88 research outputs found
An insight into biomolecules for the treatment of skin infectious diseases
In assigning priorities, skin infectious diseases are frequently classified as minor when
compared to infectious diseases of high mortality rates, such as tuberculosis or HIV. However, skin
infections are amongst the most common and prevalent diseases worldwide. Elderly individuals
present an increased susceptibility to skin infections, which may develop atypical signs and symptoms
or even complicate pre-existing chronic disorders. When the skin fails to correct or inhibit the
action of certain pathogenic microorganisms, biomolecules endowed with antimicrobial features are
frequently administered topically or systemically to assist or treat such conditions. (1) Antibiotics,
(2) antimicrobial peptides, or (3) natural extracts display important features that can actively inhibit
the propagation of these pathogens and prevent the evolution of infectious diseases. This review
highlights the properties and mechanisms of action of these biomolecules, emphasizing their effects
on the most prevalent and difficult to treat skin infections caused by pathogenic bacteria, fungi, and
viruses. The versatility of biomolecules’ actions, their symbiotic effects with skin cells and other
inherent antimicrobial components, and their target-directed signatures are also explored hereFoundation for Science and Technology of Portugal (FCT),
FEDER via Portugal 2020 Competitive Factors Operational Program (POCI), and the Government of Portugal (OE) for supporting the projects PTDC/CTM-TEX/28074/2017 (POCI-01-0145-FEDER028074) and UID/CTM/00264/202
Frontiers in antimicrobial biomaterials
[Excerpt] Biomaterials can be used as implantable devices or drug delivery platforms, which
have significant impacts on the patient’s quality of life. Indeed, every year, a substantial
number of new biomaterials and scaffolding systems are engineered and introduced in
the biomedical field, with increased health benefits observed, as reported by Spalek et al.
[1]. However, their long-term use can be threatened by the adhesion and proliferation of
microorganisms, which can interact and form biofilms, or by the formation of fibrosis and
consequent triggered cytotoxic responses. Pathogenic microorganisms may cause local infections and lead to implant failures
Green antimicrobials
[Excerpt] In the last couple of years, the awareness of climate change and high pollution levels
have raised our sense of ecological responsibility. Pharmaceutical industries play a major
role in these issues; as such, alternatives must be found. New environmentally friendly
approaches to deal with the growing concern associated with antimicrobial-resistant bacteria are also in great demand. The excessive consumption and misuse of these agents have
accelerated the rise of such pathogens responsible for compromising global health—not
only the health of humans, but also the health of all living systems.This research was funded by the Portuguese Foundation for Science and Technology (FCT)
via grant UID/CTM/00264/2020 of 2C2T Strategic Project 2020–2023. H.P.F. also acknowledges the
FCT for Auxiliary Researcher contract 2021.02720.CEECIND
Mg63 osteoblast-like cells response to surface modified commercially pure titanium
Dissertação de mestrado em Biomedical Engineering (área de especilaização em Biomaterials, Biomechanics and Rehabilitation)The interaction between implanted materials and surrounding tissue,
osseointegration, is the critical factor for the successful restoration and reconstruction of
damaged body parts. Since the biological response is strongly influenced by the
properties of the biomaterials outermost layer, after few minutes of contact a protein
film will be formed on the implant surface and its stability will determine the long-term
success of the implant. Attending to all the problems related to implantation, it has
becoming essential to analyze in detail the response of the human body to different and
modified biomaterials surfaces.
In this project, the interaction between the osteoblasts and the commercially pure
titanium (CP Ti) was investigated. CP Ti samples were modified by anodic treatment,
with calcium (Ca) and phosphorus (P), and all phases involved in the tissue restoration
were carefully followed and examined. In parallel, tribocorrosion tests were conducted
on that samples, prior to osteoblasts culture, to verify the influence of the chemical and
physical properties of the surface on their development and with that extrapolate the
possible response of the human body after some time of implantation.
As a result, it was proven that anodic treatment can be effective and can incite
osteoblasts MG63 development on titanium surfaces. The adhesion and morphologic
tests showed that, even after small periods of time, these cells found their way to
interact with the surface and create a bond, which can prevail for longest periods of
culture (proliferation). Regarding osteoblasts MG63 differentiation, the results showed a
very distinct line of evolution, exposing some important traces of the osteoblasts
maturation, with a small but perceptive improvement in the levels of calcium and
phosphate, proportioned by the bioactive properties of the anodic film. On the
tribocorroded surfaces, it was clear the cells adhesion and progression, although in a
slower rate compared to the regular surfaces. Additionally, through this test, it was also
verified the MG63 osteoblasts preference for rougher surfaces.
