While most of the studies on molecular machines have been performed in solution, interfacing thes... more While most of the studies on molecular machines have been performed in solution, interfacing these supramolecular systems with solid-state nanostructures and materials is very important in view of their utilization in sensing components working by chemical and photonic actuation. Host polymeric materials, and particularly polymer nanofibers, enable the manipulation of the functional molecules constituting molecular machines and provide a way to induce and control the supramolecular organization. Here, we present electrospun nanocomposites embedding a self-assembling rotaxane-type system that is responsive to both optical (UV-vis light) and chemical (acid/base) stimuli. The system includes a molecular axle comprised of a dibenzylammonium recognition site and two azobenzene end groups and a dibenzo[24]crown-8 molecular ring. The dethreading and rethreading of the molecular components in nanofibers induced by exposure to base and acid vapors, as well as the photoisomerization of the azobenzene end groups, occur in a similar manner to what observed in solution. Importantly, however, the nanoscale mechanical function following external chemical stimuli induces a measurable variation of the macroscopic mechanical properties of nanofibers aligned in arrays, whose Young's modulus is significantly enhanced upon dethreading of the axles from the rings. These composite nanosystems show therefore great potential for application in chemical sensors, photonic actuators, and environmentally responsive materials.
Journal of Tissue Engineering and Regenerative Medicine, 2012
In the last decade, the importance of topographic properties of extracellular environments has be... more In the last decade, the importance of topographic properties of extracellular environments has been shown to be essential to addressing cell response, especially when replacing damaged tissues with functional constructs obtained in vitro. In the current study, densely packed sub-micron poly (3-hydroxybutyrate) (PHB) fibres were electrospun with random and parallel orientations. PC12 pheochromocytoma cells that mimic central dopaminergic neurons and represent a model for neuronal differentiation were cultured on collagen-coated fibres to evaluate cell response dependence on substrate topography. Cell adhesion, viability and proliferation, as well as dopamine production were evaluated after three days since seeding. Cell differentiation was examined in terms of neurite number, orientation and length 6 days after administration of nerve growth factor (NGF). Results showed that proliferating PC12 cells secreted a higher quantity of dopamine on fibres with respect to control cultures and as a result, a possible use of PHB fibres was considered for cell transplantation in the central nervous system when local production of dopamine is impaired. Differentiated PC12 cells were characterized by highly aligned and longer neurites on parallel PHB fibres with respect to random fibres, thereby demonstrating the suitability of parallel PHB fibres for further studies in peripheral nervous system regeneration. . Immunofluorescent staining of b3-tubulin as an early marker of PC12 differentiation on PHB random (a, b) and parallel fibres (c, d). Low magnification images are on top row whereas high magnification images are on bottom row. Parallel fibre axis is oriented as yellow arrows PC12 neuron-like cell response to electrospun poly(3-hydroxybutyrate) substrates
A process of solid state fermentation (SSF) on tomato pomace was developed with the white-rot fun... more A process of solid state fermentation (SSF) on tomato pomace was developed with the white-rot fungi Pleurotus ostreatus and Trametes versicolor, using sorghum stalks as support. Operative parameters (humidity, water activity, and size of substrate particles) guaranteeing a good colonization of tomato pomace by both fungi were defined and conditions for production at high titers of the industrially relevant enzymes laccase, xylanase and protease were identified. Significant laccase activity levels (up to 36 U g−1 dry matter) were achieved without any optimization of culture conditions, neither by nutrient addition nor by O2 enrichment. Furthermore, protease activity levels up to 34,000 U g−1 dry matter were achieved, being higher than those reported for the fungi typically considered as the best protease producers such as Aspergillus strains. Moreover, as one of the most significant results of this study, analysis of P. ostreatus tomato SSF samples by zymogram revealed two bands with laccase activity which had not been detected so far.
