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1.
Brain Sci ; 14(1)2024 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-38248297

RESUMO

Glioblastoma (GBM) is a primary malignant tumor of the central nervous system responsible for the most deaths among patients with primary brain tumors. Current therapies for GBM are not effective, with the average survival of GBM patients after diagnosis being limited to a few months. Chemotherapy is difficult in this case due to the heterogeneity of GBM and the high efficacy of the blood-brain barrier, which makes drug absorption into the brain extremely difficult. In a previous study, 3',4',3,4,5-trimethoxychalcone (MB) showed antiproliferative and anti-invasion activities toward GBM cells. Polymersomes (PMs) are an attractive, new type of nanoparticle for drug administration, due to their high stability, enhanced circulation time, biodegradability, and sustained drug release. In the present study, different MB formulations, PEG2000-PCL and PEG5000-PCL, were synthesized, characterized, and compared in terms of 14-day stability and in vitro cytotoxicity (hCMEC/D3 and U-373 MG).

2.
Life (Basel) ; 14(1)2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38255746

RESUMO

Glioblastoma (GBM) is the most common and deadly primary malignant brain tumor. Current therapies are insufficient, and survival for individuals diagnosed with GBM is limited to a few months. New GBM treatments are urgent. Polymeric nanoparticles (PNs) can increase the circulation time of a drug in the brain capillaries. Polymersomes (PMs) are PNs that have been described as having attractive characteristics, mainly due to their stability, prolonged circulation period, biodegradability, their ability to sustain the release of drugs, and the possibility of surface functionalization. In this work, a poly(ethylene glycol)-ε-caprolactone (PEG-PCL) copolymer was synthesized and PMs were prepared and loaded with an hydrolytic instable compound, previously synthesized by our research team, the 3,6-bis(2,3,4,6-tetra-O-acetyl-ß-glucopyranosyl)xanthone (XGAc), with promising cytotoxicity on glioblastoma cells (U-373 MG) but also on healthy cerebral endothelial cells (hCMEC/D3). The prepared PMs were spherical particles with uniform morphology and similar sizes (mean diameter of 200 nm) and were stable in aqueous suspension. The encapsulation of XGAc in PMs (80% encapsulation efficacy) protected the healthy endothelial cells from the cytotoxic effects of this compound, while maintaining cytotoxicity for the glioblastoma cell line U-373 MG. Our studies also showed that the prepared PMs can efficiently release XGAc at intratumoral pHs.

3.
Adv Healthc Mater ; : e2303861, 2023 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-38041539

RESUMO

Responsive magnetic nanomaterials offer significant advantages for innovative therapies, for instance, in cancer treatments that exploit on-demand delivery on alternating magnetic field (AMF) stimulus. In this work, biocompatible magnetic bionanocomposite films are fabricated from chitosan by film casting with incorporation of magnetite nanoparticles (MNPs) produced by facile one pot synthesis. The influence of synthesis conditions and MNP concentration on the films' heating efficiency and heat dissipation are evaluated through spatio-temporal mapping of the surface temperature changes by video-thermography. The cast films have a thickness below 100 µm, and upon exposure to AMF (663 kHz, 12.8 kA m-1 ), induce exceptionally strong heating, reaching a maximum temperature increase of 82 °C within 270 s irradiation. Further, it is demonstrated that the films can serve as substrates that supply heat for multiple hyperthermia scenarios, including: i) non-contact automated heating of cell culture medium, ii) heating of gelatine-based hydrogels of different shapes, and iii) killing of cancerous melanoma cells. The films are versatile components for non-contact stimulus with translational potential in multiple biomedical applications.

