Studies in health technology and informatics, 2004
In this paper several issues concerning the development of fibers endowed with electronic functio... more In this paper several issues concerning the development of fibers endowed with electronic functions will be presented and discussed. In particular, issues concerning materials, structures, electronic models and the mechanical constraints due to textile technologies will be detailed. All these aspects have been studied in the framework of the project ARIANNE, funded by the European Community during the V Frame Programme.
Journal of Materials Science: Materials in Medicine, 2000
Awide range of rapid prototyping (RP) techniques for the construction of three-dimensional (3-D) ... more Awide range of rapid prototyping (RP) techniques for the construction of three-dimensional (3-D) scaffolds for tissue engineering has been recently developed. In this study, we report and compare two methods for the fabrication of poly-(epsilon-caprolactone) and poly-(epsilon-caprolactone)-poly-(oxyethylene)-poly-(epsilon-caprolactone) copolymer scaffolds. The first technique is based on the use of a microsyringe and a computer-controlled three-axis micropositioner, which regulates motor speed and position. Polymer solutions are extruded through the needle of the microsyringe by the application of a constant pressure of 10-300 mm Hg, resulting in controlled polymer deposition of 5-600 microm lateral dimensions. The second method utilises the heating energy of a laser beam to sinter polymer microparticles according to computer-guided geometries. Materials may be fed either as dry powder or slurry of microparticles. Both powder granulometry and laser working parameters influence resolution (generally 300 microm x 700 microm), accuracy of sintering and surface and bulk properties of the final structures. The two RP methods allow the fabrication of 3-D scaffolds with a controlled architecture, providing a powerful means to study cell response to an environment similar to that found
In this work, bioartificial binary blends between poly(ε-caprolactone) (PCL) and a polysaccharide... more In this work, bioartificial binary blends between poly(ε-caprolactone) (PCL) and a polysaccharide (chitosan (CS) or starch (S)) with different contents of the natural polymer (5–30 wt.%) were produced. Melt-mixing and double-precipitation were the methods used for the obtainment of PCL/S and PCL/CS blends, respectively. Tubular scaffolds were produced from bioartificial blends by melt-extrusion. Physico-chemical characterisation was performed by differential scanning calorimetry
Journal of Biomedical Materials Research Part A, 2010
Three-dimensional porous hydroxyapatite/collagen (HA/Coll) composites with a random pore structur... more Three-dimensional porous hydroxyapatite/collagen (HA/Coll) composites with a random pore structure were obtained by freeze-drying and crosslinked by an enzymatic treatment using microbial transglutaminase (mTGase). The procedure resulted in improved mechanical strength and thermal stability of the scaffolds. The scaffolds were characterized in terms of their stability (Coll release, swelling, collagenase-mediated degradation), thermal properties (thermogravimetric analysis, differential scanning calorimetry), mechanical behavior under compression and cell compatibility. Enzymatic treatment stabilized the sponges to water vapors, with measurable swelling ratio between 100% for HA/Coll/mTGase 0/100 to 5% for HA/Coll/mTGase 80/20. Weight loss in water due to Coll release was between 2 and 10% in mTGase-crosslinked samples and decreased with increasing HA content. Cultures of MG63 osteoblast-like cells and human umbilical vein endothelial cells (HUVEC) showed good adhesion and proliferation on the scaffolds, good viability (through MTT test, 100-150% of control), and good differentiation (alkaline phosphatase, up to 40 UI/L with respect to 35 UI/L for control).