This study was aimed at developing a process of solid state fermentation (SSF) with the fungi Ple... more This study was aimed at developing a process of solid state fermentation (SSF) with the fungi Pleurotus ostreatus and Trametes versicolor on apple processing residues for wastewater decolorization. Both fungi were able to colonize apple residues without any addition of nutrients, material support or water. P. ostreatus produced the highest levels of laccases (up to 9 U g À1 of dry matter) and xylanases (up to 80 U g À1 of dry matter). A repeated batch decolorization experiment was set up with apple residues colonized by P. ostreatus, achieving 50% decolorization and 100% detoxification after 24 h, and, adding fresh wastewater every 24 h, a constant decolorization of 50% was measured for at least 1 month. A continuous decolorization experiment was set up by a packed-bed reactor based on colonized apple residues achieving a performance of 100 mg dye L À1 day À1 at a retention time of 50 h.
The influence of novel nanostructured anisotropically electrospun poly(hydroxy butyrate) matrices... more The influence of novel nanostructured anisotropically electrospun poly(hydroxy butyrate) matrices on skeletal and cardiac muscle-like cell proliferation and differentiation was investigated, in comparison with isotropic and no-topographically cues-provided substrates. After the matrix characterization, in terms of surface SEM imaging and mechanical properties, cell differentiation on the different substrates was evaluated. Myogenin and F-actin staining at several differentiation time-points suggested that aligned nanofibers promote differentiation of both cell types. Moreover, quantitative parameters for each cell line are provided to clarify which aspects of the differentiation process are influenced by the different matrix topographies.
This study aims at investigating the behavior in terms of the proliferation and skeletal muscle d... more This study aims at investigating the behavior in terms of the proliferation and skeletal muscle differentiation capability of two myoblastic cell lines, C2C12 and H9c2, on both isotropic and anisotropic electrospun nanofibrous poly(hydroxybutyrate) (PHB) scaffolds, as well as on PHB films and polystyrene controls. After a careful characterization of the matrices in terms of surface morphology, surface roughness and mechanical properties, the proliferation rate and the capability of the two cell lines to form skeletal myotubes were evaluated. Genetic analyses were also performed in order to assess the differentiation level of the cells on the different substrates. We demonstrated that the aligned nanofibrous mesh decreases the proliferation activity and provides a higher differentiative stimulus. We also clarified how the nanofibrous substrate influences myotube formation, and quantified a series of myotube-related parameters for both C2C12 and H9c2 cells.
While most of the studies on molecular machines have been performed in solution, interfacing thes... more While most of the studies on molecular machines have been performed in solution, interfacing these supramolecular systems with solid-state nanostructures and materials is very important in view of their utilization in sensing components working by chemical and photonic actuation. Host polymeric materials, and particularly polymer nanofibers, enable the manipulation of the functional molecules constituting molecular machines and provide a way to induce and control the supramolecular organization. Here, we present electrospun nanocomposites embedding a self-assembling rotaxane-type system that is responsive to both optical (UV-vis light) and chemical (acid/base) stimuli. The system includes a molecular axle comprised of a dibenzylammonium recognition site and two azobenzene end groups and a dibenzo[24]crown-8 molecular ring. The dethreading and rethreading of the molecular components in nanofibers induced by exposure to base and acid vapors, as well as the photoisomerization of the azobenzene end groups, occur in a similar manner to what observed in solution. Importantly, however, the nanoscale mechanical function following external chemical stimuli induces a measurable variation of the macroscopic mechanical properties of nanofibers aligned in arrays, whose Young's modulus is significantly enhanced upon dethreading of the axles from the rings. These composite nanosystems show therefore great potential for application in chemical sensors, photonic actuators, and environmentally responsive materials.
