Natural fibres as reinforcement strategy on cork-polymer composites

Cork powder, the most important sub-product of cork processing, combined with thermoplastic matrixes like, high density polyethylene (HDPE), offer a new class of cork-polymer composite (CPC) materials with high added-value. Therefore, reinforcing strategies must be considered to increase the mechanical performance, especially when high content of cork powder is added to the formulation. Coconut fibres have several advantages, such as, low density, renewable source, low cost and biodegradability. The use of these fibres on the reinforcement of CPC materials will not only contribute to improve the mechanical performance but also for increasing the amount of natural component present on the final composition. The main goal of this work was to prepare HDPE/cork (50-50 wt.%) composites reinforced with discontinuous coconut fibres (5 and 10 wt.%) with and without the addition of coupling agent (2 wt.%) by extrusion. The developed reinforced cork based composites were characterized regarding its morphology and mechanical performance. Optical micrographs have shown a homogeneous distribution of the fibres. The coupling agent effect on CPC performance was also investigated. The tensile strength and tensile modulus of the reinforced composites were significantly improved with the addition of coupling agent. The use of 10 wt.% of coconut fibres in the presence of coupling agent promote an increase on maximum tensile strength of around 41 % comparing with the HDPE/cork (50-50 wt.%) composites. Scanning electron microscopy (SEM) micrographs of the tensile fractured specimens confirmed that the use of coupling agent promoted the interfacial adhesion between the fibres and the thermoplastic matrix. Since, like cork powder, coconut fibres have good thermal and acoustic properties, we consider that the novel reinforced CPC herein described have high potential to be used in building and construction systems and other structural 3D applications.Corticeira Amorim S.G.P.S. (Portugal)Fundação para a Ciência e a Tecnologia (FCT)Project ”NovelComp”QREN FCOMP-01-0202 FEDER-00310

Novel cork-polymer composites reinforced with short natural coconut fibres : effect of fibre loading and coupling agent addition

Composites from high density polyethylene filled with cork powder and coconut short fibres, in two different ratios, were prepared in a twin-screw extruder followed by compression moulding process. The main motivation of this work was to improve the mechanical performance without compromising the use of high weight percentage of natural component used in the preparation of cork-based composites. The morphology of the hybrid composites were more homogeneous in the presence of the coupling agent (CA) displaying enhanced fibre–matrix adhesion. Moreover, the use of CA based on maleic anhydride promotes a mechanical reinforcement effect on the tensile properties, including the elongation at break. The addition of coconut fibre resulted on an increase of 27% in elastic modulus and 47% in the tensile strength when compared with the unreinforced cork-based (50–50) wt.% composite. This work clearly shows that the addition of 10 wt.% of short-coconut fibres, randomly distributed, can be effectively used as reinforcing strategy of cork-based composite materials, preferably in the presence of 2 wt.% of CA.The work was performed within the project of Corticeira Amorim S.G.P.S. on the development of new products based in/with cork. We gratefully acknowledge to Amorim Revestimentos S.A. for the supply of cork and to Amorim Isolamentos S.A. for the coconut fibres and to Pallmann GmbH for the grinding polymer. E.M.F. and V.M.C. acknowledges to Portuguese Foundation for Science and Technology (FCT) grants (SFRH/BD/71561/2010) and (SFRH/BPD/64790/2009) respectively

Novel PHB/PCL scaffolds produced by melt base technologies

[Excerpt] On this work, the natural origin polymer Polyhydroxybutyrate (PHB) was melt blended with synthetic aliphatic polyester Polye-caprolactone (PCL). The ratio of PHB/PCL was varied from 25% to 75% by weight. These blends were further injection moulded and characterized. The thermal properties of the developed blends were accessed by differential scanning calorimetry DSC). The effect of the ratio PHB/PCL on the mechanical properties (tensile modulus and tensile strength) was determined by tensile tests. […]info:eu-repo/semantics/publishedVersio

