behind Northern Hemisphere climate by about 200 years, and a spatially heterogeneous atmospheric mode that is synchronous with abrupt events in the Northern Hemisphere. Temperature anomalies of the atmospheric mode are similar to those associated with present-day Southern Annular Mode variability, rather than the Pacific-South American pattern. Moreover, deuterium-excess records suggest a zonally coherent migration of the Southern Hemisphere westerly winds over all ocean basins in phase with Northern Hemisphere climate. Our work provides a simple conceptual framework for understanding circum-Antarctic temperature variations forced by abrupt Northern Hemisphere climate change. We provide observational evidence of abrupt shifts in the Southern Hemisphere westerly winds, which have previously documented1-3 ramifications for global ocean circulation and atmospheric carbon dioxide. These coupled changes highlight the necessity of a global, rather than a purely North Atlantic, perspective on the DO cycle.

2.
Angew Chem Int Ed Engl ; : e202410791, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38949226

RESUMO

Aurothiomalate (AuTM) is an FDA-approved antiarthritic gold drug with unique anticancer properties. To enhance its anticancer activity, we prepared a bioconjugate with human apoferritin (HuHf) by attaching some AuTM moieties to surface protein residues. The reaction of apoferritin with excess AuTM yielded a single adduct, that was characterized by ESI MS and ICP-OES analysis, using three mutant ferritins and trypsinization experiments. The adduct contains ~3 gold atoms per ferritin subunit, arranged in a small cluster bound to Cys90 and Cys102. MD simulations provide a plausible structural model for the cluster. The adduct was evaluated for its pharmacological properties and was found to be significantly more cytotoxic than free AuTM against A2780 cancer cells mainly due to higher gold uptake. NMR-metabolomics showed that AuTM bound to HuHf and free AuTM induced qualitatively similar changes in treated cancer cells, indicating that the effects on cell metabolism are approximately the same, in agreement with independent biochemical experiments. In conclusion, we have demonstrated here that a molecularly precise bioconjugate formed between AuTM and HuHf exhibits anticancer properties far superior to the free drug, while retaining its key mechanistic features. Evidence is provided that human ferritin can serve as an excellent carrier for this metallodrug.

3.
Environ Sci Technol ; 56(16): 11189-11198, 2022 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-35878000

RESUMO

Atmospheric aerosols are important drivers of Arctic climate change through aerosol-cloud-climate interactions. However, large uncertainties remain on the sources and processes controlling particle numbers in both fine and coarse modes. Here, we applied a receptor model and an explainable machine learning technique to understand the sources and drivers of particle numbers from 10 nm to 20 µm in Svalbard. Nucleation, biogenic, secondary, anthropogenic, mineral dust, sea salt and blowing snow aerosols and their major environmental drivers were identified. Our results show that the monthly variations in particles are highly size/source dependent and regulated by meteorology. Secondary and nucleation aerosols are the largest contributors to potential cloud condensation nuclei (CCN, particle number with a diameter larger than 40 nm as a proxy) in the Arctic. Nonlinear responses to temperature were found for biogenic, local dust particles and potential CCN, highlighting the importance of melting sea ice and snow. These results indicate that the aerosol factors will respond to rapid Arctic warming differently and in a nonlinear fashion.


Assuntos
Poluentes Atmosféricos , Aerossóis/análise , Poluentes Atmosféricos/análise , Poeira/análise , Aprendizado de Máquina , Tamanho da Partícula , Svalbard
4.
Biometals ; 34(4): 867-879, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33907910

RESUMO

Chloro(triethylphosphine)gold(I), (Et3PAuCl hereafter), is an Auranofin (AF)-related compound showing very similar biological and pharmacological properties. Like AF, Et3PAuCl exhibits potent antiproliferative properties in vitro toward a variety of cancer cell lines and is a promising anticancer drug candidate. We wondered whether Et3PAuCl encapsulation might lead to an improved pharmacological profile also considering the likely reduction of unwanted side-reactions that are responsible for adverse effects and for drug inactivation. Et3PAuCl was encapsulated in biocompatible PLGA-PEG nanoparticles (NPs) and the new formulation evaluated in colorectal HCT-116 cancer cells in comparison to the free gold complex. Notably, encapsulated Et3PAuCl (nano-Et3PAuCl hereafter) mostly retains the cellular properties of the free gold complex and elicits even greater cytotoxic effects in colorectal cancer (CRC) cells, mediated by apoptosis and autophagy. Moreover, a remarkable inhibition of two crucial signaling pathways, i.e. ERK and AKT, by nano-Et3PAuCl, was clearly documented. The implications of these findings are discussed.


