Immobilization of biomolecules on chitosan surface for selective recruitment, controlled growth and differentiation of cells from mixed populations

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Functional chitosan microcarriers for selective cell attachment and expansion

The success of many stem cell applications in the biomedical field is highly dependent on the development of reliable techniques either for isolation or selection of specific cell populations with a very high yield and purity.1 In this work we propose the use of chitosan microparticles (μPs) to capture a specific cell type based in the concept of antibody-antigen binding. Our goal was to create new biomaterials capable of selecting within a heterotypic cell suspension, a specific sub-population, and supporting subsequent cell expansion. Such system simultaneously allows the selection and acts as a microcarrier for a specific target, thus reducing cell manipulation and time-consumption

Further evidence of possible therapeutic uses of Sambucus nigra L. extracts by the assessment of the In Vitro and In Vivo anti-inflammatory properties of Its PLGA and PCL-Based Nanoformulations

Sambucus nigra L. is widely used in traditional medicine with different applications. However, confirmative studies are strongly required. This study aimed to assess the biological activities of the S. nigra flower’s extract encapsulated into two different types of nanoparticles for optimizing its properties and producing further evidence of its potential therapeutic uses. Different nanoparticles (poly(lactide-co-glycolide, PLGA) and poly-Ɛ-caprolactone (PCL), both with oleic acid, were prepared by emulsification/solvent diffusion and solvent-displacement methods, respectively. Oleic acid was used as a capping agent. After the nanoparticles’ preparation, they were characterized and the biological activities were studied in terms of collagenase, in vitro and in vivo anti-inflammatory, and in vitro cell viability. Rutin and naringenin were found to be the major phenolic compounds in the studied extract. The encapsulation efficiency was higher than 76% and revealed to have an impact on the release of the extract, mainly for the PLGA. Moreover, biochemical and histopathological analyses confirmed that the extract-loaded PLGA-based nanoparticles displayed the highest anti-inflammatory activity. In addition to supporting the previously reported evidence of potential therapeutic uses of S. nigra, these results could draw the pharmaceutical industry’s interest to the novelty of the nanoproducts.Authors also gratefully acknowledge the Régiefrutas and Fundação para a Ciência e a Tecnologia (FCT) (UIDB/04138/2020, UIDB/00100/2020, UIDP/50017/2020+UIDB/50017/2020) and Portugal 2020 to the Portuguese Mass Spectrometry Network (LISBOA-01-0145-FEDER-402-022125) for financial support. Furthermore, the authors are also grateful to the work supported by the FCT and the Portuguese National and Regional Budget, through CCMAR/Multi/04326/2019 project. Finally, Luísa Custódio was supported by the FCT Scientific Employment Stimulus (CEECIND/00425/2017).info:eu-repo/semantics/publishedVersio

Photo-cross-linked laminarin-based hydrogels for biomedical applications

Laminarin is a low-molecular-weight (<10 kDa) glucan found in brown algae made up of β(1â 3)-glucan with β(1â 6)-branches. This is one of the most abundant carbon sources in the marine ecosystem. Laminarin has been found to possess various biological interesting properties, such as antioxidant and antimicrobial activities. An attractive feature of laminarin is its inherently low viscosity and high solubility in organic and aqueous solvents that facilitate processing. This makes laminarin an appealing material for the development of new hydrogels that can be easily injected through minimally invasive procedures or used for microfabrication of hydrogels. An approach for synthesizing photo-crosslinkable laminarin hydrogels is presented in this work for the first time. Photo-cross-linkable laminarin was prepared by chemical modification with acrylate groups. The synthesized photo-cross-linkable laminarin material provides the basis for the development of a new injectable system for biomedical purposes that could be used alone or with encapsulated cells or biological molecules. The cross-linking of the methacrylated laminarin is straightforward via photoinitiated polymerization. The possibility to control the methacrylation degree of laminarin and to prepare solutions up to at least 15% w/v permits us to obtain hydrogels with tuned and wide range of stiffness and swelling. Furthermore, the encapsulation of human-adipose-derived stem cells encapsulated in the photo-cross-linked hydrogels demonstrated in vitro biocompatibility.European Research Council grant agreement ERC-2012-ADG 20120216-321266 for project ComplexiTE.Portuguese Foundation for Science and Technology (FCT) (fellowship SFRH/BPD/100594/2014