Tumor - stroma interactions alter the sensitivity of drug in breast cancer

Flat cell cultures or xenografts are inadequate tools to unravel cancer complex biology. 3D in vitro tumor models garnered interest since they recapitulate better dynamic mechanisms of cancer, but a gold standardmodel that faithfullymimics solid cancer is not available yet. 3D breast cancermodel is fabricated using freeze-dried silk fibroin scaffolds. Breast cancer cell lines (MCF-7 and MDA-MB231) are seeded with normal mammary fibroblasts onto silk fibroin scaffold (1 and 2mm thick). Cells proliferation is monitored by means of Alamar blue assay. 3D breast cancer models morphology is observed by confocal microscopy. Gene expression modulation concerning extracellular matrix markers is evaluated. Further, 3D bioengineered breast cancer models are treated with doxorubicin. Silk fibroin scaffolds allow the proliferation of cancer cells and fibroblasts. Cells growth is enhanced when cancer cells and fibroblasts are seeded together. Histological staining shows 3D cell organization. MMP-1, MMP-2, MMP-3, Col-1, and Fibronectin expression is upregulated in co-culture. After doxorubicin treatment, stronger reduction in cell activity is observed in 2mm SF scaffold in comparison to 1mm. The 3D in vitro breast cancer model obtained can easily be scaled-up and translated to the preclinical testing of novel chemotherapeutics.This work was supported by EU-Horizon 2020 grant FoReCaST—Forefront Research in 3D Disease Cancer Modelsasin vitroScreening Technologies (H2020-WIDESPREAD-2014-668983). The authors also acknowledge the FRONTHERA project (Frontiers of technology for theranostics of cancer,metabolic and neurodegenerative diseases) (NORTE-01-0145-FEDER-0000232) and Fundação Ciência e tecnologia (FCT grantagreement: PTDC/BTM-ORG/28168/2017 to VB and SK)

Evaluating biomaterial-and microfluidic-based 3D tumor models

Cancer is a major cause of morbidity and mortality worldwide, with a disease burden estimated to increase in the coming decades. Disease heterogeneity and limited information on cancer biology and disease mechanisms are aspects that 2D cell cultures fail to address. We review the current "state-of-the-art" in 3D Tissue Engineering (TE) models developed for and used in cancer research. Scaffold-based TE models and microfluidics, are assessed for their potential to fill the gap between 2D models and clinical application. Recent advances in combining the principles of 3D TE models and microfluidics are discussed, with a special focus on biomaterials and the most promising chip-based 3D models.The authors would like to thank the European Union's Seventh Framework Program (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS, and QREN (ON.2 - NORTE-01-0124-FEDER-000016) co-financed by North Portugal Regional Operational Program (ON.2 - O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF) for providing financial support to this project. The FCT distinction attributed to J.M.O. under the Investigator FCT program (IF/00423/2012) Is also greatly acknowledged

Redox activity of melanin from the ink sac of Sepia officinalis by means of colorimetric oxidative assay

The redox properties of natural extract from cuttlefish ink sac (Sepia officinalis) and synthetic melanin used as a biomimetic in melanin structural investigation were determined by comparison of this phenol-based heterogeneous pigment with gallic acid used as a standard in Folinâ Ciocalteu colorimetric assay widely employed for characterisation of oxidative properties of biomaterials. Reactivity of sepia melanin reported here is much higher than previously indicated and this protocol should allow the redox characterisation of all melanins irrespective of their origin and composition.European Union’s Seventh Framework Programme (FP7/2007-2013) [grant agreement number REGPOT-CT2012-316331-POLARIS

Cork based composites using polyolefin’s as matrix : morphology and mechanical performance

The cork industry produces high amounts of cork powders resulting from the final stages of cork processing or resulting from existing cork products. Usually these powders are burned and served to boilers in industrial processes. The main goal of this work is to transform this cork sub-product into a highly value composite product. The real value is dependent on the mechanical performance of this product. Thus the mixture between cork and thermoplastics, particularly the improvement of interfacial bonding, is an important topic, which needs to be developed. The interfacial affinity can be greatly increased, applying superficial modification of one of the components, or by the use of coupling agents. In this work, a high amount of cork powder (50 wt.%) from different origins combined with different thermoplastic materials using melt based processes has been examined. Pultrusion was used to produce pellets and compression moulding to obtain boards to determine its properties. Coupling agents based on maleic anhydride (2 wt.%) improved the tensile strength successfully, while the cork powder has an a important role in the stiffness. The morphology of the surface fractures indicated a good dispersion of the cork and a good adhesion between both phases. Thermal properties of the composites disclosed a nucleating effect promoted by cork

