ElsevierVallés Lluch, A.; Arnal Pastor, MP.; Martínez Ramos, C.; Vilariño Feltrer, G.; Vikingsson, L.; Castells Sala, C.; Semino, CE.... (2013). Combining self-assembling peptide gels with three-dimensional elastomer scaffolds. Acta Biomaterialia. 9 (12) Abstract: Some of the problems raised by the combination of porous scaffolds and self-assembling peptide (SAP) gels as constructs for tissue engineering applications are for the first time addressed. Scaffolds of poly(ethyl acrylate) and the SAP gel RAD16-I were employed. The in situ gelation of the SAP gel inside the pores of the scaffolds was studied. The scaffold-cum-gel constructs were characterized morphologically, physico-chemically and mechanically. The possibility of incorporating an active molecule (bovine serum albumin, taken here as a model molecule for others) in the gel within the scaffold's pores was assessed, and the kinetics of its release in PBS was followed. Cell seeding and colonization of these constructs was preliminary studied with L929 fibroblasts and checked afterwards with sheep adipose-tissue derived stem cells (ASCs) intended for further preclinical studies. Static (conventional) and dynamically assisted seedings were compared for bare scaffolds and the scaffoldcum-gel constructs. The SAP gel inside the pores of the scaffold significantly improved the uniformity and density of cell colonization of the 3D structure. These constructs could be of use in different advanced tissue engineering applications where, apart from a cell-friendly ECM-like aqueous environment, a larger-scale three-dimensional structure able to keep the cells in a specific place, give mechanical support and/or conduct spatially the tissue growth could be required. COMBINING SELF-ASSEMBLING PEPTIDE GELS WITH 3D ELASTOMER SCAFFOLDSA. AbstractSome of the problems raised by the combination of porous scaffolds and selfassembling peptide (SAP) gels as constructs for tissue engineering applications are for the first time addressed. Scaffolds of poly(ethyl acrylate) and the SAP gel RAD16-I were employed. The in situ gelation of the SAP gel inside the pores of the scaffolds was studied. The scaffold-cum-gel constructs were characterized morphologically, physicochemically and mechanically. The possibility of incorporating an active molecule (bovine serum albumin, taken here as a model molecule for others) in the gel within the scaffold's pores was assessed, and the kinetics of its release in PBS was followed. Cell intended for further preclinical studies. Static (conventional) and dynamically assisted seedings were compared for bare scaffolds and the scaffold-cum-gel constructs. The SAP gel inside the pores of the scaffold significantly improved the uniformity and density of cell colonization of the 3D structure. These constructs could be of use in different advanced tissue engineering applications where, apart from a cell-friendly ECM-like aqueous environment, a larger-scale three-dimensional structure able to keep the cells in a specific place, give mechanical support and/o...

A set of elastomeric scaffolds with a well defined porous structure was prepared with a template leaching procedure and coated with hyaluronic acid solutions. Depending on the coating process parameters the hyaluronic acid deposited on the pores had configurations ranging from thin disconnected aggregates to a thick continuous layer on the pore surface. The development of the coating layer was studied by scanning electron microscopy and the materials were subjected to dynamical and equilibrium swelling experiments in a water vapor ambient of fixed activity. The porosity change due to coating and to swelling of the coating layer were determined. The hyaluronic acid coating the pores has a different swelling capacity depending on the type of layer formed, as a consequence of the scaffold constraint and of the layer typology. These factors were investigated analytically by modifying the standard theory of gel swelling. An experimental quantity is introduced which reflects the constrainment build-up on gel swelling.

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Ischemia produced as a result of myocardial infarction might cause moderate or severe tissue death. Studies under development propose grafting stem cells into the affected area and we hypothesize that this mechanism could be enhanced by the application of a "bioactive implant. " The implant herein proposed consists of a thin porous elastomeric membrane, filled with self-assembling nanofibers and human subcutaneous adipose tissue derived progenitor cells. We describe the development and characterization of two elastomeric membranes: poly(ethyl acrylate) (PEA) and poly(caprolactone 2-(methacryloyloxy)ethyl ester) (PCLMA). Both are a good material support to deliver cells within a soft self-assembling peptide and are elastic enough to withstand the stresses arising from the heartbeat. Both developed composites (PEA and PCLMA, combined with self-assembling peptide) equally facilitate the propagation of electrical pulses and maintain their genetic profile of the seeded cells. Preliminary studies with small animal models suggest that, at short times, the bioimplant shows good adhesion with the myocardium. After three days cells loaded in the patch remain alive at the implanted site. We propose that the bioactive patch (elastomeric membranes with self-assembling peptide and cells) could increase the efficacy of future cardiac cell therapy by improving cell immobilization and survival at the affected site.

ElsevierArnal Pastor, MP.; Martínez Ramos, C.; Perez Garnes, M.; Monleón Pradas, M.; Vallés Lluch, A. (2013). Electrospun adherent-antiadherent bilayered membranes based on crosslinked hyaluronic acid for advanced tissue engineering applications. Materials Science and Engineering: C. 33 (7)

The performance of a composite environment with human umbilical vein endothelial cells (HUVECs) has been studied to provide an in vitro proof of concept of their potential of being easily vascularized. These cells were seeded in 1 mm thick scaffolds whose pores had been filled with a self-assembling peptide gel, seeking to improve cell adhesion, and viability of these very sensitive cells. The combination of the synthetic elastomer poly(ethyl acrylate), PEA, scaffold and the RAD16-I peptide gel provides cells with a friendly ECM-like environment inside a mechanically resistant structure. Immunocytochemistry, flow cytometry and scanning electron microscopy were used to evaluate the cell cultures. The presence of the self-assembling peptide filling the pores of the scaffolds resulted in a truly 3D nanoscale context mimicking the extracellular matrix environment, and led to increased cells survival, proliferation as well as developed cell-cell contacts. The combined system consisting of PEA scaffolds and RAD16-I, is a very interesting approach as seems to enhance endothelization, which is the first milestone to achieve vascularized constructs.

The interior of tissue engineering scaffolds must be vascularizable and allow adequate nutrients perfusion in order to ensure the viability of the cells colonizing them. The promotion of rapid vascularization of scaffolds is critical for thick artificial constructs. In the present study co-cultures of human endothelial and adipose tissue-derived stem cells have been performed in poly(ethyl acrylate) scaffolds with two different pore structures: grid-like (PEA-o) or sponge-like (PEA-s), in combination with a self-assembling peptide gel filling the pores, which aims to mimic the physiological niche. After 2 and 7 culture days, cell adhesion, proliferation and migration, the expression of cell surface markers like CD31 and CD90 and the release of VEGF were assessed by means of immunocytochemistry, scanning electronic microscopy, flow cytometry and ELISA analyses. The study demonstrated that PEA-s scaffolds promoted greater cell organization into tubular-like structures than PEA-o scaffolds, and this was enhanced by the presence of the peptide gel. Paracrine signaling from adipose cells significantly improved endothelial cell viability, proving the advantageous combination of this system for obtaining easily vascularizable tissue engineered grafts. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1523-1533, 2016.

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