4.
Int J Mol Sci ; 24(21)2023 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-37958633

RESUMO

Tuberculosis is an infectious disease caused by the bacterial complex Mycobacterium tuberculosis. Despite the decline in the incidence and mortality of this disease over the years, the emergence of new strains of tuberculosis resistant to existing tuberculostatic drugs is currently one of the largest public health problems. The engineering and development of new drugs is a complex process; therefore, the modification and enhancement of the drugs already marked is a better and faster solution. Ethambutol (ETB) is an antimycobacterial drug used to treat tuberculosis; however, it is highly hygroscopic and is sparingly soluble in water. Therapeutic Deep Eutectic Solvents (THEDESs) are known to improve drug solubility, permeability, and hygroscopicity, among others. In this study, three THEDESs of ETB were synthesized with sucralose, glucose and glycerol and then encapsulated in nanostructured lipid carriers to improve their stability. This work is a proof of concept on the possibility of encapsulating the THEDESs, and results show that the encapsulation of ETB is possible, yielding formulations with a loading capacity superior to 8.5% and able to incorporate THEDESs and not just ETB.


Assuntos
Etambutol , Tuberculose , Humanos , Solventes , Lipossomos , Excipientes
5.
Molecules ; 28(12)2023 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-37375143

RESUMO

In this study, the chemical composition and antioxidant profile of five edible macroalgae, Fucus vesiculosus, Palmaria palmata, Porphyra dioica, Ulva rigida, and Gracilaria gracilis, cultivated in fully controlled closed systems, were determined. Protein, carbohydrates, and fat contents ranged between 12.4% and 41.8%, 27.6% and 42.0%, and 0.1% and 3.4%, respectively. The tested seaweeds presented considerable amounts of Ca, Mg, K, Mn, and Fe, which reinforce their favorable nutritional profile. Regarding their polysaccharide composition, Gracilaria gracilis and Porphyra dioica were rich in sugars common to agar-producing red algae, and Fucus vesiculosus was composed mainly of uronic acids, mannose, and fucose, characteristic of alginate and fucoidans, whereas rhamnose and uronic acid, characteristic of ulvans, predominated in Ulva rigida. Comparatively, the brown F. vesiculosus clearly stood out, presenting a high polysaccharide content rich in fucoidans, and higher total phenolic content and antioxidant scavenging activity, determined by DPPH and ABTS. The remarkable potential of these marine macroalgae makes them excellent ingredients for a wide range of health, food, and industrial applications.


Assuntos
Gracilaria , Rodófitas , Alga Marinha , Ulva , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Alga Marinha/química , Rodófitas/química , Gracilaria/química , Ulva/química , Polissacarídeos/metabolismo
6.
NPJ Biofilms Microbiomes ; 9(1): 39, 2023 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-37328504

RESUMO

Staphylococcus aureus is considered a high priority pathogen by the World Health Organization due to its high prevalence and the potential to form biofilms. Currently, the available treatments for S. aureus biofilm-associated infections do not target the extracellular polymeric substances (EPS) matrix. This matrix is a physical barrier to bactericidal agents, contributing to the increase of antimicrobial tolerance. The present work proposes the development of lipid nanoparticles encapsulating caspofungin (CAS) as a matrix-disruptive nanosystem. The nanoparticles were functionalized with D-amino acids to target the matrix. In a multi-target nano-strategy against S. aureus biofilms, CAS-loaded nanoparticles were combined with a moxifloxacin-loaded nanosystem, as an adjuvant to promote the EPS matrix disruption. In vitro and in vivo studies showed biofilm reduction after combining the two nanosystems. Besides, the combinatory therapy showed no signs of bacterial dissemination into vital organs of mice, while dissemination was observed for the treatment with the free compounds. Additionally, the in vivo biodistribution of the two nanosystems revealed their potential to reach and accumulate in the biofilm region, after intraperitoneal administration. Thus, this nano-strategy based on the encapsulation of matrix-disruptive and antibacterial agents is a promising approach to fight S. aureus biofilms.