Bioartificial blends of poly-(epsilon-caprolactone) (PCL) with a polysaccharide (starch, S; dextr... more Bioartificial blends of poly-(epsilon-caprolactone) (PCL) with a polysaccharide (starch, S; dextran, D; or gellan, G) (PCL/S, PCL/D, PCL/G 90.9/9.1 wt ratio) were prepared by a solution-precipitation technique and widely characterized by differential scanning calorimetry analysis (DSC), Fourier transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR), optical microscopy (OM), wide-angle X-ray diffraction analysis (WAXD), and thermogravimetry (TGA). DSC showed that the polysaccharide reduced the crystallinity of PCL and had a nucleation effect, which was also confirmed by OM analysis. Hoffman-Weeks analysis was performed on PCL and blend samples allowing calculation of their equilibrium melting temperatures (). WAXD showed that the crystalline unit cell type was the same for PCL and blends. FTIR-ATR did not evidence interactions between blend components. Thermal stability was affected by the type of polysaccharide. Microparticles (<125 microm) were produced from blends by cryogenical milling and characterized by scanning electron microscopy analysis (SEM). Selective laser sintering (SLS), a new rapid prototyping technology for scaffold fabrication, was applied to sinter blend microparticles according to a PC-designed two-dimensional geometry (strips and 2 x 2 mm(2) square-meshed grids). The optimal experimental conditions for sintering were established and laser beam parameters (beam speed, BS, and power, P) were found for each blend composition. Morphology of sintered objects was analyzed by SEM and found to be dependent on the morphology of the sintered powders. Sintered samples were analyzed by chemical imaging (CI), FTIR-ATR, DSC, and contact angle analysis. No evidence of the occurrence of degradation phenomena was found by FTIR-ATR for sintered samples, whereas DSC parameters of PCL and blends showed changes which could be attributed to some molecular weight decrease of PCL during sintering. CI of sintered samples showed that the polysaccharide phase was homogeneously dispersed within the PCL matrix, with the only exception being the PCL/D blend. The contact angle analysis showed that all samples were hydrophilic. Fibroblasts were then seeded on scaffolds to evaluate the rate and the extent of cell adhesion and the effect of the polysaccharides (S, D, G) on the bioactivity of the PCL-based blends.
In this study, we report a method for the fabrication of poly-(ε-caprolactone) (PCL) scaffolds, w... more In this study, we report a method for the fabrication of poly-(ε-caprolactone) (PCL) scaffolds, which utilizes the heating energy of a laser beam to sinter polymer microparticles according to computer-guided geometries, thus providing a powerful means to study cell response to an environment similar to that found in vivo.
Abstract Endothelial cells have central role in controlling blood vessels homeostasis, secreting ... more Abstract Endothelial cells have central role in controlling blood vessels homeostasis, secreting vasodilator (Nitric Oxide, NO) and vasoconstrictor (Endothelin-1, ET-1) molecules, in response to various shear-stress levels due to blood flow. ENMET (Endothelial cell ...
Adult muscle stem cells, or satellite cells have essential roles in homeostasis and regeneration ... more Adult muscle stem cells, or satellite cells have essential roles in homeostasis and regeneration of skeletal muscles. Satellite cells are located within a niche that includes myofibers and extracellular matrix. The function of specific extracellular matrix molecules in regulating SCs is poorly understood. Here, we show that the extracellular matrix protein collagen VI is a key component of the satellite cell niche. Lack of collagen VI in Col6a1(-/-) mice causes impaired muscle regeneration and reduced satellite cell self-renewal capability after injury. Collagen VI null muscles display significant decrease of stiffness, which is able to compromise the in vitro and in vivo activity of wild-type satellite cells. When collagen VI is reinstated in vivo by grafting wild-type fibroblasts, the biomechanical properties of Col6a1(-/-) muscles are ameliorated and satellite cell defects rescued. Our findings establish a critical role for an extracellular matrix molecule in satellite cell self-renewal and open new venues for therapies of collagen VI-related muscle diseases.
