Search results for "Biomaterial"
showing 10 items of 1350 documents
Molecular strategies to increase yeast iron accumulation and resistance.
2018
All eukaryotic organisms rely on iron as an essential micronutrient for life because it participates as a redox-active cofactor in multiple biological processes. However, excess iron can generate reactive oxygen species that damage cellular macromolecules. The low solubility of ferric iron at physiological conditions increases the prevalence of iron deficiency anemia. A common strategy to treat iron deficiency consists of dietary iron supplementation. The baker’s yeast Saccharomyces cerevisiae is used as a model eukaryotic organism, but also as a feed supplement. In response to iron deficiency, the yeast Aft1 transcription factor activates cellular iron acquisition. However, when constituti…
The development of a tissue-engineered tracheobronchial epithelial model using a bilayered collagen-hyaluronate scaffold
2016
Today, chronic respiratory disease is one of the leading causes of mortality globally. Epithelial dysfunction can play a central role in its pathophysiology. The development of physiologically-representative in vitro model systems using tissue-engineered constructs might improve our understanding of epithelial tissue and disease. This study sought to engineer a bilayered collagen-hyaluronate (CHyA-B) scaffold for the development of a physiologically-representative 3D in vitro tracheobronchial epithelial co-culture model. CHyA-B scaffolds were fabricated by integrating a thin film top-layer into a porous sub-layer with lyophilisation. The film layer firmly connected to the sub-layer with del…
3D printing of hybrid biomaterials for bone tissue engineering: Calcium-polyphosphate microparticles encapsulated by polycaprolactone.
2017
Abstract Here we describe the formulation of a morphogenetically active bio-ink consisting of amorphous microparticles (MP) prepared from Ca 2+ and the physiological inorganic polymer, polyphosphate (polyP). Those MP had been fortified by mixing with poly-e-caprolactone (PCL) to allow 3D-bioprinting. The resulting granular PCL/Ca-polyP-MP hybrid material, liquefied by short-time heating to 100 °C, was used for the 3D-printing of tissue-like scaffolds formed by strands with a thickness of 400 µm and a stacked architecture leaving ≈0.5 mm 2 -sized open holes enabling cell migration. The printed composite scaffold turned out to combine suitable biomechanical properties (Young’s modulus of 1.60…
Salmon fibrinogen and chitosan scaffold for tissue engineering: in vitro and in vivo evaluation
2018
3D fibrous scaffolds have received much recent attention in regenerative medicine. Use of fibrous scaffolds has shown promising results in tissue engineering and wound healing. Here we report the development and properties of a novel fibrous scaffold that is useful for promoting wound healing. A scaffold made of salmon fibrinogen and chitosan is produced by electrospinning, resulting in a biocompatible material mimicking the structure of the native extracellular matrix (ECM) with suitable biochemical and mechanical properties. The scaffold is produced without the need for enzymes, in particular thrombin, but is fully compatible with their addition if needed. Human dermal fibroblasts culture…
Large strain stimulation promotes extracellular matrix production and stiffness in an elastomeric scaffold model
2016
Mechanical conditioning of engineered tissue constructs is widely recognized as one of the most relevant methods to enhance tissue accretion and microstructure, leading to improved mechanical behaviors. The understanding of the underlying mechanisms remains rather limited, restricting the development of in silico models of these phenomena, and the translation of engineered tissues into clinical application. In the present study, we examined the role of large strip-biaxial strains (up to 50%) on ECM synthesis by vascular smooth muscle cells (VSMCs) micro-integrated into electrospun polyester urethane urea (PEUU) constructs over the course of 3 weeks. Experimental results indicated that VSMC …
Human platelet-rich plasma improves the nesting and differentiation of human chondrocytes cultured in stabilized porous chitosan scaffolds
2017
[EN] The clinical management of large-size cartilage lesions is difficult due to the limited regenerative ability of the cartilage. Different biomaterials have been used to develop tissue engineering substitutes for cartilage repair, including chitosan alone or in combination with growth factors to improve its chondrogenic properties. The main objective of this investigation was to evaluate the benefits of combining activated platelet-rich plasma with a stabilized porous chitosan scaffold for cartilage regeneration. To achieve this purpose, stabilized porous chitosan scaffolds were prepared using freeze gelation and combined with activated platelet-rich plasma. Human primary articular chond…
Polysaccharide-based silver nanoparticles synthesized by Klebsiella oxytoca DSM 29614 cause DNA fragmentation in E-coli cells
2016
Silver nanoparticles (AgNPs), embedded into a specific exopolysaccharide (EPS), were produced by Klebsiella oxytoca DSM 29614 by adding AgNO3 to the cultures during exponential growth phase. In particular, under aerobic or anaerobic conditions, two types of silver nanoparticles, named AgNPs-EPS(aer) and the AgNPs-EPS(anaer), were produced respectively. The effects on bacterial cells was demonstrated by using Escherichia coli K12 and Kocuria rhizophila ATCC 9341 (ex Micrococcus luteus) as Gram-negative and Gram-positive tester strains, respectively. The best antimicrobial activity was observed for AgNPs-EPS(aer), in terms of minimum inhibitory concentrations and minimum bactericidal concentr…
Fractional hereditariness of lipid membranes: Instabilities and linearized evolution
2016
In this work lipid ordering phase changes arising in planar membrane bilayers is investigated both accounting for elas- ticity alone and for effective viscoelastic response of such assemblies. The mechanical response of such membranes is studied by minimizing the Gibbs free energy which penalizes perturbations of the changes of areal stretch and their gradients only [1]. As material instabilities arise whenever areal stretches characterizing homogeneous configurations lie inside the spinoidal zone of the free energy density, bifurcations from such configurations are shown to occur as oscillatory perturbations of the in-plane displacement. Experimental observations [2] show a power-law in-pl…
Fabrication of a new physiological macroporous hybrid biomaterial/bioscaffold material based on polyphosphate and collagen by freeze-extraction
2020
We describe the fabrication of a new scaffold, an inorganic–organic hybrid biomaterial, consisting of the physiological polymers: the inorganic polymer polyphosphate (polyP), as well as the organic macromolecules collagen and chondroitin sulfate. The polyP polymer is composed of multiple phosphate orthophosphate units linked together by high-energy phosphoanhydride bonds. Chondroitin sulfate has been included due to its hydrogel-forming properties. In the presence of Ca2+ ions, the randomly coiled polyP reorganizes together with collagen and chondroitin sulfate to linear molecules which undergo hardening. This scaffold is deposited as amorphous Ca–polyP nanoparticles (size ≈20–40 nm large) …
Effect of substrate composition on the stability and microbial community of an anaerobic expanded granular sludge bed reactor treating printing solve…
2019
Abstract The performance and microbial community analysis of an expanded granular sludge bed reactor (EGSB) treating wastewater polluted with mixtures of ethanol and glycol ethers –such as 1-ethoxy-2-propanol (E2P) and 1-methoxy-2-propanol (M2P)– were evaluated. The results showed good EGSB performance during start-up (100% of ethanol) in terms of global removal efficiency (RE > 95%). When glycol ethers were added, an initial adaptation period was observed of ~20 days. While the RE of M2P became complete, the RE of E2P reached only 65%. The proportion of glycol ethers was gradually increased and at the end of this study only a binary mixture of E2P and M2P was fed. In the last stage, the gl…