Assuntos
Infecções Estafilocócicas , Staphylococcus aureus , Animais , Camundongos , Distribuição Tecidual , Biofilmes , Infecções Estafilocócicas/microbiologia , Antibacterianos/farmacologia , Antibacterianos/química
7.
Biomater Adv ; 151: 213443, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37146526

RESUMO

Photothermal therapy has emerged as a new promising strategy for the management of cancer, either alone or combined with other therapeutics, such as chemotherapy. The use of nanoparticles for multimodal therapy can improve treatment performance and reduce drug doses and associated side effects. Here we propose the development of a novel multifunctional nanosystem based on solid lipid nanoparticles co-loaded with gold nanorods and mitoxantrone and functionalized with folic acid for dual photothermal therapy and chemotherapy of breast cancer. Nanoparticles were produced using an economically affordable method and presented suitable physicochemical properties for tumor passive accumulation. Upon Near-Infrared irradiation (808 nm, 1.7 W cm-2, 5 min), nanoparticles could effectively mediate a temperature increase of >20 °C. Moreover, exposure to light resulted in an enhanced release of Mitoxantrone. Furthermore, nanoparticles were non-hemolytic and well tolerated by healthy cells even at high concentrations. The active targeting strategy was found to be successful, as shown by the greater accumulation of the functionalized nanoparticles in MCF-7 cells. Finally, the combined effects of chemotherapy, light-induced drug release and photothermal therapy significantly enhanced breast cancer cell death. Overall, these results demonstrate that the developed lipid nanosystem is an efficient vehicle for breast cancer multimodal therapy.


Assuntos
Neoplasias da Mama , Nanopartículas , Humanos , Feminino , Neoplasias da Mama/tratamento farmacológico , Mitoxantrona/uso terapêutico , Terapia Fototérmica , Nanopartículas/uso terapêutico , Nanopartículas/química
8.
J Colloid Interface Sci ; 646: 775-783, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37229995

RESUMO

Chitooligosaccharides have been suggested as cholesterol reducing ingredients mostly due to their ability to sequestrate bile salts. The nature of the chitooligosaccharides-bile salts binding is usually linked with the ionic interaction. However, at physiological intestinal pH range (6.4 to 7.4) and considering chitooligosaccharides pKa, they should be mostly uncharged. This highlights that other type of interaction might be of relevance. In this work, aqueous solutions of chitooligosaccharides with an average degree of polymerization of 10 and 90 % deacetylated, were characterized regarding their effect on bile salt sequestration and cholesterol accessibility. Chitooligosaccharides were shown to bind bile salts to a similar extent as the cationic resin colestipol, both decreasing cholesterol accessibility as measured by NMR at pH 7.4. A decrease in the ionic strength leads to an increase in the binding capacity of chitooligosaccharides, in agreement with the involvement of ionic interactions. However, when the pH is decreased to 6.4, the increase in charge of chitooligosaccharides is not followed by a significant increase in bile salt sequestration. This corroborates the involvement of non-ionic interactions, which was further supported by NMR chemical shift analysis and by the negative electrophoretic mobility attained for the bile salt-chitooligosaccharide aggregates at high bile salt concentrations. These results highlight that chitooligosaccharides non-ionic character is a relevant structural feature to aid in the development of hypocholesterolemic ingredients.


Assuntos
Ácidos e Sais Biliares , Colesterol , Colesterol/química , Micelas , Cátions
9.
Mar Drugs ; 21(5)2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37233496

RESUMO

Fucoidan has been reported to present diverse bioactivities, but each extract has specific features from which a particular biological activity, such as immunomodulation, must be confirmed. In this study a commercially available pharmaceutical-grade fucoidan extracted from Fucus vesiculosus, FE, was characterized and its anti-inflammatory potential was investigated. Fucose was the main monosaccharide (90 mol%) present in the studied FE, followed by uronic acids, galactose, and xylose that were present at similar values (3.8-2.4 mol%). FE showed a molecular weight of 70 kDa and a sulfate content of around 10%. The expression of cytokines by mouse bone-marrow-derived macrophages (BMDMs) revealed that the addition of FE upregulated the expression of CD206 and IL-10 by about 28 and 22 fold, respectively, in respect to control. This was corroborated in a stimulated pro-inflammatory situation, with the higher expression (60 fold) of iNOS being almost completely reversed by the addition of FE. FE was also capable of reverse LPS-caused inflammation in an in vivo mouse model, including by reducing macrophage activation by LPS from 41% of positive CD11C to 9% upon fucoidan injection. Taken together, the potential of FE as an anti-inflammatory agent was validated, both in vitro and in vivo.


