Nanostructured ECM-like biointerfaces for regenerative medicine applications

Abstract

Event Abstract Back to Event Nanostructured ECM-like biointerfaces for regenerative medicine applications Damien Lefèvre1, Christine Dupont-Gillain1 and Sophie Demoustier-Champagne1 1 Université Catholique de Louvain, Institute of Condensed Matter and Nanosciences (Bio & Soft Matter), Belgium Regenerative medicine drives the development of biointerfaces artificially recreating down to the nanoscale the conditions guiding cell fate in vivo. As the complex interplay of topographical, mechanical, biochemical and physicochemical stimuli driving cell proliferation and differentiation is provided in nature through the extracellular matrix [ECM], current trends in tissue engineering focus on the development of biointerfaces mimicking the native ECM. Here, we report on the production of biomimetic interfaces to support regenerative medicine strategies. With the ECM nanofibrillar structure set as standard, our engineered ECM-like matrices were designed as networks consisting of intersected nanotubes (Fig 1). While ensuring appropriate porosity, such a network offers the opportunity to store a bioactive cargo (e.g., growth factor, anti-inflammatory drug, etc.) within the constituting hollow nanotubes. When choosing the components of these nanotubes, a compromise between biomimetism, biocompatibility and adequate mechanical stability was reached, in a way to switch from soft nanoenvironments closely mimicking the native ECM towards more robust self-supported 3D architectures. Biomacromolecules originating from the native ECM, i.e. collagen [Col] and hyaluronic acid [HA], were therefore combined with a framework of rigid and conductive polymers or ceramic strengthening agents to yield nanotubes with a core-shell structure. The strategy developed for the preparation of these matrices consists in a combination of the hard-templating method with bottom-up synthesis processes[1]. Track-etched polycarbonate membranes [PC] featuring a network of intersected nanopores were filled by a combination of the layer-by-layer [LbL] assembly of Col and HA[2], either with the (electro)polymerization of a rigid conductive polymer (polypyrrole, [PPy])[3] or the adsorption of strengthening agents (e.g., silicon dioxide nanoparticles), to build hybrid nanostructures. Electron microscopy data show the production, after selective dissolution of the supporting template, of mechanically-strengthened ECM-like nanostructures (Fig 2). The chemical composition of these biointerfaces was determined using energy dispersive X-rays and time-of-flight secondary ion mass spectrometry while the mechanical properties of their constituting nanotubes were probed using atomic force microscopy nanoindentation tests. Adhesion and proliferation assays involving the seeding of MC3T3-E1 pre-osteoblasts on the produced biointerfaces will yield indications regarding the potentialities of our engineered biomaterials to efficiently support cell proliferation and differentiation without inducing cytotoxic effects. In conclusion, as an original contribution to the synthesis of biointerfaces able to regulate cell fate for regenerative medicine, we have developed biointerfaces mimicking the native ECM. Applying bottom-up synthesis processes within a templating membrane featuring intersected nanopores offers a highly versatile approach for the creation of multifunctional 3D biointerfaces whose chemical composition as well as mechanical and conductive properties can be tailored at will. Engineered ECM-like biointerfaces offering such a wide range of tailored stimuli are expected to open opportunities to guide the differentiation of cells, including stem cells, towards a desired phenotype. This research has been funded by the Interuniversity Attraction Poles Program initiated by the Belgian Science Policy Office (IAP-PAI P7/05).