0000000000021513
AUTHOR
V. Brucato
Potential roles of extracellular vesicles in brain cell-to-cell communication
Potential roles of extracellular vesicles in brain cell-to-cell communication Extracellular vesicles (EVs) are released into thè extracellular space from both cancer and normal brain cells, and are probably able to modify thè phenotypic properties of receiving cells1. EVs released from astrocytes and neurons contain FGF2 and VEGF2'3 and induce a 'blood-brain barrier' (BBB) phenotype in cultured brain capillary endothelial cells (BCECs, unpublished results), On thè other hand, EVs from G26/24 oligodendroglioma induce apoptosis in neurons and astrocytes4-5. These effects are probably due to Fas Ligand and TRAIL, present in G26/24 vesicles4-5. Moreover, G26/24 EVs contain extracellular matrix …
PLLA Scaffold via TIPS for Bone Tissue Engineering
Tissue engineering offers a promising new approach to repair bone fractures, fractures that do not heal, and fractures due to bone tumors. In this work, two different approaches were tested in order to obtain Poly-L- Lactic Acid (PLLA) porous scaffolds via Thermally Induced Phase Separation (TIPS) for bone tissue engineering application. First, the possibility to produce a composite material, by incorporating Hydroxyapatite (HA) particles in a Poly-L-lactic acid (PLLA) matrix was investigated. Two PLLA/HA weight ratios (70/30 and 50/50) were tested. The results showed that the presence of HA does not influence the phase separation process, i.e. the composite scaffolds microstructure is simi…
In vitro bioactivity study of composite scaffold prepared via thermally induced phase separation
Among porous materials suitable for Bone Tissue Engineering (BTE) scaffolds, bioactive ceramics (hydroxyapatite, HA) and bioactive glasses (BG) have been used for their excellent biocompatibility, bioactivity and efficient osteointegration (1). However, their major limitations are brittleness, low mechanical stability and low dissolution rate (2). Recent evidences suggest that composite scaffold based on biodegradable polymers (e.g. Poly-lacticacid (PLLA)) simultaneously loaded with HA and BG hold promising potential as efficient osteoconductive implants (3, 4). In this work we investigated the possibility to produce composite PLLA-HA-BG scaffolds via Thermally Induced Phase Separation (TIP…
Optimization of environmental conditions for kefiran production by kefir grain as scaffold for tissue engineering
The aim of this work was to investigate the fermentation medium and environmental requirements for the production of exopolysaccharide (EPS) Kefiran from natural culture (Kefir grains). We have found that the fermentation medium and temperature are critical for Kefiran production during the 24 h cultivation of kefir grains. The Kefiran obtained from fat cow milk was used to evaluate its potential application as scaffold for tissue engineering. Kefiran scaffold were obtained via solvent casting and direct quenching. Thermal and morphology features were evaluated by DSC and SEM, respectively.
Evaluation of hydroxyapatite distribution in a Poly-L-Lactic Acid (PLLA) scaffolds via Micro Computed Tomography (µCT)
Bone Tissue Engineering offers promising clinical alternative substitutes for bone defects, focusing on the use of polymer/ceramic composites. Hydroxyapatite (HA), a bioactive ceramic, has been implemented in bone substitution and regeneration due to its biocompatibility, osteoconductivity and close resemblance to the mineralized phase of human bone. Several techniques have been adopted to characterize composite scaffolds in terms of morphology, pore size and interconnection, filler content and distribution, but most of them are destructives. In this work, composite Poly-L-Lactic Acid (PLLA)-HA scaffolds (17.6 mm diameter and35.7 mm height) were prepared via Thermally Induced Phase Separati…
Water Fluxes in Polymeric Membranes for Desalination via Membrane Distillation
Membrane distillation is an emerging technique for seawater desalination. Hydrophobic polymeric membranes are used to separate the solute‐free water vapour from the hot solution. Vapour fluxes of commercial polymeric membranes were measured in various conditions, i.e. natural and forced convection and vacuum. Vapour fluxes were also predicted with models and compared with experimentals. Higher fluxes were recorded in vacuum conditions.