Assuntos
Fucus , Camundongos , Animais , Lipopolissacarídeos , Polissacarídeos/farmacologia , Citocinas
10.
Plants (Basel) ; 12(6)2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36987012

RESUMO

Fucus vesiculosus is a brown seaweed with applications in the food, pharmaceutic, and cosmetic industries. Among its most valuable bioactive compounds are the pigment fucoxanthin and polysaccharides (e.g., fucoidans). In this study, we profiled the photosynthetic pigments and carbohydrates of F. vesiculosus from six locations along the Ílhavo Channel in the Iberian coastal lagoon of Ria de Aveiro, Portugal. Photosynthetic performance (Fv/Fm), pigment, and carbohydrate concentrations were similar between locations, despite differences in environmental factors, such as salinity and periods of exposure to desiccation. Concentration of total carbohydrates (neutral sugars + uronic acids) averaged 418 mg g-1 dw. Fucose was the second most abundant neutral sugar, with an average concentration of 60.7 mg g-1 dw, indicating a high content of fucoidans. Photosynthetic pigments included chlorophylls a and c, ß,ß-carotene, and the xanthophylls fucoxanthin, violaxanthin, antheraxanthin, and zeaxanthin. Concentrations of fucoxanthin were higher than those reported for most brown macroalgae, averaging 0.58 mg g-1 dw (65% of total carotenoids). This study indicates that F. vesiculosus from Ria de Aveiro is a valuable macroalgal resource for aquaculture companies operating in the region, with considerable potential to yield high-value bioactive compounds.

11.
Mar Drugs ; 21(3)2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36976232

RESUMO

Brown macroalgae are an important source of polysaccharides, mainly fucose-containing sulphated polysaccharides (FCSPs), associated with several biological activities. However, the structural diversity and structure-function relationships for their bioactivities are still undisclosed. Thus, the aim of this work was to characterize the chemical structure of water-soluble Saccharina latissima polysaccharides and evaluate their immunostimulatory and hypocholesterolemic activities, helping to pinpoint a structure-activity relationship. Alginate, laminarans (F1, neutral glucose-rich polysaccharides), and two fractions (F2 and F3) of FCSPs (negatively charged) were studied. Whereas F2 is rich in uronic acids (45 mol%) and fucose (29 mol%), F3 is rich in fucose (59 mol%) and galactose (21 mol%). These two fractions of FCSPs showed immunostimulatory activity on B lymphocytes, which could be associated with the presence of sulphate groups. Only F2 exhibited a significant effect in reductions in in vitro cholesterol's bioaccessibility attributed to the sequestration of bile salts. Therefore, S. latissima FCSPs were shown to have potential as immunostimulatory and hypocholesterolemic functional ingredients, where their content in uronic acids and sulphation seem to be relevant for the bioactive and healthy properties.


Assuntos
Laminaria , Fucose/química , Água , Polissacarídeos/farmacologia , Polissacarídeos/química , Sulfatos , Ácidos Urônicos
12.
Membranes (Basel) ; 13(2)2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36837642