Assuntos
Antineoplásicos/farmacologia , Neoplasias Colorretais/tratamento farmacológico , Nanopartículas/química , Compostos Organoáuricos/farmacologia , Poliésteres/química , Polietilenoglicóis/química , Antineoplásicos/síntese química , Antineoplásicos/química , Cápsulas , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Compostos Organoáuricos/síntese química , Compostos Organoáuricos/química , Células Tumorais Cultivadas
5.
Sensors (Basel) ; 20(7)2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32235527

RESUMO

The Arctic is an important natural laboratory that is extremely sensitive to climatic changes and its monitoring is, therefore, of great importance. Due to the environmental extremes it is often hard to deploy sensors and observations are limited to a few sparse observation points limiting the spatial and temporal coverage of the Arctic measurement. Given these constraints the possibility of deploying a rugged network of low-cost sensors remains an interesting and convenient option. The present work validates for the first time a low-cost sensor array (AIRQino) for monitoring basic meteorological parameters and atmospheric composition in the Arctic (air temperature, relative humidity, particulate matter, and CO2). AIRQino was deployed for one year in the Svalbard archipelago and its outputs compared with reference sensors. Results show good agreement with the reference meteorological parameters (air temperature (T) and relative humidity (RH)) with correlation coefficients above 0.8 and small absolute errors (≈1 °C for temperature and ≈6% for RH). Particulate matter (PM) low-cost sensors show a good linearity (r2 ≈ 0.8) and small absolute errors for both PM2.5 and PM10 (≈1 µg m-3 for PM2.5 and ≈3 µg m-3 for PM10), while overall accuracy is impacted both by the unknown composition of the local aerosol, and by high humidity conditions likely generating hygroscopic effects. CO2 exhibits a satisfying agreement with r2 around 0.70 and an absolute error of ≈23 mg m-3. Overall these results, coupled with an excellent data coverage and scarce need of maintenance make the AIRQino or similar devices integrations an interesting tool for future extended sensor networks also in the Arctic environment.

6.
Beilstein J Org Chem ; 16: 2272-2281, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32983271

RESUMO

Mechanochemistry is an emerging and reliable alternative to conventional solution (batch) synthesis of complex molecules under green and solvent-free conditions. In this regard, we report here on the conjugation of a dextran polysaccharide with a fluorescent probe, a phenylboronic acid (PBA)-functionalized boron dipyrromethene (BODIPY) applying the ball milling approach. The ball milling formation of boron esters between PBA BODIPY and dextran proved to be more efficient in terms of reaction time, amount of reactants, and labelling degree compared to the corresponding solution-based synthetic route. PBA-BODIPY dextran assembles into nanoparticles of around 200 nm by hydrophobic interactions. The resulting PBA-BODIPY dextran nanoparticles retain an apolar interior as proved by pyrene fluorescence, suitable for the encapsulation of hydrophobic drugs with high biocompatibility while remaining fluorescent.

