Self-assembled hyaluronic acid nanoparticles: effect of molecular weight and two different chemical approaches

INTRODUCTION: Natural polyssacharides, such as hyaluronic acid (HyA) have been widely used for biomedical and pharmaceutical applications. Hya has multiple functional groups available for chemical conjugation that can convert HyA into nano-sized carriers. We prepared self-assembled HyA nanoparticles by two different chemical derivatization techniques and used two different molecular weights HyA. Our aim was to compare these two techniques and evaluate the influence of molecular weight in the properties of HyA nanoparticles. (...)(undefined

Scaffolds for Peripheral Nerve Regeneration, the Importance of In Vitro and In Vivo Studies for the Development of Cell-Based Therapies and Biomaterials: State of the Art

Human adult peripheral nerve injuries are a high incidence clinical problem that greatly affects patients’ quality of life. Although peripheral nervous system has intrinsic regenerative capacity, this occurs in an incomplete or poorly functional manner. When a nerve fiber loses its continuity with consequent damage of the basal lamina tubes, axon spontaneous regeneration is disorganized and mismatched. These phenomena translate in an inadequate nerve functional recovery and consequent musculoskeletal incapacity. Nerve grafts still remain the gold standard in peripheral injuries treatment. However, this approach contains its disadvantages such as the necessity of primary surgery to harvest the autografts, loss of a functional nerve, donor site morbidity and longer surgery procedures. Therefore, biomaterials and tissue engineering can provide efficient resources and alternatives to nerve injury repair not only by the development of biocompatible structures but also, introducing neurotrophic factors and cellular systems to stimulate optimum clinical outcome. In this chapter, a comprehensive state-of-the art picture of tissue-engineered nerve grafts scaffolds, their application in nerve regeneration along with latest advances in peripheral nerve repair and future perspectives will be discussed, including our own large experience in this field of knowledge

Optimization of hemicellulose extraction from sugarcane straw by autohydrolysis

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Biocompatibility of a self-assembled crosslinkable hyaluronic acid nanogel

Hyaluronic acid nanogel (HyA-AT) is a redox sensitive crosslinkable nanogel, obtained through the conjugation of a thiolated hydrophobic molecule to the hyaluronic acid chain. Engineered nanogel was studied for its biocompatibility, including immunocompatibility and hemocompatability. The nanogel did not compromise the metabolic activity or cellular membrane integrity of 3T3, microvascular endothelial cells, and RAW 264.7 cell lines, as determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide and lactate dehydrogenase release assays. Also, we didn't observe any apoptotic effect on these cell lines through the Annexin V-FITC test. Furthermore, the nanogel cell internalization was analyzed using murine bone marrow derived macrophages, and the in vivo and ex vivo biodistribution of the Cy5.5 labeled nanogel was monitored using a non-invasive near-infrared fluorescence imaging system. The HyA-AT nanogel exhibits fairly a long half-live in the blood stream, thus showing potential for drug delivery applications.The authors thank the FCT Strategic Project of UID/BIO/04469/2013 unit, the project RECI/ BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the Project “BioHealth – Biotechnology and Bioengineering approaches to improve health quality”, Ref. NORTE-07-0124- FEDER-000027, co-funded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER. The authors would like to acknowledge also the support of FCT for the PhD grant reference SFRH/BD/61516/2009. They would also like to thank Bioimaging department on Molecular Medicine Institute (IMM) in Lisbon, namely Dr José Rino and Dr António Temudo. Also thank the animal facilities in IMM (Lisbon), specially Dr. Dolores Bonaparte and Dr. Joana Marques. Finally, the authors thank Dr Africa Gonzalez and Mercedes Pelletero the performance of the studies on the activation of complement

Synovia-Derived Mesenchymal Stem Cell Application in Musculoskeletal Injuries: A Review

Musculoskeletal injuries impact millions of people globally and affect their health and well-being as well as of their companion and athletic animals. Soft-tissue injuries represent almost half of these and are associated with unorganized scar tissue formation and long time-depending healing processes. Cell-based therapeutic strategies have been developed in the past decades aiming at the treatment and reversion of such disorders. Stem cells are fairly appealing in the field, being a responsive undifferentiated population, with ability to self-renew and differentiate into different lineages. Mesenchymal stem cells (MSCs) can be obtained from several adult tissues, including the synovial membrane. Synovia-derived MSCs can be found in individuals of any age and are associated to intrinsic regenerative processes, through both paracrine and cell-to-cell interactions, thus, contributing to hosts’ healing capacity. Studies have demonstrated the potential benefit of synovia-derived MSCs in these regenerative processes in both human and veterinary medicine. The purpose of this chapter is to review the literature regarding SM-MSC therapies applied to musculoskeletal disorders, in both human and veterinary medicine