c o m p u t e r m e t h o d s a n d p r o g r a m s i n b i o m e d i c i n e 9 4 (2 0 0 9) 181–1... more c o m p u t e r m e t h o d s a n d p r o g r a m s i n b i o m e d i c i n e 9 4 (2 0 0 9) 181–189 a b s t r a c t Prediction and simulation of cell culture behaviour, under different chemical and physical stimuli by a mathematical model, represent an innovative way to create a virtual cell laboratory , where it is possible to perform and optimize experimental protocol, saving time and money. In silico experiments permit to reproduce pathological and physiological situations and make toxicological tests. In this paper we introduce a new library of HEMET (HEpatocyte METabolism) software that allows the insulin effects on hepatic metabolism to be simulated. This new set of nonlinear differential equations, derived from biochemical reactions which involve this pancreatic hormone, allows the catabolites concentration in hepatic cell culture after insulin infusion to be predicted. The validation procedures were carried out using data obtained from specifically designed cell experiments and from literature. A user friendly interface allows to easily change model parameters, rate constants and inputs simulating a wide range of physiological and pathological scenarios.
In this study, we report a method for the fabrication of poly-(ε-caprolactone) (PCL) scaffolds, w... more In this study, we report a method for the fabrication of poly-(ε-caprolactone) (PCL) scaffolds, which utilizes the heating energy of a laser beam to sinter polymer microparticles according to computer-guided geometries, thus providing a powerful means to study cell response to an environment similar to that found in vivo.
The International journal of artificial organs, 2010
In recent years, research in the field of myocardial tissue engineering has advanced thanks to th... more In recent years, research in the field of myocardial tissue engineering has advanced thanks to the development of new biomaterials and a more clear understanding of processes that are at the basis of cardiac tissue growth. However, classical porous scaffolds developed during these years to try to reconstruct and mimic heart function have proven to be inadequate because they are not able to reproduce the typical myocardial environment. One approach to increase functionality of tissue-engineered constructs relies on attempts to mimic the microarchitecture of natural tissues, since it is well known that topology is one of the principal stimuli that cells need to activate their functions. The aim of this work was the realization of three-dimensional microfabricated scaffolds, with cardiac extracellular matrix (ECM)-like architecture. For this purpose, samples of pig myocardium were decellularized, embedded in paraffin wax and analyzed under an optical microscope, in order to evaluate th...
Studies in health technology and informatics, 2004
In this paper several issues concerning the development of fibers endowed with electronic functio... more In this paper several issues concerning the development of fibers endowed with electronic functions will be presented and discussed. In particular, issues concerning materials, structures, electronic models and the mechanical constraints due to textile technologies will be detailed. All these aspects have been studied in the framework of the project ARIANNE, funded by the European Community during the V Frame Programme.
Journal of Materials Science: Materials in Medicine, 2000
Awide range of rapid prototyping (RP) techniques for the construction of three-dimensional (3-D) ... more Awide range of rapid prototyping (RP) techniques for the construction of three-dimensional (3-D) scaffolds for tissue engineering has been recently developed. In this study, we report and compare two methods for the fabrication of poly-(epsilon-caprolactone) and poly-(epsilon-caprolactone)-poly-(oxyethylene)-poly-(epsilon-caprolactone) copolymer scaffolds. The first technique is based on the use of a microsyringe and a computer-controlled three-axis micropositioner, which regulates motor speed and position. Polymer solutions are extruded through the needle of the microsyringe by the application of a constant pressure of 10-300 mm Hg, resulting in controlled polymer deposition of 5-600 microm lateral dimensions. The second method utilises the heating energy of a laser beam to sinter polymer microparticles according to computer-guided geometries. Materials may be fed either as dry powder or slurry of microparticles. Both powder granulometry and laser working parameters influence resolution (generally 300 microm x 700 microm), accuracy of sintering and surface and bulk properties of the final structures. The two RP methods allow the fabrication of 3-D scaffolds with a controlled architecture, providing a powerful means to study cell response to an environment similar to that found