RESUMO

Cationic antimicrobial peptides (CAMPs) offer a promising strategy to counteract bacterial resistance, mostly due to their membrane-targeting activity. W-BP100 is a potent broad-spectrum cecropin-melittin CAMP bearing a single N-terminal Trp, which was previously found to improve its antibacterial activity. W-BP100 has high affinity toward anionic membranes, inducing membrane saturation at low peptide-to-lipid (P/L) ratios and membrane permeabilization, with the unique property of promoting the aggregation of anionic vesicles only at specific P/L ratios. Herein, we aimed to investigate this unusual behavior of W-BP100 by studying its aggregation and fusion properties with negatively-charged large (LUVs) or giant (GUVs) unilamellar vesicles using biophysical tools. Circular dichroism (CD) showed that W-BP100 adopted an α-helical conformation in anionic LUVs, neutralizing its surface charge at the aggregation P/L ratio. Its fusion activity, assessed by Förster resonance energy transfer (FRET) using steady-state fluorescence spectroscopy, occurred mainly at the membrane saturation/aggregation P/L ratio. Confocal microscopy studies confirmed that W-BP100 displays aggregation and detergent-like effects at a critical P/L ratio, above which it induces the formation of new lipid aggregates. Our data suggest that W-BP100 promotes the aggregation and fusion of anionic vesicles at specific P/L ratios, being able to reshape the morphology of GUVs into new lipid structures.

13.
Eur J Pharm Biopharm ; 184: 214-247, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36773725

RESUMO

Cutaneous melanoma (CM) is a multifactorial disease whose treatment still presents challenges: the rapid progression to advanced CM, which leads to frequent recurrences even after surgical excision and, notably, the low response rates and resistance to the available therapies, particularly in the case of unresectable metastatic CM. Thereby, alternative innovative therapeutic approaches for CM continue to be searched. In this review we discuss relevant preclinical research studies, and provide a broad-brush analysis of patents and clinical trials which involve the application of nanotechnology-based delivery systems in CM therapy. Nanodelivery systems have been developed for the delivery of anticancer biomolecules to CM, which can be administered by different routes. Overall, nanosystems could promote technological advances in several therapeutic modalities and can be used in combinatorial therapies. Nevertheless, the results of these preclinical studies have not been translated to clinical applications. Thus, concerted and collaborative research studies involving basic, applied, translational, and clinical scientists need to be performed to allow the development of effective and safe nanomedicines to treat CM.


Assuntos
Melanoma , Neoplasias Cutâneas , Humanos , Neoplasias Cutâneas/patologia , Sistemas de Liberação de Fármacos por Nanopartículas , Administração Cutânea
14.
Foods ; 12(3)2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36766042

RESUMO

Coccolithophore microalgae, such as Emiliania huxleyi (EHUX) and Chrysotila pseudoroscoffensis (CP), are composed of calcium carbonate (CaCO3) and contain bioactive compounds that can be explored to produce sustainable food packaging. In this study, for the first time, these microalgae were incorporated as fillers in starch-based films, envisioning the development of biodegradable and bioactive materials for food packaging applications. The films were obtained by solvent casting using different proportions of the filler (2.5, 5, 10, and 20%, w/w). For comparison, commercial CaCO3, used as filler in the plastic industry, was also tested. The incorporation of CaCO3 and microalgae (EHUX or CP) made the films significantly less rigid, decreasing Young's modulus up to 4.7-fold. Moreover, the incorporation of microalgae hydrophobic compounds as lipids turned the surface hydrophobic (water contact angles > 90°). Contrary to what was observed with commercial CaCO3, the films prepared with microalgae exhibited antioxidant activity, increasing from 0.9% (control) up to 60.4% (EHUX 20%) of ABTS radical inhibition. Overall, the introduction of microalgae biomass improved hydrophobicity and antioxidant capacity of starch-based films. These findings should be considered for further research using coccolithophores to produce active and sustainable food packaging material.