7.
Br J Cancer ; 118(2): 200-212, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29161243

RESUMO

BACKGROUND: Platinum-based drugs such as Cisplatin are commonly employed for cancer treatment. Despite an initial therapeutic response, Cisplatin treatment often results in the development of chemoresistance. To identify novel approaches to overcome Cisplatin resistance, we tested Cisplatin in combination with K+ channel modulators on colorectal cancer (CRC) cells. METHODS: The functional expression of Ca2+-activated (KCa3.1, also known as KCNN4) and voltage-dependent (Kv11.1, also known as KCNH2 or hERG1) K+ channels was determined in two CRC cell lines (HCT-116 and HCT-8) by molecular and electrophysiological techniques. Cisplatin and several K+ channel modulators were tested in vitro for their action on K+ currents, cell vitality, apoptosis, cell cycle, proliferation, intracellular signalling and Platinum uptake. These effects were also analysed in a mouse model mimicking Cisplatin resistance. RESULTS: Cisplatin-resistant CRC cells expressed higher levels of KCa3.1 and Kv11.1 channels, compared with Cisplatin-sensitive CRC cells. In resistant cells, KCa3.1 activators (SKA-31) and Kv11.1 inhibitors (E4031) had a synergistic action with Cisplatin in triggering apoptosis and inhibiting proliferation. The effect was maximal when KCa3.1 activation and Kv11.1 inhibition were combined. In fact, similar results were produced by Riluzole, which is able to both activate KCa3.1 and inhibit Kv11.1. Cisplatin uptake into resistant cells depended on KCa3.1 channel activity, as it was potentiated by KCa3.1 activators. Kv11.1 blockade led to increased KCa3.1 expression and thereby stimulated Cisplatin uptake. Finally, the combined administration of a KCa3.1 activator and a Kv11.1 inhibitor also overcame Cisplatin resistance in vivo. CONCLUSIONS: As Riluzole, an activator of KCa3.1 and inhibitor of Kv11.1 channels, is in clinical use, our results suggest that this compound may be useful in the clinic to improve Cisplatin efficacy and overcome Cisplatin resistance in CRC.


Assuntos
Cisplatino/farmacologia , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/metabolismo , Canal de Potássio ERG1/antagonistas & inibidores , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Animais , Apoptose/efeitos dos fármacos , Benzotiazóis/farmacologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/farmacocinética , Neoplasias Colorretais/patologia , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Canal de Potássio ERG1/metabolismo , Células HCT116 , Células HT29 , Humanos , Concentração Inibidora 50 , Camundongos , Bloqueadores dos Canais de Potássio/farmacologia , Pirazóis/farmacologia , Riluzol/farmacologia
8.
Biochim Biophys Acta Gen Subj ; 1862(9): 1980-1987, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29842905

RESUMO

BACKGROUND: The CIA2A protein, in complex with CIAO1, has been proposed to be exclusively implicated in the maturation of cytosolic aconitase. However, how the CIA2A-CIAO1 complex generates active aconitase is still unknown and the available structural information has not provided any crucial insights into the molecular function of CIA2A. METHODS: In this work we have characterized the Fe/S cluster binding properties of CIA2A and of the CIA2A-CIAO1 complex via NMR, UV - vis absorption and EPR spectroscopies and we have investigated how the Fe/S cluster is transferred to inactive aconitase/IRP1 protein. RESULTS: We found that an heterotrimeric species formed by two molecules of CIA2A and one of CIAO1 can bind one [4Fe-4S] cluster and that residue Cys90 of CIA2A is one of the cluster ligand. The holo trimeric complex is able to transfer the [4Fe-4S] cluster to apo-IRP1 thus generating the active form of aconitase. CONCLUSIONS AND GENERAL SIGNIFICANCE: These findings, which highlight a functional role for CIA2A-CIAO1 complex in aconitase maturation, raises a broad interest and can have a high impact on the community studying metal trafficking and iron­sulfur protein biogenesis. The present study can provide solid bases for further investigation of the molecular mechanisms involving also other CIA machinery proteins.


Assuntos
Proteínas de Transporte/metabolismo , Proteína 1 Reguladora do Ferro/metabolismo , Ferro/metabolismo , Metalochaperonas/metabolismo , Sulfetos/metabolismo , Proteínas de Transporte/química , Proteínas de Transporte/genética , Citosol , Humanos , Ferro/química , Proteína 1 Reguladora do Ferro/química , Proteína 1 Reguladora do Ferro/genética , Metalochaperonas/química , Metalochaperonas/genética , Metaloproteínas , Mutagênese Sítio-Dirigida , Mutação , Ligação Proteica , Conformação Proteica , Sulfetos/química
9.
Biometals ; 29(3): 535-42, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27086032