For future investigations, however, the anodic treatment conditions should be
changed, starting for instance in the electrolyte composition, in order to achieve a much
more significant improvement in the cells behaviour.A interacção entre o implante e o tecido subjacente, osteointegração, é o factor
crítico para uma restauração e reconstrução de regiões do corpo danificadas bem
sucedida. Uma vez que a resposta biológica é fortemente influenciada pelas
propriedades da camada mais externa dos biomateriais, após alguns minutos em
contacto um filme proteico é formado à superfície do biomaterial e a sua estabilidade irá
determinar o sucesso a longo prazo do implante. Tendo em consideração todos os
problemas associados à colocação de um implante, a análise cuidadosa e detalhada da
resposta do corpo humano a alterações na superfície dos biomateriais tem-se tornado
essencial.
Neste projecto, a interacção entre os osteoblastos e o titânio comercialmente
puro (Ti CP) foi investigada. A superfície das amostras de Ti CP foi modificada por
tratamento anódico, com cálcio (Ca) e fósforo (P), e todas as fases envolvidas na
restauração do tecido ósseo foram meticulosamente seguidas e examinadas. Em
paralelo, testes tribocorrosivos foram conduzidos sobre as amostras, num período prévio
à cultura celular, de modo a verificar a influência das propriedades físicas e químicas da
superfície no desenvolvimento das células ósseas. Com isto pretendeu-se inferir acerca
da resposta do corpo humano após algum tempo de implantação.
A partir dos resultados foi provada a eficácia do tratamento anódico e a sua
influência positiva sobre o desenvolvimento dos osteoblastos MG63 em superfícies de
Ti. Os ensaios de adesão e morfologia comprovaram que, mesmo após curtos períodos
de tempo em contacto, as células são capazes de interagir e criar fortes ligações, capazes
de prevalecer por longos períodos de cultura (proliferação). Relativamente à
diferenciação celular dos osteoblasts MG63, os resultados demonstraram, com grande
detalhe, a evolução do desenvolvimento osteoblástico, sendo, ainda, perceptiva uma
pequena melhoria nos níveis de cálcio e fosfato proporcionado pelas propriedades
bioactivas do filme anódico. Quanto às superfícies tribologicamente modificadas, foi
evidente a adesão e progressão celular, contudo de uma forma mais lenta do que nas
superfícies consideradas normais. Além disso, foi comprovada a preferência dos
osteoblastos MG63 por superfícies mais rugosas. Porém, em investigações futuras, as condições do tratamento anódico deverão
ser mudados, começando por exemplo pela composição do electrólito. Deste modo,
melhorias mais significativas no comportamento celular poderão ser alcançadas
Electrospun polymeric dressings functionalized with antimicrobial peptides and collagen type I for enhanced wound healing
Modern wound dressings combine medical textiles with active compounds that
stimulate wound healing while protecting against infection. Electrospun wound dressings have
been extensively studied and the electrospinning technique recognized as an efficient approach
for the production of nanoscale fibrous mats. The unique diverse function and architecture of
antimicrobial peptides (AMPs) has attracted considerable attention as a tool for the design of
new anti-infective drugs. Functionalizing electrospun wound dressings with these AMPs is
nowadays being researched. In the present work, we explore these new systems by highlighting
the most important characteristics of electropsun wound dressings, revealing the importance of
AMPs to wound healing, and the methods available to functionalize the electrospun mats with
these molecules. The combined therapeutic potential of collagen type I and these AMP
functionalized dressings will be highlighted as well; the significance of these new strategies for
the future of wound healing will be clarified.FCT -Fuel Cell Technologies Program(POCI-01-0145-FEDER-007136)info:eu-repo/semantics/publishedVersio
Antimicrobial peptides in infected wounds
Wound healing is a fundamental process to re-establish tissue integrity. Microbial infections, however, may hinder this process and compromise our health. The increasing resistance of microorganisms colonizing infections to conventional antibiotics has raised many concerns. Hence, new treatment options have been researched and new biomolecules uncovered. As known, multicellular organisms are endowed with an arsenal of host-defense molecules, the Antimicrobial Peptides (AMPs) that fight microbial invaders and modulate the host’s immune response. In recent years, research has been focused on the development of such molecules with lower toxicity and improved activity compared to their endogenous counterparts for potential applications