In vitro cancer models: a closer look at limitations on translation

In vitro cancer models are envisioned as high-throughput screening platforms for potential new therapeutic discovery and/or validation. They also serve as tools to achieve personalized treatment strategies or real-time monitoring of disease propagation, providing effective treatments to patients. To battle the fatality of metastatic cancers, the development and commercialization of predictive and robust preclinical in vitro cancer models are of urgent need. In the past decades, the translation of cancer research from 2D to 3D platforms and the development of diverse in vitro cancer models have been well elaborated in an enormous number of reviews. However, the meagre clinical success rate of cancer therapeutics urges the critical introspection of currently available preclinical platforms, including patents, to hasten the development of precision medicine and commercialization of in vitro cancer models. Hence, the present article critically reflects the difficulty of translating cancer therapeutics from discovery to adoption and commercialization in the light of in vitro cancer models as predictive tools. The state of the art of in vitro cancer models is discussed first, followed by identifying the limitations of bench-to-bedside transition. This review tries to establish compatibility between the current findings and obstacles and indicates future directions to accelerate the market penetration, considering the niche market.This work is supported by FROnTHERA (NORTE-01-0145-FEDER-000023) and the European Union Framework Programme for Research and Innovation Horizon 2020 under grant agreement No. 668983 —FoReCaST. N. Antunes thanks the funds provided by FCT under the doctoral program in Tissue Engineering, Regenerative Medicine and Stem Cells (PD/BD/143050/2018). SCK also records the support of FCT through the BREAST-IT project (PTDC/BTM-ORG/28168/2017)

Properties of melt processed chitosan and aliphatic polyester blends

The activities (at pH 7 and 50°C) of purified EGV (Humicola insolens) and CenA (Cellulomonas fimi) were determined on cotton fabrics at high and low levels of mechanical agitation. Similar activity measurements were also made by using the core domains of these cellulases. Activity experiments suggested that the presence of cellulose binding domains (CBDs) is not essential for cellulase performance in the textile processes, where high levels of mechanical agitation are applied. The binding reversibilities of these cellulases and their cores were studied by dilution of the treatment liquor after equilibrium adsorption. EGV showed low percentage of adsorption under both levels of agitation. It was observed that the adsorption/desorption processes of cellulases are enhanced by higher mechanical agitation levels and that the binding of cellulase with CBD of family I (EGV) is more reversible than that of CBD of the cellulase of family II (CenA)

Properties of new cork–polymer composites : advantages and drawbacks as compared with commercially available fibreboard materials

The work creates a viable and profitable alternative to storage or burn of cork powder. ► Cork–polymer composite materials for building applications such as core in flooring. ► The cork composites show low water absorption and low thickness swelling variation. ► Cork improved the fire resistance of the thermoplastic composites. ► Composites with good acoustic behaviour as compare with the commercial fibre boards.Cork powder (50 wt.%) was mixed with polypropylene (PP) or polyethylene (PE) by pultrusion aiming to prepare cork-based composites. In a further step, samples were produced by compression moulding using the compounded composites. Bending strength, impact resistance, hardness, dimensional stability, thermal and acoustic properties of the developed cork-polymer composites (CPC) were determined and compared with commercially available products namely medium density fibreboard (MDF) and high density fibreboard (HDF). It was found that the CPC have good dimensional stability, lower water uptake, a better acoustic insulation performance and similar behaviour in terms of hardness and fire resistance when compared with both MDF and HDF. However, the mechanical strength is inferior comparing with both commercial materials based on fibres. It was also observed that addition of cork improved the flexural modulus, impact resistance and hardness on the developed CPC. Thus, the herein described CPC materials showed important characteristics to be considered as good candidates to be applied in the design of flooring and construction systems.Fundação para a Ciência e a Tecnologia (FCT)Corticeira Amorim S.G.P.S