RESUMO

The dibromido analogue of cisplatin, cis-PtBr2(NH3)2 (cisPtBr2 hereafter), has been prepared and characterised. Its solution behaviour in standard phosphate buffer, at pH 7.4, was investigated spectrophotometrically and found to reproduce quite closely that of cisplatin; indeed, progressive sequential release of the two halide ligands typically occurs as in the case of cisplatin, with a roughly similar kinetics. Afterward, patterns of reactivity toward model proteins and standard ctDNA were explored and the nature of the resulting interactions elucidated. The antiproliferative properties were then evaluated in four representative cancer cell lines, namely A549 (human lung cancer), HCT116 (human colon cancer), IGROV-1 (human ovarian cancer) and FLG 29.1 (human acute myeloid leukaemia). Cytotoxic properties in line with those of cisplatin were highlighted. From these studies an overall chemical and biological profile emerges for cisPtBr2 closely matching that of cisplatin; the few slight, but meaningful differences that were underscored might be advantageously exploited for clinical application.


Assuntos
Antineoplásicos/farmacologia , Brometos/farmacologia , Cisplatino/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Brometos/química , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Proteínas Filagrinas , Células HCT116 , Humanos , Ligantes , Estrutura Molecular , Relação Estrutura-Atividade , Células Tumorais Cultivadas
10.
Anal Chem ; 87(22): 11441-7, 2015 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-26494022

RESUMO

Recently, the increasing interest in the understanding of global climatic changes and on natural processes related to climate yielded the development and improvement of new analytical methods for the analysis of environmental samples. The determination of trace chemical species is a useful tool in paleoclimatology, and the techniques for the analysis of ice cores have evolved during the past few years from laborious measurements on discrete samples to continuous techniques allowing higher temporal resolution, higher sensitivity and, above all, higher throughput. Two fast ion chromatographic (FIC) methods are presented. The first method was able to measure Cl(-), NO3(-) and SO4(2-) in a melter-based continuous flow system separating the three analytes in just 1 min. The second method (called Ultra-FIC) was able to perform a single chromatographic analysis in just 30 s and the resulting sampling resolution was 1.0 cm with a typical melting rate of 4.0 cm min(-1). Both methods combine the accuracy, precision, and low detection limits of ion chromatography with the enhanced speed and high depth resolution of continuous melting systems. Both methods have been tested and validated with the analysis of several hundred meters of different ice cores. In particular, the Ultra-FIC method was used to reconstruct the high-resolution SO4(2-) profile of the last 10,000 years for the EDML ice core, allowing the counting of the annual layers, which represents a key point in dating these kind of natural archives.

11.
Environ Sci Technol ; 48(3): 1795-802, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24397469

RESUMO

Ice cores are widely used to reconstruct past changes of the climate system. For instance, the ice core record of numerous water-soluble and insoluble chemical species that are trapped in snow and ice offer the possibility to investigate past changes of various key compounds present in the atmosphere (i.e., aerosol, reactive gases). We developed a new method for the quantitative determination of fluoride in ice cores at sub-µg L(-1) levels by coupling a flow injection analysis technique with a fast ion chromatography separation based on the "heart cut" column switching technology. Sensitivity, linear range (up to 60 µg L(-1)), reproducibility, and detection limit (0.02 µg L(-1)) were evaluated for the new method. This method was successfully applied to the analysis of fluoride at trace levels in more than 450 recent snow samples collected during the 1998-1999 International Trans-Antarctica Scientific Expedition traverse in East Antarctica at sites located between 170 and 850 km from the coastline.