In this work, bioartificial binary blends between poly(ε-caprolactone) (PCL) and a polysaccharide... more In this work, bioartificial binary blends between poly(ε-caprolactone) (PCL) and a polysaccharide (chitosan (CS) or starch (S)) with different contents of the natural polymer (5–30 wt.%) were produced. Melt-mixing and double-precipitation were the methods used for the obtainment of PCL/S and PCL/CS blends, respectively. Tubular scaffolds were produced from bioartificial blends by melt-extrusion. Physico-chemical characterisation was performed by differential scanning calorimetry
Journal of Biomedical Materials Research Part A, 2010
Three-dimensional porous hydroxyapatite/collagen (HA/Coll) composites with a random pore structur... more Three-dimensional porous hydroxyapatite/collagen (HA/Coll) composites with a random pore structure were obtained by freeze-drying and crosslinked by an enzymatic treatment using microbial transglutaminase (mTGase). The procedure resulted in improved mechanical strength and thermal stability of the scaffolds. The scaffolds were characterized in terms of their stability (Coll release, swelling, collagenase-mediated degradation), thermal properties (thermogravimetric analysis, differential scanning calorimetry), mechanical behavior under compression and cell compatibility. Enzymatic treatment stabilized the sponges to water vapors, with measurable swelling ratio between 100% for HA/Coll/mTGase 0/100 to 5% for HA/Coll/mTGase 80/20. Weight loss in water due to Coll release was between 2 and 10% in mTGase-crosslinked samples and decreased with increasing HA content. Cultures of MG63 osteoblast-like cells and human umbilical vein endothelial cells (HUVEC) showed good adhesion and proliferation on the scaffolds, good viability (through MTT test, 100-150% of control), and good differentiation (alkaline phosphatase, up to 40 UI/L with respect to 35 UI/L for control).
Bioartificial blends of poly-(epsilon-caprolactone) (PCL) with a polysaccharide (starch, S; dextr... more Bioartificial blends of poly-(epsilon-caprolactone) (PCL) with a polysaccharide (starch, S; dextran, D; or gellan, G) (PCL/S, PCL/D, PCL/G 90.9/9.1 wt ratio) were prepared by a solution-precipitation technique and widely characterized by differential scanning calorimetry analysis (DSC), Fourier transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR), optical microscopy (OM), wide-angle X-ray diffraction analysis (WAXD), and thermogravimetry (TGA). DSC showed that the polysaccharide reduced the crystallinity of PCL and had a nucleation effect, which was also confirmed by OM analysis. Hoffman-Weeks analysis was performed on PCL and blend samples allowing calculation of their equilibrium melting temperatures (). WAXD showed that the crystalline unit cell type was the same for PCL and blends. FTIR-ATR did not evidence interactions between blend components. Thermal stability was affected by the type of polysaccharide. Microparticles (<125 microm) were produced from blends by cryogenical milling and characterized by scanning electron microscopy analysis (SEM). Selective laser sintering (SLS), a new rapid prototyping technology for scaffold fabrication, was applied to sinter blend microparticles according to a PC-designed two-dimensional geometry (strips and 2 x 2 mm(2) square-meshed grids). The optimal experimental conditions for sintering were established and laser beam parameters (beam speed, BS, and power, P) were found for each blend composition. Morphology of sintered objects was analyzed by SEM and found to be dependent on the morphology of the sintered powders. Sintered samples were analyzed by chemical imaging (CI), FTIR-ATR, DSC, and contact angle analysis. No evidence of the occurrence of degradation phenomena was found by FTIR-ATR for sintered samples, whereas DSC parameters of PCL and blends showed changes which could be attributed to some molecular weight decrease of PCL during sintering. CI of sintered samples showed that the polysaccharide phase was homogeneously dispersed within the PCL matrix, with the only exception being the PCL/D blend. The contact angle analysis showed that all samples were hydrophilic. Fibroblasts were then seeded on scaffolds to evaluate the rate and the extent of cell adhesion and the effect of the polysaccharides (S, D, G) on the bioactivity of the PCL-based blends.