Influence of“controlled processing conditions” on the solidification of iPP, PET and PA6
In this work reliable experimental data for three semicrystalline polymers (iPP, PA6, PET) crystallised under pressure and high cooling rates are supplied. These results were achieved on the basis of a model experiment where drastic controlled solidification conditions are applied. The final objective was to quantify the effect of two typical operating conditions (pressure and cooling rate) on the final properties and morphology of the obtained product. The influence of processing conditions on some macroscopically relevant properties, such as density and micro hardness is stressed, together with the influence of processing conditions on the product morphology, investigated by means of Wide…
A Biodegradable, Bio-Based Polymer for the Production of Tools for Aquaculture: Processing, Properties and Biodegradation in Sea Water
Bio-based, biodegradable polymers can dramatically reduce the carbon dioxide released into the environment by substituting fossil-derived polymers in some applications. In this work, prototypes of trays for aquaculture applications were produced via injection molding by using a biodegradable polymer, Mater-Bi®. A characterization carried out via calorimetric, rheological and mechanical tests revealed that the polymer employed shows properties suitable for the production of tools to be used in aquaculture applications. Moreover, the samples were subjected to a biodegradation test in conditions that simulate the marine environment. The as-treated samples were characterized from gravimetrical,…
Tubular composite scaffolds produced via Diffusion Induced Phase Separation (DIPS) as a shaping strategy for anterior cruciate ligaments reconstruction
Injuries of tendons and ligaments are common, especially among the young population. Anterior cruciate ligament (ACL) injuries do not heal due to its limited vascularization and hence, surgical intervention is usually required. The ideal scaffold for ligament tissue engineering (TE) should be biocompatible and possess mechanical and functional characteristics comparable to the native ACL. The Diffusion Induced Phase Separation (DIPS) technique allows the preparation of homogenous porous tubular scaffold with micro-pores using a rather simple procedure. Composites based on biodegradable polymers and bioglass have attracted much attention in tissue reconstruction and repair because of their b…
Hydroxyapatite/Chitosan/Collagen coatings through galvanic coupling
In this work, the attention was focused on Hydroxyapatite/ Chitosan/Collagen composite as biocoatings for application in orthopaedic devices. Hydroxyapatite was selected for its osteoconductivity due to its chemical structure similar to bones. Collagen has the same function since 90-95% of bone matrix is constituted of collagen fibers. Furthermore, chitosan are largely used yet in medical field (e.g. antibacterial agent or drug deliver) and in this work were used to create a synergic interaction with hydroxyapatite and collagen to increase the strength and bioactivity of coating. Coatings were fabricated by galvanic deposition process that has different advantages an it does not require ext…
BIOGLASS® integration in Poly-L-Lactic-Acid scaffolds produced via Thermally Induced Phase Separation (TIPS).
In this work, a method of integration of BG particles in polymeric scaffold was developed with a trial and error procedure. The main purpose was to obtain highly porous and mechanically stable bioactive devices.
Fabrication of Chitosan-Silver Nanoparticles composite coatings by galvanic deposition for orthopaedic implants
Poly lactic acid based scaffolds for vascular tissue engineering
A critical obstacle encountered by tissue engineering is the inability to maintain large masses of living cells upon transfer from the in vitro culture conditions to host in vivo. Capillaries, and the vascular system, are required to supply essential nutrients, including oxygen, remove waste products and provide a biochemical communication "highway". The successful use of tissue-engineered constructs is currently limited to thin or avascular tissues, such as skin or cartilage, for which post-implantation neovascularisation from the host is sufficient to meet the demand for oxygen and nutrients. To succeed in the application of tissue engineering for bigger tissues, such as bone or muscle, t…
BIOGLASS® pre-treatment improves its integration in polymeric scaffolds
Composite Coatings of Chitosan and Silver Nanoparticles Obtained by Galvanic Deposition for Orthopedic Implants
In this work, composite coatings of chitosan and silver nanoparticles were presented as an antibacterial coating for orthopedic implants. Coatings were deposited on AISI 304L using the galvanic deposition method. In galvanic deposition, the difference of the electrochemical redox potential between two metals (the substrate and a sacrificial anode) has the pivotal role in the process. In the coupling of these two metals a spontaneous redox reaction occurs and thus no external power supply is necessary. Using this process, a uniform deposition on the exposed area and a good adherence of the composite coating on the metallic substrate were achieved. Physical-chemical characterizations were car…