15.
Biochim Biophys Acta Biomembr ; 1865(3): 184115, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36603803

RESUMO

There is a growing need for alternatives to target and treat bacterial infection. Thus, the present work aims to develop and optimize the production of PEGylated magnetoliposomes (MLPs@PEG), by encapsulating superparamagnetic iron oxide nanoparticles (SPIONs) within fusogenic liposomes. A Box-Behnken design was applied to modulate size distribution variables, using lipid concentration, SPIONs amount and ultrasonication time as independent variables. As a result of the optimization, it was possible to obtain MLPs@PEG with a mean size of 182 nm, with polydispersity index (PDI) of 0.19, and SPIONs encapsulation efficiency (%EE) around 76%. Cytocompatibility assays showed that no toxicity was observed in fibroblasts, for iron concentrations up to 400µg/ml. Also, for safe lipid and iron concentrations, no hemolytic effect was detected. The fusogenicity of the nanosystems was first evaluated through lipid mixing assays, based on Förster resonance energy transfer (FRET), using liposomal membrane models, mimicking bacterial cytoplasmic membrane and eukaryotic plasma membrane. It was shown that the hybrid nanosystems preferentially interact with the bacterial membrane model. Confocal microscopy and fluorescence lifetime measurements, using giant unilamellar vesicles (GUVs), validated these results. Overall, the developed hybrid nanosystem may represent an efficient drug delivery system with improved targetability for bacterial membrane.


Assuntos
Sistemas de Liberação de Medicamentos , Lipossomas Unilamelares , Ferro , Lipídeos
16.
Molecules ; 28(1)2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36615600

RESUMO

Chlorella vulgaris is a green microalga with a high chlorophyll content, representing a valuable source of green pigments for food applications. As the application of whole biomass can promote an unpleasant fish-like flavor, the use of chlorophyll extract can overcome this drawback. However, chlorophylls tend to easily degrade when out of the chloroplasts, decreasing their potential as a food ingredient. Thus, to study the suitable conditions for isolated chlorophylls preservation, in this work, the influence of temperature (4 to 60 °C), light (dark or 24 h photoperiod), alkaline conditions (with or without aqueous NaOH addition), and modified atmosphere (air or argon atmosphere) on the stability of the color in ethanolic solutions obtained from C. vulgaris were studied. The loss of green color with temperature followed the first-order kinetics, with an activation energy of 74 kJ/mol. Below 28 °C and dark conditions were suitable to preserve isolated chlorophylls. The addition of NaOH and an inert argon-rich atmosphere did not exhibit a statistically positive effect on color preservation. In the case study, cooked cold rice was colored to be used in sushi. The color remained stable for up to 3 days at 4 °C. Therefore, this work showed that C. vulgaris chlorophylls could be preserved in ethanolic solutions at room or lower temperatures when protected from light, allowing them to obtain a suitable natural food ingredient to color foodstuffs.


Assuntos
Chlorella vulgaris , Ingredientes de Alimentos , Chlorella vulgaris/metabolismo , Argônio , Hidróxido de Sódio , Clorofila/metabolismo
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 287(Pt 2): 122118, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36401918

RESUMO

A fast, simple, and reliable method for determination of metformin was developed by coupling surface-enhanced Raman spectroscopy (SERS) with chemometric methods. This relayed on the utilization of a portable Raman spectrometer and of citrate stabilized gold nanoparticles (AuNPs) as substrate, to carry out the measurement of SERS scattering signals, thus assuring improved sensitivity. The obtained datasets were analysed using principal component analysis (PCA) and partial least squares (PLS) regression. Upon optimization of the PLS model, in terms of latent variables, spectral region and pre-processing techniques, RMSECV and R2CV values of 0.42 mg/L and 0.94, respectively, were obtained. The optimized PLS regression model was further validated with the projection of commercial pharmaceutical samples, providing good results in terms of R2P (0.97), RE (4.54 %) and analytical sensitivity (2.13 mg/L).


