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