In this study, we report a method for the fabrication of poly-(ε-caprolactone) (PCL) scaffolds, w... more In this study, we report a method for the fabrication of poly-(ε-caprolactone) (PCL) scaffolds, which utilizes the heating energy of a laser beam to sinter polymer microparticles according to computer-guided geometries, thus providing a powerful means to study cell response to an environment similar to that found in vivo.
Abstract Endothelial cells have central role in controlling blood vessels homeostasis, secreting ... more Abstract Endothelial cells have central role in controlling blood vessels homeostasis, secreting vasodilator (Nitric Oxide, NO) and vasoconstrictor (Endothelin-1, ET-1) molecules, in response to various shear-stress levels due to blood flow. ENMET (Endothelial cell ...
Adult muscle stem cells, or satellite cells have essential roles in homeostasis and regeneration ... more Adult muscle stem cells, or satellite cells have essential roles in homeostasis and regeneration of skeletal muscles. Satellite cells are located within a niche that includes myofibers and extracellular matrix. The function of specific extracellular matrix molecules in regulating SCs is poorly understood. Here, we show that the extracellular matrix protein collagen VI is a key component of the satellite cell niche. Lack of collagen VI in Col6a1(-/-) mice causes impaired muscle regeneration and reduced satellite cell self-renewal capability after injury. Collagen VI null muscles display significant decrease of stiffness, which is able to compromise the in vitro and in vivo activity of wild-type satellite cells. When collagen VI is reinstated in vivo by grafting wild-type fibroblasts, the biomechanical properties of Col6a1(-/-) muscles are ameliorated and satellite cell defects rescued. Our findings establish a critical role for an extracellular matrix molecule in satellite cell self-renewal and open new venues for therapies of collagen VI-related muscle diseases.
c o m p u t e r m e t h o d s a n d p r o g r a m s i n b i o m e d i c i n e 9 4 (2 0 0 9) 181–1... more c o m p u t e r m e t h o d s a n d p r o g r a m s i n b i o m e d i c i n e 9 4 (2 0 0 9) 181–189 a b s t r a c t Prediction and simulation of cell culture behaviour, under different chemical and physical stimuli by a mathematical model, represent an innovative way to create a virtual cell laboratory , where it is possible to perform and optimize experimental protocol, saving time and money. In silico experiments permit to reproduce pathological and physiological situations and make toxicological tests. In this paper we introduce a new library of HEMET (HEpatocyte METabolism) software that allows the insulin effects on hepatic metabolism to be simulated. This new set of nonlinear differential equations, derived from biochemical reactions which involve this pancreatic hormone, allows the catabolites concentration in hepatic cell culture after insulin infusion to be predicted. The validation procedures were carried out using data obtained from specifically designed cell experiments and from literature. A user friendly interface allows to easily change model parameters, rate constants and inputs simulating a wide range of physiological and pathological scenarios.
In this study, we report a method for the fabrication of poly-(ε-caprolactone) (PCL) scaffolds, w... more In this study, we report a method for the fabrication of poly-(ε-caprolactone) (PCL) scaffolds, which utilizes the heating energy of a laser beam to sinter polymer microparticles according to computer-guided geometries, thus providing a powerful means to study cell response to an environment similar to that found in vivo.
The International journal of artificial organs, 2010
In recent years, research in the field of myocardial tissue engineering has advanced thanks to th... more In recent years, research in the field of myocardial tissue engineering has advanced thanks to the development of new biomaterials and a more clear understanding of processes that are at the basis of cardiac tissue growth. However, classical porous scaffolds developed during these years to try to reconstruct and mimic heart function have proven to be inadequate because they are not able to reproduce the typical myocardial environment. One approach to increase functionality of tissue-engineered constructs relies on attempts to mimic the microarchitecture of natural tissues, since it is well known that topology is one of the principal stimuli that cells need to activate their functions. The aim of this work was the realization of three-dimensional microfabricated scaffolds, with cardiac extracellular matrix (ECM)-like architecture. For this purpose, samples of pig myocardium were decellularized, embedded in paraffin wax and analyzed under an optical microscope, in order to evaluate th...
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