Assuntos
Cromatografia/métodos , Fluoretos/análise , Gelo/análise , Regiões Antárticas , Atmosfera/química , Clima , Reprodutibilidade dos Testes , Neve , Água/química
12.
Nanoscale Horiz ; 9(7): 1211-1218, 2024 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-38775782

RESUMO

A hybrid cellulose-based programmable nanoplatform for applications in precision radiation oncology is described. Here, sugar heads work as tumor targeting moieties and steer the precise delivery of radiosensitizers, i.e. gold nanoparticles (AuNPs) into triple negative breast cancer (TNBC) cells. This "Trojan horse" approach promotes a specific and massive accumulation of radiosensitizers in TNBC cells, thus avoiding the fast turnover of small-sized AuNPs and the need for high doses of AuNPs for treatment. Application of X-rays resulted in a significant increase of the therapeutic effect while delivering the same dose, showing the possibility to use roughly half dose of X-rays to obtain the same radiotoxicity effect. These data suggest that this hybrid nanoplatform acts as a promising tool for applications in enhancing cancer radiotherapy effects with lower doses of X-rays.


Assuntos
Celulose , Ouro , Nanopartículas Metálicas , Radiossensibilizantes , Neoplasias de Mama Triplo Negativas , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Radiossensibilizantes/química , Ouro/química , Celulose/química , Humanos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/uso terapêutico , Nanopartículas Metálicas/efeitos da radiação , Linhagem Celular Tumoral , Feminino , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Nanopartículas/química , Sobrevivência Celular/efeitos dos fármacos
13.
Chemosphere ; 329: 138674, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37054845

RESUMO

Starting from 1952 C.E. more than 540 atmospheric nuclear weapons tests (NWT) were conducted in different locations of the Earth. This lead to the injection of about 2.8 t of 239Pu in the environment, roughly corresponding to a total 239Pu radioactivity of 6.5 PBq. A semiquantitative ICP-MS method was used to measure this isotope in an ice core drilled in Dome C (East Antarctica). The age scale for the ice core studied in this work was built by searching for well-known volcanic signatures and synchronising these sulfate spikes with established ice core chronologies. The reconstructed plutonium deposition history was compared with previously published NWT records, pointing out an overall agreement. The geographical location of the tests was found to be an important parameter strongly affecting the concentration of 239Pu on the Antarctic ice sheet. Despite the low yield of the tests conducted in the 1970s, we highlight their important role in the deposition of radioactivity in Antarctica due to the relative closeness of the testing sites.


Assuntos
Armas Nucleares , Plutônio , Cinza Radioativa , Cinza Radioativa/análise , Regiões Antárticas , Plutônio/análise , Camada de Gelo
14.
J Colloid Interface Sci ; 640: 100-109, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-36842416

RESUMO

Although promising for biomedicine, the clinical translation of inorganic nanoparticles (NPs) is limited by low biocompatibility and stability in biological fluids. A common strategy to circumvent this drawback consists in disguising the active inorganic core with a lipid bilayer coating, reminiscent of the structure of the cell membrane to redefine the chemical and biological identity of NPs. While recent reports introduced membrane-coating procedures for NPs, a robust and accessible method to quantify the integrity of the bilayer coverage is not yet available. To fill this gap, we prepared SiO2 nanoparticles (SiO2NPs) with different membrane coverage degrees and monitored their interaction with AuNPs by combining microscopic, scattering, and optical techniques. The membrane-coating on SiO2NPs induces spontaneous clustering of AuNPs, whose extent depends on the coating integrity. Remarkably, we discovered a linear correlation between the membrane coverage and a spectral descriptor for the AuNPs' plasmonic resonance, spanning a wide range of coating yields. These results provide a fast and cost-effective assay to monitor the compatibilization of NPs with biological environments, essential for bench tests and scale-up. In addition, we introduce a robust and scalable method to prepare SiO2NPs/AuNPs hybrids through spontaneous self-assembly, with a high-fidelity structural control mediated by a lipid bilayer.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Bicamadas Lipídicas/química , Nanopartículas Metálicas/química , Ouro/química , Dióxido de Silício/química , Biomimética , Nanopartículas/química
15.
Sci Total Environ ; 879: 163070, 2023 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-36990237