Multilayered hollow tubes as blood vessel substitutes

The available therapies for cardiovascular pathologies often require the replacement of diseased vascular grafts. However, the current blood vessel substitutes are unsuitable for small-diameter blood vessel replacements. Herein, we propose the creation of multilayered hollow tubes as blood vessel substitutes. Hollow tubes were obtained by building-up multilayers of marine-derived polysaccharides (i.e., chitosan and alginate) on sacrificial tubular templates using layer-by-layer technology and template leaching. A cross-linking degree of ≈ 59 % was achieved using genipin, which is reflected in an increase of the mechanical properties and a decrease on the water uptake. To further improve the cell adhesive properties of the multilayers, fibronectin (FN) was immobilized on the surface of the hollow tubes. In vitro biological performance of human umbilical vein endothelial cells (HUVECs) and human aortic smooth muscle cells (HASMCs) were assessed. In addition, to perform the culture of HUVECs on the inner side and the HASMCs on the outer side of the tubes, an in-house developed apparatus was created that allowed us to feed cells with their respective culture medium. The developed hollow tubes showed to be a suitable structure to promote cell adhesion, spreading, and proliferation. It is our belief, that the creation of these functional structures will open a new research field in order to develop innovative multilayered tubular structures for cardiovascular TE applications.The authors acknowledge the financial support by the Portuguese Foundation for Science and Technology (FCT) through the Doctoral and Postdoctoral grants with the reference numbers SFRH/BD/81372/2011 (JMS), SFRH/BPD/100594/2014 (CAC), respectively, cofinanced by the Operational Human Potential Program (POPH) developed under the scope of the National Strategic Reference Framework (QREN) from the European Social Fund (FSE). The authors would also like to acknowledge PTDC/CTMBIO/4706/2014 financed by FCT

Blood Plasma Derivatives for Tissue Engineering and Regenerative Medicine Therapies

To access publisher's full text version of this article click on the hyperlink belowPlatelet-rich plasma (PRP) and its derivatives have been investigated and applied in regenerative medicine. The use of PRP as a supplement of cell culture media has consistently shown to potentiate stem cell proliferation, migration, and differentiation. In addition, the clinical utility of PRP is supported by evidence that PRP contains high concentrations of growth factors (GFs) and proteins which contribute to the regenerative process. PRP based therapies are cost effective and also benefit from the accessibility and safety of using the patient's own GFs. In the last years, a great development has been witnessed on PRP based biomaterials, with both structural and functional purposes. In this study we overview the most relevant PRP applications encompassing PRP based materials for tissue engineering and regenerative medicine. This review also summarizes the challenges in the fields of tissue engineering and regenerative medicine and provides a perspective on future directions

Combination of hyaluronic acid and PLGA particles as hybrid systems for viscosupplementation in osteoarthritis

Hyaluronic acid (HA) is commonly used through intra-articular administration for viscosupplementation in osteoarthritis and other disorders. HA is generally supplied as an injection commonly reported as painful, with strong limitations after treatment. In this study, an alternative delivery system was constructed based on HA hydrogel and poly(lactic-co-glycolic acid) (PLGA) particles with oleic acid. Development studies included the determination of particle toxicity, hemolytic activity, in vitro and in vivo anti-inflammatory activity using macrophages and a murine model, respectively. This study showed that empty PLGA particles presented a mean size of 373 nm, while particles containing HA and oleic acid showed a marked particle size increase. The HA association efficiency was of 73.6% and 86.2% for PLGA particles without and with oleic acid, respectively. The in vitro HA release from PLGA particles revealed a sustained profile. Particles showed a good in vitro cell compatibility and the risk of hemolysis was less < 1%, ensuring their safety. The in vivo anti-inflammatory study showed a higher inhibition for HA-loaded PLGA particles when compared to HA solution (78% versus 60%) and they were not different from the positive control, clearly suggesting that this formulation may be a promising alternative to the current HA commercial dosage form.iMed.ULisboa [UID/DTP/04138/2013]CESAM [UID/AMB/50017/2019]FCT/MEC through Portuguese fundsFEDER, within the PT2020 Partnership AgreementCompete 202