Assuntos
Nanopartículas Metálicas , Metformina , Análise Espectral Raman , Ouro , Quimiometria
18.
Int J Biol Macromol ; 226: 1021-1030, 2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36436608

RESUMO

Calcium carbonate (CaCO3) is used as a filler to improve the stiffness and processability of plastics at low cost. However, its high density limits the quantity to be used. In this work, the feasibility of using starch consolidation of eggshells-derived CaCO3 (ES) to develop lightweight fillers for low density polyethylene (LDPE)-based materials was studied. Starch, recovered from potato by-products, was combined with ES, gelatinized, dried, and milled as a fine powder. The obtained ES/starch-based particles were then compounded with LDPE and their influence on chromatic, mechanical, morphological, and density properties of mold injected LDPE-based materials was studied. Commercially available CaCO3 (COM) was used as control. ES/starch particles were 18 times less dense than the commercially available CaCO3 (2.62 g cm-3). When incorporated into LDPE-based formulations, ES/starch originated brownish materials with lower density (1.18 g cm-3) and higher stiffness (542 MPa of Young's modulus) than those produced with the COM sample (1.33 g cm-3 of density; 221 MPa of Young's modulus). Therefore, starch consolidation of ES revealed to be a promising approach to develop lightweight fillers able to provide stiffness and color to LDPE-based plastics, while valorizing biomolecules-rich by-products.


Assuntos
Plásticos , Polietileno , Carbonato de Cálcio , Módulo de Elasticidade , Amido
19.
Pharmaceutics ; 14(12)2022 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-36559239

RESUMO

The major risk factor associated with the development of gastric cancer is chronic infection with Helicobacter pylori. The available treatments, based on a cocktail of antibiotics, fail in up to 40% of patients and disrupt their gut microbiota. The potential of blank nanostructured lipid carriers (NLC) for H. pylori eradication was previously demonstrated by us. However, the effect of NLC charge, size and protein corona on H. pylori-specific bactericidal activity herein studied was unknown at that time. All developed NLC formulations proved bactericidal against H. pylori. Although cationic NLC had 10-fold higher bactericidal activity than anionic NLC, they lacked specificity, since Lactobacillus acidophilus was also affected. Anionic NLC achieved complete clearance in both H. pylori morphologies (rod- and coccoid-shape) by inducing alterations in bacteria membranes and the cytoplasm, as visualized by transmission electron microscopy (TEM). The presence of an NLC protein corona, composed of 93% albumin, was confirmed by mass spectrometry. This protein corona delayed the bactericidal activity of anionic NLC against H. pylori and hindered NLC activity against Escherichia coli. Overall, these results sustain the use of NLC as a promising antibiotic-free strategy targeting H. pylori.

20.
Humanit Soc Sci Commun ; 9(1): 434, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36530543

RESUMO

While studies suggested adverse impacts of COVID-19 on scientific outputs and work routines for scientists, more evidence is required to understand detailed obstacles challenging scientists' work and productivity during the pandemic, including how different people are affected (e.g., by gender). This online survey-based thematic analysis investigated how the pandemic affected scientists' perception of scientific and academic productivity in the science, technology, engineering, and mathematics (STEM) and medicine fields. The analysis examined if inequitable changes in duties and responsibilities for caregiving for children, family, and/or households exist between scientists who are mothers compared to scientists who are fathers or non-parents. The survey collected data from 2548 survey responses in six languages across 132 countries. Results indicate that many scientists suffered from delays and restrictions on research activities and administrations due to the lockdown of institutions, as well as increased workloads from adapting to online teaching environment. Caregiving responsibility for children and family increased, which compromised time for academic efforts, especially due to the temporary shutdown of social supports. Higher percentages of female parent participants than male parent participants expressed such increased burdens indicating unequal divisions of caregiving between women and men. A range of physical and mental health issues was identified mainly due to overworking and isolation. Despite numerous obstacles, some participants reported advantages during the pandemic including the efficiency of online teaching, increased funding for COVID-related research, application of alternative research methodologies, and fluidity of the workday from not commuting. Findings imply the need for rapid institutional support to aid various academic activities and diminish gender inequity in career development among academicians, highlighting how crisis can exacerbate existing inequalities.

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