Journal of Tissue Engineering and Regenerative Medicine, 2012
In the last decade, the importance of topographic properties of extracellular environments has be... more In the last decade, the importance of topographic properties of extracellular environments has been shown to be essential to addressing cell response, especially when replacing damaged tissues with functional constructs obtained in vitro. In the current study, densely packed sub-micron poly (3-hydroxybutyrate) (PHB) fibres were electrospun with random and parallel orientations. PC12 pheochromocytoma cells that mimic central dopaminergic neurons and represent a model for neuronal differentiation were cultured on collagen-coated fibres to evaluate cell response dependence on substrate topography. Cell adhesion, viability and proliferation, as well as dopamine production were evaluated after three days since seeding. Cell differentiation was examined in terms of neurite number, orientation and length 6 days after administration of nerve growth factor (NGF). Results showed that proliferating PC12 cells secreted a higher quantity of dopamine on fibres with respect to control cultures and as a result, a possible use of PHB fibres was considered for cell transplantation in the central nervous system when local production of dopamine is impaired. Differentiated PC12 cells were characterized by highly aligned and longer neurites on parallel PHB fibres with respect to random fibres, thereby demonstrating the suitability of parallel PHB fibres for further studies in peripheral nervous system regeneration. . Immunofluorescent staining of b3-tubulin as an early marker of PC12 differentiation on PHB random (a, b) and parallel fibres (c, d). Low magnification images are on top row whereas high magnification images are on bottom row. Parallel fibre axis is oriented as yellow arrows PC12 neuron-like cell response to electrospun poly(3-hydroxybutyrate) substrates
A process of solid state fermentation (SSF) on tomato pomace was developed with the white-rot fun... more A process of solid state fermentation (SSF) on tomato pomace was developed with the white-rot fungi Pleurotus ostreatus and Trametes versicolor, using sorghum stalks as support. Operative parameters (humidity, water activity, and size of substrate particles) guaranteeing a good colonization of tomato pomace by both fungi were defined and conditions for production at high titers of the industrially relevant enzymes laccase, xylanase and protease were identified. Significant laccase activity levels (up to 36 U g−1 dry matter) were achieved without any optimization of culture conditions, neither by nutrient addition nor by O2 enrichment. Furthermore, protease activity levels up to 34,000 U g−1 dry matter were achieved, being higher than those reported for the fungi typically considered as the best protease producers such as Aspergillus strains. Moreover, as one of the most significant results of this study, analysis of P. ostreatus tomato SSF samples by zymogram revealed two bands with laccase activity which had not been detected so far.
This study was aimed at developing a process of solid state fermentation (SSF) with the fungi Ple... more This study was aimed at developing a process of solid state fermentation (SSF) with the fungi Pleurotus ostreatus and Trametes versicolor on apple processing residues for wastewater decolorization. Both fungi were able to colonize apple residues without any addition of nutrients, material support or water. P. ostreatus produced the highest levels of laccases (up to 9 U g À1 of dry matter) and xylanases (up to 80 U g À1 of dry matter). A repeated batch decolorization experiment was set up with apple residues colonized by P. ostreatus, achieving 50% decolorization and 100% detoxification after 24 h, and, adding fresh wastewater every 24 h, a constant decolorization of 50% was measured for at least 1 month. A continuous decolorization experiment was set up by a packed-bed reactor based on colonized apple residues achieving a performance of 100 mg dye L À1 day À1 at a retention time of 50 h.
The influence of novel nanostructured anisotropically electrospun poly(hydroxy butyrate) matrices... more The influence of novel nanostructured anisotropically electrospun poly(hydroxy butyrate) matrices on skeletal and cardiac muscle-like cell proliferation and differentiation was investigated, in comparison with isotropic and no-topographically cues-provided substrates. After the matrix characterization, in terms of surface SEM imaging and mechanical properties, cell differentiation on the different substrates was evaluated. Myogenin and F-actin staining at several differentiation time-points suggested that aligned nanofibers promote differentiation of both cell types. Moreover, quantitative parameters for each cell line are provided to clarify which aspects of the differentiation process are influenced by the different matrix topographies.
This study aims at investigating the behavior in terms of the proliferation and skeletal muscle d... more This study aims at investigating the behavior in terms of the proliferation and skeletal muscle differentiation capability of two myoblastic cell lines, C2C12 and H9c2, on both isotropic and anisotropic electrospun nanofibrous poly(hydroxybutyrate) (PHB) scaffolds, as well as on PHB films and polystyrene controls. After a careful characterization of the matrices in terms of surface morphology, surface roughness and mechanical properties, the proliferation rate and the capability of the two cell lines to form skeletal myotubes were evaluated. Genetic analyses were also performed in order to assess the differentiation level of the cells on the different substrates. We demonstrated that the aligned nanofibrous mesh decreases the proliferation activity and provides a higher differentiative stimulus. We also clarified how the nanofibrous substrate influences myotube formation, and quantified a series of myotube-related parameters for both C2C12 and H9c2 cells.
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