Influence of biological matrix and artificial electrospun scaffolds on proliferation, differentiation and trophic factor synthesis of rat embryonic stem cells.

Abstract Two-dimensional vs three-dimensional culture conditions, such as the presence of extracellular matrix components, could deeply influence the cell fate and properties. In this paper we investigated proliferation, differentiation, survival, apoptosis, growth and neurotrophic factor synthesis of rat embryonic stem cells (RESCs) cultured in 2D and 3D conditions generated using Cultrex® Basement Membrane Extract (BME) and in poly-( l -lactic acid) (PLLA) electrospun sub-micrometric fibres. It is demonstrated that, in the absence of other instructive stimuli, growth, differentiation and paracrine activity of RESCs are directly affected by the different microenvironment provided by the scaffold. In particular, RESCs grown on an electrospun PLLA scaffolds coated or not with BME have a higher proliferation rate, higher production of bioactive nerve growth factor (NGF) and vascular endothelial growth factor (VEGF) compared to standard 2D conditions, lasting for at least 2 weeks. Due to the high mechanical flexibility of PLLA electrospun scaffolds, the PLLA/stem cell culture system offers an interesting potential for implantable neural repair devices

Electrospun nanofibrous scaffolds: potentialities and applications in tissue engineering

Development of artificial scaffolds for tissue engineering is a key area of research in the regenerative medicine field. In the in vivo microenvironment, mammalian cells are surrounded by a natural fibrillar extracellular matrix whose elements are typically organized in the nanometer scale. Progresses in nanothechnologies allowed to develop biomimetic nanofibrous scaffolds that were demonstrated to play a crucial role in controlling cell migration, proliferation, differentiation, and other complex tissue functions. This presentation will focus on the design and application of nanofibrous scaffolds fabricated through the electrospinning technology, an increasingly popular process to produce non-woven textiles composed of fibres with diameters ranging from hundreds of nanometers to several tenths of microns. The great interest towards this technology arises from the simplicity of the set-up, the cost-effectiveness of the apparatus and versatility, that allows to produce electrospun materials possessing a wide range of chemical-physical properties. In addition, it is also possible to obtain fibres from polymer blends or drug-loaded and particle-loaded fibres as well as \u201ccomposite\u201d non-woven textiles by concomitantly electrospin different materials. Another interesting advantage of electrospinning is the possibility to tune mesh micro/nano-architecture - in terms of fibre dimension, fibre surface porosity and fibre orientation - by tuning process parameters. This presentation will give an overview of frontier-research on biomimetic electrospun scaffolds and will point out some of the current industrial applications, as well as future potentiality of electrospun scaffolds in the biomedical field

Cell delivery for regenerative medicine by using bioresorbable polymers

For regenerative medicine, the development of an optimal biomaterial system to deliver cells is crucial to precisely locate cells in the target site while preserving cell activity and function. In addition, the cell delivery construct should have the same instructive role as the extracellular microenvironment that naturally surrounds cells within a tissue. This chapter presents an overview of main concepts for the design of bioresorbable constructs for cell delivery and tissue regeneration, namely, types of polymers with recognized biocompatibility and bioresorbability, mechanical properties, structural architecture, and mass transport of the construct, as well as incorporation of biochemical and biophysical cues to provide instructive cell signaling and scaffold bioactivity. Regulatory and clinical aspects are mentioned at the end as they are important to ensure commercial success for these cutting-edge products

Polymers from biocatalysis: materials with a broad spectrum of physical properties

Copolymers of omega-pentadecalactone (PDL) with epsylon-caprolactone, valerolactone, dioxanone and trimethylenecarbonate synthesized by biocatalysis show rather uncommon crystallization behavior, namely cocrystallization of the monomer units that leads to highly crystalline copolymers over the whole composition range. Hydrophilic/hydrophobic balance can be adjusted by a suitable choice of the comonomer and of composition, leading to materials with tunable hydrolytic degradation rate for environmental and biomedical applications. Copolyestercarbonates, copolyesteramides and polyol-containing copolyesters synthesized by lipase-catalysed polycondensation show strongly composition dependent physical properties, that can be easily tailored by composition control and cover the whole range from hard solid materials down to gluelike substance

Polymers from biocatalysis: Materials with a broad spectrum of physical properties

none3Copolymers of omega-pentadecalactone (PDL) with epsylon-caprolactone, valerolactone, dioxanone and trimethylenecarbonate synthesized by biocatalysis show rather uncommon crystallization behavior, namely cocrystallization of the monomer units that leads to highly crystalline copolymers over the whole composition range. Hydrophilic/hydrophobic balance can be adjusted by a suitable choice of the comonomer and of composition, leading to materials with tunable hydrolytic degradation rate for environmental and biomedical applications. Copolyestercarbonates, copolyesteramides and polyol-containing copolyesters synthesized by lipase-catalysed polycondensation show strongly composition dependent physical properties, that can be easily tailored by composition control and cover the whole range from hard solid materials down to gluelike substancesTitolo della collana: ACS Symposium SeriesnoneM. Scandola; M.L. Focarete; R.A. GrossM. Scandola; M.L. Focarete; R.A. Gros

Biocotalysis provides polymers with a broad range of solid-state properties

High molecular weight polymers that cannot be obtained by chemical routes are easily synthesized by lipase-catalyzed polymerization. Some lipases such as Candida antarctica Lipase B, when used in ring opening polymerization, allow incorporation of different monomers along the chain leading to copolymers with defined composition and microstructure. Control over microstructure is critical to the ultimate goal of tailoring the physical, mechanical, and biological properties of copolymers. Hydrophilic/hydrophobic balance can be adjusted by a suitable choice of the two monomers and of composition, leading to materials with tunable hydrolytic degradation rate for environmental and biomedical applications. Copolymers of omega-pentadecalactone with epsilon-caprolactone, valerolactone, dioxanone and trimethylenecarbonate are highly crystalline over the whole composition range, an unusual behavior due to co-crystallization of the co-monomer units. Copolyestercarbonates, copolyesteramides and polyol-containing copolyesters synthesized by lipase-catalysed polycondensation show strongly composition dependent physical properties, that can be easily tailored by composition control and cover the whole range from hard solid materials down to gluelike substances