in wound healing. The present work offers a review over AMPs involved in wound healing and used against infected wounds, their potentialities and limitations, and highlights their mode of action. The challenges with the use of AMPs and the current strategies to prevent those challenges are also enumerated
Extraction of cellulose-based polymers from textile wastes
[Excert] The extraction and exploration of cellulose-based polymers is an exciting area of
research. For many years, wood (especially from bleached kraft wood pulp) was
considered the main source of cellulosic compounds because of its abundance in nature
[1,2]. However, in the past decade, researchers have been devoted to finding alternatives
to extract cellulose from byproducts of agricultural crops and/or textile wastes, both
highly available at a very reduced raw material cost.This research was funded by the Portuguese Foundation for Science and Technology (FCT) grants PTDC/CTMTEX/28074/2017, PTDC/CTM TEX/28295/2017 and UID/CTM/00264/2021
Recent advances in fiber-hydrogel composites for wound healing and drug delivery systems
In the last decades, much research has been done to fasten wound healing and target-direct drug delivery. Hydrogel-based scaffolds have been a recurrent solution in both cases, with some reaching already the market, even though their mechanical stability remains a challenge. To overcome this limitation, reinforcement of hydrogels with fibers has been explored. The structural resemblance of fiber–hydrogel composites to natural tissues has been a driving force for the optimization and exploration of these systems in biomedicine. Indeed, the combination of hydrogel-forming techniques and fiber spinning approaches has been crucial in the development of scaffolding systems with improved mechanical strength and medicinal properties. In this review, a comprehensive overview of the recently developed fiber–hydrogel composite strategies for wound healing and drug delivery is provided. The methodologies employed in fiber and hydrogel formation are also highlighted, together with the most compatible polymer combinations, as well as drug incorporation approaches creating stimuli-sensitive and triggered drug release towards an enhanced host response.Authors acknowledge the Portuguese Foundation for Science and Technology
(FCT), FEDER funds by means of Portugal 2020 Competitive Factors Operational Program (POCI),
and the Portuguese Government (OE) for funding the project PEPTEX with reference PTDC/CTM‐
TEX/28074/2017 (POCI‐01‐0145‐FEDER‐028074). The authors also acknowledge project
UID/CTM/00264/2021 of the Centre for Textile Science and Technology (2C2T), funded by national
funds through FCT/MCTES
Assessing textile antiviral properties
Apresentação efetuada no MicroSummit 2022, no Porto, Portugal, 202
Synergistically enhanced stability of laccase immobilized on synthesized silver nanoparticles with water-soluble polymers
"In Press, Accepted Manuscript, Available online 12 March 2017"Silver nanoparticles (AgNPs) were synthesized by citrate reduction method in the presence of polymers, poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA) and chitosan, used as stabilizing agents, and an oxidoreductase enzyme, laccase (Lac), with the goal of expanding the NPs antimicrobial action.
AgNPs were characterized by UV-visible spectrometry, dynamic light scattering and transmission electron microscopy. As protecting agents, PEG and PVA promoted the formation of spherical uniformly-shaped, small-sized, monodispersed AgNPs (≈ 20 nm). High Mw polymers were established as most effective in producing small-sized NPs. Chitosan's viscosity led to the formation of aggregates. Despite the decrease in Lac activity registered for the hybrid formulation, AgNPs-polymer-Lac, a significant augment in stability over time (up to 13 days, at 50 °C) was observed. This novel formulation displays improved synergistic performance over AgNPs-Lac or polymer-Lac conjugates, since in the former the Lac activity becomes residual at the end of 3 days. By enabling many ionic interactions, chitosan restricted the mass transfer between Lac and substrate and, thus, inhibited the enzymatic activity.
These hybrid nanocomposites made up of inorganic NPs, organic polymers and immobilized antimicrobial oxidoreductive enzymes represent a new class of materials with improved synergistic performance. Moreover, the Lac and the AgNPs different antimicrobial action, both in time and mechanism, may also constitute a new alternative to reduce the probability of developing resistance-associated mutations.This work was funded by Portuguese Foundation for Science and TechnologyFCT/MCTES (PIDDAC) and co-financed by European funds (FEDER) through the PT2020 program, research projectM-ERA-NET/0006/2014. A. Zille and H. P. Felgueiras also acknowledge funding from FCT within the scope of the project POCI-01-0145-FEDER-007136 and UID/CTM/00264
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