RESUMO

The study of airborne chemical markers is crucial for identifying sources of aerosols, and their atmospheric processes of transport and transformation. The investigation of free amino acids and their differentiation between the L- and D- enantiomers are even more important to understand their sources and atmospheric fate. Aerosol samples were collected with a high-volume sampler with cascade impactor at Mario Zucchelli Station (MZS) on the coast of the Ross Sea (Antarctica) for two summer campaigns (2018/19 and 2019/20). The total mean concentration of free amino acids in PM10 was 4 ± 2 pmol m-3 for both campaigns and most of free amino acids were distributed in fine particles. The coarse mode of airborne D-Alanine and dimethylsufoniopropionate in seawater showed a similar trend during both Antarctic campaigns. Thus, the study of D/L Ala ratio in fine, coarse and PM10 fractions indicated the microlayer as the local source. This paper demonstrated that free amino acids follow the trend of DMS and MSA release occurred in the Ross Sea, confirming their applicability as markers for phytoplankton bloom also in paleoclimatic studies.

16.
Nanoscale Horiz ; 8(6): 776-782, 2023 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-36951189

RESUMO

Cellulose nanocrystal and gold nanoparticles are assembled, in a unique way, to yield a novel modular glyconanomaterial whose surface is then easily engineered with one or two different headgroups, by exploiting a robust click chemistry route. We demonstrate the potential of this approach by conjugating monosaccharide headgroups to the glyconanomaterial and show that the sugars retain their binding capability to C-type lectin receptors, as also directly visualized by cryo-TEM.


Assuntos
Nanopartículas Metálicas , Nanopartículas Metálicas/química , Ouro/química , Celulose/química , Química Click , Lectinas Tipo C
17.
ACS Appl Bio Mater ; 6(2): 483-493, 2023 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-36651801

RESUMO

A nanodelivery system based on palladium nanoparticles (PdNP) and cisplatin (CisPt) was developed by physisorption of the drug onto the PdNP synthesized via a green redox process, using d-glucose and polyvinylpyrrolidone (PVP) as reducing and stabilizing/capping agents, respectively. UV-vis analysis and H2-evolution measurements were carried out to prove the nanoparticles' capability to act as bimodal theranostic nanomedicine, i.e., having both plasmonic and photocatalytic properties. XPS, XRD, and TEM allowed light to be shed on the chemical composition and morphology of the PdNP. The analysis of the UV-visible spectra evidenced plasmonic peak changes for the hybrid nanoparticle-drug assembly (Pd@CisPt), which pointed to a significant interaction of CisPt with the NP surface. The drug loading was quantitatively estimated by ICP-OES measurements, while DLS and AFM confirmed the strong association of the drug with the nanoparticle surface. The test of SOD-like activity in a cell-free environment proved the maintenance of the antioxidant capability of PdNP also in the Pd@CisPt systems. Finally, Pd@CisPt tested in prostate cancer cells (PC-3 line) unveiled the antitumoral action of the developed nanomedicine, related to reactive oxygen species (ROS) generation, with a condition of protein misfolding/unfolding and DNA damage, as evidenced by cytotoxicity and MitoSOX assays, as well as Raman microspectroscopy, respectively. Cell imaging by confocal microscopy evidenced cellular uptake of the nanoparticles, as well as dynamic processes of copper ion accumulation at the level of subcellular compartments. Finally, cell migration studies upon treatment with Pd@CisPt evidenced a tunable response between the inhibitory effect of CisPt and the enhanced rate of cell migration for the metal NP alone, which pointed out the promising potential of the developed theranostic nanomedicine in tissue regeneration.


Assuntos
Antineoplásicos , Nanopartículas Metálicas , Masculino , Humanos , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Antineoplásicos/química , Nanopartículas Metálicas/uso terapêutico , Nanopartículas Metálicas/química , Nanomedicina Teranóstica/métodos , Paládio/farmacologia , Paládio/química , Cisplatino/química
18.
Nanomaterials (Basel) ; 13(10)2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37242002