Self assembling nanogels

Este resumo faz parte de: Book of abstracts of the Meeting of the Institute for Biotechnology and Bioengineering, 2, Braga, Portugal, 2010. A versão completa do livro de atas está disponível em: http://hdl.handle.net/1822/1096

Elderberry Stalks as a Source of High-Value Phytochemical: Essential Minerals and Lipophilic Compounds

Elderberry (Sambucus nigra L.) consumption has been growing in the last years, generating a large number of stalks (~10% of the berries bunch) that are still under-valorized. This study focused on the evaluation of elderberry stalks as a source of high-value phytochemicals. In this vein, the essential mineral content and lipophilic composition were analyzed for the first time. In addition, the polar fraction was evaluated regarding its total phenolic content (TPC) and antioxidant activity by both 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2-diphenyl-1-picrylhydrazyl hydrate (DPPH) assays. The lipophilic fraction was mainly composed of triterpenic acids (2902.20 mg kg−1 of dry weight (dw)), fatty acids (711.73 mg kg−1 dw) and sterols (288.56 mg kg−1 dw). Minor amounts of long-chain aliphatic alcohols and other components were also detected. Ursolic acid (2265.83 mg kg−1 dw), hexadecanoic acid (219.85 mg kg−1 dw) and β-sitosterol (202.74 mg kg−1 dw) were the major lipophilic components verified. The results of this study also indicated that elderberry stalks might be used as a natural source of essential minerals, particularly calcium, iron and potassium, which are known to play important roles in various body functions. The analysis of the polar fraction also showed that elderberry stalks present TPC as high as elderberry themselves as well as considerable antioxidant activity (1.04 and 0.37 mmol TE g−1 of extract, against respectively ABTS and DPPH radicals). These results highlight the potential of elderberry stalks as a natural source of high-value phytochemicals that may be explored in several fieldspublishe

siRNA inhibition of endocytic pathways to characterize the cellular uptake mechanisms of folate-functionalized glycol chitosan nanogels

Glycol chitosan nanogels have been widely used in gene, drug, and contrast agent delivery in an effort to improve disease diagnosis and treatment. Herein, we evaluate the internalization mechanisms and intracellular fate of previously described glycol chitosan nanogels decorated with folate to target the folate receptor. Uptake of the folate-decorated nanogel was impaired by free folate, suggesting competitive inhibition and shared internalization mechanisms via the folate receptor. Nanogel uptake was shown to occur mainly through flotillin-1 and Cdc42-dependent endocytosis. This was determined by inhibition of uptake reduction observed upon siRNA depletion of these two proteins and the pathways that they regulate. The data also suggest the involvement of the actin cytoskeleton in nanogel uptake via macropinocytosis. After 7 h of incubation with HeLa cells, approximately half of the nanogel population was localized in endolysosomal compartments, whereas the remaining 50% of the material was in undefined regions of the cytoplasm. Glycol chitosan nanogels may thus have potential as drug delivery vectors for targeting different intracellular compartments.BioHealth - Biotechnology and Bioengineering approaches to improve health quality, Ref. NORTE-07-0124-FEDER-000027, cofunded by the Programa Operacional Regional do Norte (ON.2 − O Novo Norte), QREN, FEDER. P.P. was funded through an FCT Ph.D. grant (SFRH/BD/64977/2009). Funding is also acknowledged from a Cancer Research UK studentship (C36040/A11652), EPSRC Grant (EP/J021334/1 to A.T.J. and E.S.

Self-assembled nanoparticles made of fucan

Amphiphilic polymers can self-assemble in water due to hydrophilic and hydrophobic interactions, forming nanoparticles (NPs) with unique physicochemical characteristics and thermodynamic stability. A non toxic sulfated Fucan, extracted from Spatoglossum schroederi was chemically modified by the grafting of Hexadecylamine (C16) to the polymer hydrophilic backbone. The resulting modified material (Fucan-C16) formed nanosized particles which were characterized by 1H NMR to assess the substitution degree of the hydrophobic chains, fluorescence spectroscopy to determine the critical aggregation concentration (cac), cryo-field emission scanning electron microscopy (Cryo- FESEM) to evaluate the shape and size of the NPs, and dynamic light scattering (DLS) to verify the size distribution. The (cac) of Fucan-C16 NPs ranged between 0.05 and 0.03mg/mL. Cryo-FESEM revealed that Fucan-C16 formed spherical macromolecular particles with diameters between 120 and 180 nm, which were confirmed by DLS. In addition, the size of the NPs were not affected by the concentration of the polymer or by the variation of the pH.The size of nanoparticles increases with increasing its concentration in solution.CAPES, FCT and CNP