Synchronous insight of in vitro and in vivo biological activities of Sambucus nigra L. extracts for industrial uses

There is a re-emerging interest in natural products as reputable sources of new active pharmaceutical ingredients. This study synchronously reports in vitro, with more than one cell line, and in vivo biological activities of extracts obtained from Sambucus nigra. Using several solvents and techniques, eighteen extracts were obtained from fresh and dried berries, and fresh flowers. The flavonoid content and identification were determined using HPLC-MS/MS. The extracts were then screened for antioxidant activity, total polyphenol content, collagenase, elastase, tyrosinase and acetylcholinesterase inhibition as well as photoprotection. In vitro and in vivo (murine model) anti-inflammatory activity and cytotoxicity (skin and monocytic cells) were also studied. The most promising extracts were those obtained from fresh flowers using either ultrasounds or methanol. These extracts showed similar results to positive controls, particularly the antioxidant activity (74.5 +/- 1.6 %), collagenase inhibition (93.6 +/- 0.6 %), photoprotection (Sun Protection Factor > 50), in vitro anti-inflammatory activity (96.9 +/- 2.9 %), as well as oral/topical anti-inflammatory activity. The ultrasounds/ethanol extract of fresh flowers presented higher collagenase inhibition (88.3 +/- 2.8 %) and in vitro anti-inflammatory activity (101.8 +/- 1.5 %). Cytotoxicity testing confirmed the safety. Chemical characterization allowed the deduction of a correlation between extract composition and biological activities, suggesting a straightforward application in the development of novel products subject to further investigation.Fundacao para a Ciencia e a TecnologiaPortuguese Foundation for Science and TechnologyEuropean Commission [UID/DTP/04138/2019]Portugal 2020 [LISBOA-01-0145-FEDER-402-022125]Portuguese National and Regional Budget [CCMAR/Multi/04326/2019]FCTPortuguese Foundation for Science and TechnologyEuropean Commission [SFRH/BD/116604/2016]FCT Scientific Employment Stimulus [CEECIND/00425/2017

Ciência, Crise e Mudança. 3.º Encontro Nacional de História das Ciências e da Tecnologia. ENHCT2012

III Encontro Nacional de História das Ciências e da Tecnologia. O Centro de Estudos de História e Filosofia da Ciência, organiza o 3.º Encontro Nacional de História da Ciência e da Técnica, sob o tema «Ciência, Crise e Mudança» que tem lugar na Universidade de Évora, nos dias 26, 27 e 28 de Setembro de 2012. O Primeiro Encontro Nacional de História da Ciência teve lugar em 21 e 22 Julho de 2009, no seguimento do programa de estímulo ao de¬senvolvimento da História da Ciência em Portugal e de valorização do património cultural e científico do País, lançado pelo Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) em 31 de Janeiro desse ano. A sua organização coube a investigadores do Instituto de História Contemporânea (IHC), da FCSH da UNL, e do Centro Científico e Cultural de Macau (CCCM), em cujas instalações se realizou. De en¬tre as conclusões do Encontro, destacou-se a de realizar periodicamen¬te novos Encontros Nacionais, a serem organizados de forma rotativa por diferentes centros e núcleos de investigadores. Na sequência deste Primeiro Encontro, o Centro Interuniversitário de História das Ciências e da Tecnologia (CIUHCT) organizou, entre 26 e 28 de Julho de 2010, o II Encontro, dedicado ao tema “Comunicação das Ciências e da Tecnologia em Portugal: Agentes, Meios e Audiências”. Cabe agora ao CEHFCi cumprir o que foi decidido no final deste Encontro. Na situação económica e política que hoje vivemos torna-se particularmente urgente aprofundar o estudo e o debate sobre a interação entre a Sociedade, a Ciência e a sua História. Coordenação Científica e Executiva do encontro estiveram a cargo de dois investigadores CEHFCi: Maria de Fátima Nunes, José Pedro Sousa Dia