RESUMO

The increasing resistance of bacteria to conventional antibiotics represents a severe global emergency for human health. The broad-spectrum antibacterial activity of silver has been known for a long time, and silver at the nanoscale shows enhanced antibacterial activity. This has prompted research into the development of silver-based nanomaterials for applications in clinical settings. In this work, the synthesis of three different silver nanoparticles (AgNPs) hybrids using both organic and inorganic supports with intrinsic antibacterial properties is described. The tuning of the AgNPs' shape and size according to the type of bioactive support was also investigated. Specifically, the commercially available sulfated cellulose nanocrystal (CNC), the salicylic acid functionalized reduced graphene oxide (rGO-SA), and the commercially available titanium dioxide (TiO2) were chosen as organic (CNC, rGO-SA) and inorganic (TiO2) supports. Then, the antimicrobial activity of the AgNP composites was assessed on clinically relevant multi-drug-resistant bacteria and the fungus Candida albicans. The results show how the formation of Ag nanoparticles on the selected supports provides the resulting composite materials with an effective antibacterial activity.

19.
J Hazard Mater ; 424(Pt C): 126661, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-34315635

RESUMO

The recovery and conversion of Extracellular Polymeric Substances (EPS) from sewage sludge into bio-based commodities might improve the economics and environmental sustainability of wastewater treatment. This contribution explores the application of EPS from anammox granular waste sludge as biosorbent for the removal of heavy metals, specifically lead, copper, nickel, and zinc. Adsorption capacities equivalent or higher than well-established adsorbent media emerged from single-metal biosorption studies (up to 84.9, 52.8, 21.7 and 7.4 mg/gTSEPS for Pb2+, Cu2+, Ni2+ and Zn2+, respectively). Combining spectroscopic techniques, a mechanistic hypothesis for metal biosorption, based on a combination of electrostatic interaction, ion exchange, complexation, and precipitation, was proposed. The adsorption mechanisms of extracted EPS and non-extracted EPS in the native biomass were indirectly compared by means of single-metal biosorption studies performed with pristine granules (adsorbing up to 103.7, 36.1, 48.2 and 49.8 mg/gTSgranules of Pb2+, Cu2+, Ni2+, and Zn2+, respectively). In comparison with pristine anammox granules, EPS showed lower adsorption capacities except for copper and different adsorption pathways as postulated based on the adsorption data interpretation via theoretical models. The multi-metal biosorption tests excluded significant competitions among different heavy metals for the EPS binding sites, thus opening further scenarios for the treatment of complex wastewaters.

20.
ACS Appl Mater Interfaces ; 14(5): 7471-7485, 2022 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-35089689

RESUMO

Bronze artifacts constitute a fundamental portion of Cultural Heritage, but effective methodologies for the removal of corrosion layers, such as those produced by the "bronze disease", are currently missing. We propose the formulation and application of novel poly(2-hydroxyethyl methacrylate) (pHEMA) networks semi-interpenetrated (SIPN) with poly(acrylic acid) (PAA) to achieve enhanced capture of copper ions and removal of corrosion products. The pHEMA/PAA SIPNs were designed to improve previous pHEMA/poly(vinylpyrrolidone) (PVP) networks, taking advantage of the chelating ability of pH-responsive carboxylic groups in PAA. Increasing the pH ionizes carboxyls, increases the porosity in pHEMA/PAA, and leads to the co-presence of enol and enolate forms of vinylpyrrolidone (VP), changing the macroporosity and decreasing the mesh size in pHEMA/PVP. The ion-matrix interaction is stronger in pHEMA/PAA, where the process occurs through an initial diffusion-limited step followed by diffusion in smaller pores or adsorption by less available sites. In pHEMA/PVP, the uptake is probably controlled by adsorption as expected, considering the porogen role of PVP in the network. Upon application of the SIPNs loaded with tetraethylenpentamine (TEPA) onto corroded bronze, copper oxychlorides dissolve and migrate inside the gels, where Cu(II) ions form ternary complexes with TEPA and carboxylates in PAA or carbonyls in PVP. The removal of oxychlorides is more effective and faster for pHEMA/PAA than its /PVP counterpart. The selective action of the gels preserved the cuprite layers that are needed to passivate bronze against corrosion, and the pH-responsive behavior of pHEMA/PAA allows full control of the uptake and release of the Cu(II)-TEPA complex, making these systems appealing in several fields even beyond Cultural Heritage conservation (e.g., drug delivery, wastewater treatment, agricultural industry, and food chemistry).

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA