90 research outputs found
Nanoparticle synthesis and their integration into polymer-based fibers for biomedical applications
The potential of nanoparticles as effective drug delivery systems combined with the
versatility of fibers has led to the development of new and improved strategies to help in the
diagnosis and treatment of diseases. Nanoparticles have extraordinary characteristics that are helpful
in several applications, including wound dressings, microbial balance approaches, tissue regeneration,
and cancer treatment. Owing to their large surface area, tailor-ability, and persistent diameter, fibers
are also used for wound dressings, tissue engineering, controlled drug delivery, and protective
clothing. The combination of nanoparticles with fibers has the power to generate delivery systems
that have enhanced performance over the individual architectures. This review aims at illustrating the
main possibilities and trends of fibers functionalized with nanoparticles, focusing on inorganic and
organic nanoparticles and polymer-based fibers. Emphasis on the recent progress in the fabrication
procedures of several types of nanoparticles and in the description of the most used polymers to
produce fibers has been undertaken, along with the bioactivity of such alliances in several biomedical
applications. To finish, future perspectives of nanoparticles incorporated within polymer-based fibers
for clinical use are presented and discussed, thus showcasing relevant paths to follow for enhanced
success in the field.This research was funded by the Portuguese Foundation for Science and Technology (FCT) via
grants UIDP/00264/2020 of 2C2T Strategic Project 2020–2023 and project PTDC/CTMTEX/28074/2017.
This project has been funded by a Research Grant (2022) from the European Society of Clinical
Microbiology and Infectious Diseases (ESCMID) to J.C.A., J.M.D. and C.S.M. also acknowledge FCT
for PhD grants 2020.07387.BD and 2020.08547.BD, respectively, and H.P.F. for auxiliary researcher
contract 2021.02720.CEECIND
Vigilância da Tuberculose nos Profissionais de Saúde como contributo na erradicação de uma Pandemia
A Tuberculose é uma doença infeciosa causada pelo Mycobacterium tuberculosis que,
apesar do tratamento disponível, constitui uma causa de morbimortalidade global
significativa. Pode atingir qualquer órgão, mas afeta principalmente o pulmão, sendo a
via aérea, pela inalação de aerossóis ou microgotículas respiratórias contaminadas, a
principal forma de infeção. O esforço global nas últimas décadas para um diagnóstico
precoce e instituição de tratamento adequado permitiram retirar a Tuberculose das dez
principais causas de mortalidade global, em 2019. A incidência mundial média é de dez
milhões, provavelmente subestimada, configurando uma pandemia frequentemente
esquecida que, contrariamente a outras doenças infeciosas, aumentou a sua incidência
enquanto doença profissional.info:eu-repo/semantics/publishedVersio
Morphological changes in Bombyx Mori silk gland and gut, in association with the feeding of iron oxide nanoparticles
The Bombyx mori silkworm is very important econom-
ically and is a model for several studies. The larval life of silkworms is
divided into five instars. The 5th instar is the longest, where the larvae
show maximum food consumption and growth. The silk is produced
in a paired gland composed of glandular epithelium and a lumen.
Food digestion occurs in the midgut, represented by a folded
columnar monolayered epithelium, which includes goblet cells and
stem cells in a basal lamina. We aimed to investigate the influence
of concentrations of iron oxide nanoparticles (IONPs) in food on
the silk gland and midgut morphology
Bioactivity of chitosan-based particles loaded with plant-derived extracts for biomedical applications: emphasis on antimicrobial fiber-based systems
Marine-derived chitosan (CS) is a cationic polysaccharide widely studied for its bioactivity, which is mostly attached to its primary amine groups. CS is able to neutralize reactive oxygen species (ROS) from the microenvironments in which it is integrated, consequently reducing cell-induced oxidative stress. It also acts as a bacterial peripheral layer hindering nutrient intake and interacting with negatively charged outer cellular components, which lead to an increase in the cell permeability or to its lysis. Its biocompatibility, biodegradability, ease of processability (particularly in mild conditions), and chemical versatility has fueled CS study as a valuable matrix component of bioactive small-scaled organic drug-delivery systems, with current research also showcasing CS's potential within tridimensional sponges, hydrogels and sutures, blended films, nanofiber sheets and fabric coatings. On the other hand, renewable plant-derived extracts are here emphasized, given their potential as eco-friendly radical scavengers, microbicidal agents, or alternatives to antibiotics, considering that most of the latter have induced bacterial resistance because of excessive and/or inappropriate use. Loading them into small-scaled particles potentiates a strong and sustained bioactivity, and a controlled release, using lower doses of bioactive compounds. A pH-triggered release, dependent on CS's protonation/deprotonation of its amine groups, has been the most explored stimulus for that control. However, the use of CS derivatives, crosslinking agents, and/or additional stabilization processes is enabling slower release rates, following extract diffusion from the particle matrix, which can find major applicability in fiber-based systems within ROS-enriched microenvironments and/or spiked with microbes. Research on this is still in its infancy. Yet, the few published studies have already revealed that the composition, along with an adequate drug release rate, has an important role in controlling an existing infection, forming new tissue, and successfully closing a wound. A bioactive finishing of textiles has also been promoting high particle infiltration, superior washing durability, and biological response.FCT. Portuguese Foundation for Science and Technology
(FCT), FEDER funds by means of Portugal 2020 Competitive Factors Operational Program (POCI)
and the Portuguese Government (OE), grant number PTDC/CTMTEX/28074/2017 (POCI-01-0145-
FEDER-028074). Authors also acknowledge project UID/CTM/00264/2021 of Centre for Textile
Science and Technology (2C2T), funded by national funds through FCT/MCTES. J.D. and C.S.M. also
acknowledge FCT for PhD grants 2020.07387.BD and 2020.08547.BD, respectivel
Optimization of ultrasound-assisted extraction of bioactive compounds from Pelvetia canaliculata to sunflower oil
In this study, Pelvetia canaliculata L. macroalga, collected from the Atlantic Portuguese coast,
was used as a source of bioactive compounds, mostly antioxidants, to incorporate them in sunflower
oil with the aim of increasing its biological value and oxidative stability. The lyophilized alga was
added to the oil, and ultrasound-assisted extraction (UAE) was performed. Algae concentration
and UAE time varied following a central composite rotatable design (CCRD) to optimize extraction
conditions. The following parameters were analyzed in the oils: oxidation products, acidity, color,
chlorophyll pigments, carotenoids, flavonoids, total phenolic content, antioxidant activity by DPPH
(2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assays, and sensory
analysis. Extraction conditions did not affect the acidity and the amount of oxidation products in
the oil. Chlorophylls and carotenoid contents increased with algae concentration, while flavonoid
extraction did not depend on algae content or UAE time. Total phenolics in the oil were highly
related only to FRAP antioxidant activity. Storage experiments of supplemented oil (12.5% algae;
20 min UAE) were carried out under accelerated oxidation conditions at 60 C/12 days. Antioxidant
activity (FRAP) of supplemented oil was 6-fold higher than the value of non-supplemented oil. Final
samples retained 40% of their initial antioxidant activity. The presence of algae extracts contributed
to the increased oxidative stability of sunflower oilinfo:eu-repo/semantics/publishedVersio
Active flexible films for food packaging: a review
Active food packaging is a dynamic area where the scientific community and industry have been trying to find new strategies to produce innovative packaging that is economically viable and compatible with conventional production processes. The materials used to develop active packaging can be organized into scavenging and emitting materials, and based on organic and inorganic materials. However, the incorporation of these materials in polymer-based flexible packaging is not always straightforward. The challenges to be faced are mainly related to active agents’ sensitivity to high temperatures or difficulties in dispersing them in the high viscosity polymer matrix. This review provides an overview of methodologies and processes used in the production of active packaging, particularly for the production of active flexible films at the industrial level. The direct incorporation of active agents in polymer films is presented, focusing on the processing conditions and their effect on the active agent, and final application of the packaging material. Moreover, the incorporation of active agents by coating technologies and supercritical impregnation are presented. Finally, the use of carriers to help the incorporation of active agents and several methodologies is discussed. This review aims to guide academic and industrial researchers in the development of active flexible packaging, namely in the selection of the materials, methodologies, and process conditions.Financed by European Regional Development Fund (ERDF), through the
Incentive System to Research and Technological development, within the Portugal2020 Competitiveness and Internationalization Operational Program. IPC researchers acknowledge also funding
by National Funds through FCT-Portuguese Foundation for Science and Technology, References
UIDB/05256/2020 and UIDP/05256/2020
Rheological properties of alkaline activated fly ash used in jet grouting applications
The application of alkaline activated fly ash to soil stabilisation has been recently studied, and although the structural behaviour was adequate, some concerns were raised regarding its apparent viscosity, which proved to be an important issue in jet grouting applications. Therefore, this paper deals with the experimental study of rheology of alkaline activated fly ash-based grouts, namely with: setting time of the freshly mixed grout; fluidity; capillary absorption; shrinkage and expansion behaviour; mass variation during the curing process and density. In order to establish some correlation points with structural performance, uniaxial compression strength (UCS) at 28 days curing was also determined. Six different grout compositions, defined based on Na2O (alkali)/ash and activator / ash ratios, were analysed. The activator was composed of sodium silicate and two different sodium hydroxide concentrations: 10.0 and 12.5 molal. Results show that the fluidity of the grouts correlate very well with UCS, with an increase of the former resulting in a decrease in the latter, which is a concern in jet grouting applications since this parameter controls the velocity of the grout at the nozzle and the soil/grout mixing capability. In terms of porosity, this type of material seems to be less porous than cement-based grouts. However, drying shrinkage values obtained were in general higher than usual for concrete, which is in accordance with results obtained by other researchers.Teixeira Duarte Engenharia e Construções S.A. e Fundação para a Ciência e Tecnologia (FCT
Magnetic responsive cell-based strategies for diagnostics and therapeutics
The potential of magnetically assisted strategies within the remit of cell-based therapies is increasing,
creating new opportunities for biomedical platforms and in the field of tissue engineering and
regenerative medicine. Among the magnetic elements approached for building magnetically
responsive strategies, superparamagnetic iron oxide nanoparticles (SPIONs) represent tunable and
precise tools whose properties can be modelled for detection, diagnosis, targeting and therapy
purposes. The most investigated clinical role of SPIONs is as contrast imaging agents for tracking and
monitoring cells and tissues. Nevertheless, magnetic detection also includes biomarker mapping, cell
labelling and cell/drug targeting to monitor cell events and anticipate the disruption of homeostatic
conditions and the progression of disease. Additionally, the isolation and screening techniques of cell
subsets in heterogeneous populations or of proteins of interest have been explored in a magnetic
sorting context. More recently, SPION-based technologies have been applied to stimulate cell
differentiation and mechanotransduction processes and to transport genetic or drug cargo to study
biological mechanisms and contribute to improved therapies. Magnetically based strategies
significantly contribute to magnetic tissue engineering (magTE), in which magnetically responsive
actuators built from magnetic labelled cells or magnetic functionalized systems can be remotely
controlled and spatially manipulated upon the actuation of an external magnetic field for the delivery
or target of TE solutions. SPION functionalities combined with magnetic responsiveness in
multifactorial magnetically assisted platforms can revolutionize diagnosis and therapeutics, providing
new diagnosis and theranostic tools, encouraging regenerative medicine approaches and having
potential for more effective therapies. This review will address the contribution of SPION-based
technologies as multifunctional tools in boosting magnetically assisted cell-based strategies to explore
diagnostics and tracking solutions for the detection and analysis of pathologies, and to generate
improved treatments and therapies, envisioning precise and customized answers for the management
of numerous diseases.The authors acknowledge the BPD_RL2_DECEMBER_2017fellowship
of AIG and the assistant researcher
contract (RL1) of MTR from the project ‘Accelerating
Tissue Engineering and Personalized Medicine Discoveries
by the Integration of Key Enabling Nanotechnologies,
Marine-derived Biomaterials and Stem Cells’,
supported by Norte Portugal Regional Operational
Programme (NORTE 2020), under the PORTUGAL
2020 Partnership Agreement, through the European
Regional Development Fund (ERDF). The authors also
thank the financial support from FCT for the grant of
MSM (SFRH/BPD/110868/2015).
The authors acknowledge the financial support
from the European Union Framework Programme for
Research and Innovation HORIZON 2020, under the
TEAMING grant agreement no. 739572—the Discoveries
CTR.info:eu-repo/semantics/publishedVersio
Remote triggering of TGF-β/Smad2/3 signaling in human adipose stem cells laden on magnetic scaffolds synergistically promotes tenogenic commitment
Injuries affecting load bearing tendon tissues are a significant clinical burden and efficient treatments are still unmet. Tackling tendon regeneration, tissue engineering strategies aim to develop functional substitutes that recreate native tendon milieu. Tendon mimetic scaffolds capable of remote magnetic responsiveness and functionalized magnetic nanoparticles (MNPs) targeting cellular mechanosensitive receptors are potential instructive tools to mediate mechanotransduction in guiding tenogenic responses. In this work, we combine magnetically responsive scaffolds and targeted Activin A type II receptor in human adipose stem cells (hASCs), under alternating magnetic field (AMF), to synergistically facilitate external control over signal transduction. The combination of remote triggering TGF-β/Smad2/3 using MNPs tagged hASCs, through magnetically actuated scaffolds, stimulates overall expression of tendon related genes and the deposition of tendon related proteins, in comparison to non-stimulated conditions. Moreover, the phosphorylation of Smad2/3 proteins and their nuclear co-localization was also more evident. Overall, biophysical stimuli resulting from magnetic scaffolds and magnetically triggered cells under AMF stimulation modulate the mechanosensing response of hASCs towards tenogenesis, holding therapeutic promise.Authors acknowledge the project “Accelerating tissue engineering and personalized medicine discoveries by the integration of key enabling nanotechnologies, marine-derived biomaterials and stem cells”, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), and the FCT Project MagTT PTDC/CTM-CTM/29930/2017 (POCI-01-0145-FEDER-29930).
Authors acknowledge the HORIZON 2020 for the Achilles Twinning Project No. 810850. Authors also thank the European Research Council COG MagTendon No. 772817 and the ADG DYNACEUTICS No. 789119.
Prof. Bernardo Almeida from Physics Department, University of Minho, is also acknowledged for assisting in the magnetic system assembling.
Authors also acknowledge the INL - International Iberian Nanotechnology Laboratory (Braga, Portugal) for the magnetization analysis
description of the methodological approach
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