Nano-colloid printing of functionalised PLA-b-PEO copolymers: Tailoring the surface pattern of adhesive motif and its effect on cell attachment

n this study, we investigate the preparation of surface pattern of functional groups on poly(lactide) (PLA) surfaces through the controlled deposition of core-shell self-assemblies based on functionalized PLA-b-PEO amphiphilic block copolymers from selective solvents. Through grafting RGDS peptide onto the functionalized copolymer surface, the presented approach enables to prepare PLA surfaces with random and clustered spatial distribution of adhesive motifs. The proposed topography of the adhesion motif was proved by atomic force microscopy techniques using biotin-tagged RGDS peptide grafted on the surface and streptavidin-modified gold nanospheres which bind the tagged RGDS peptides as a contrast agent. The cell culture study under static and dynamic conditions with MG63 osteosarcoma cell line showed that the clustered distribution of RGDS peptides provided more efficient initial cell attachment and spreading, and resistance to cell detachment under dynamic culture compared to randomly distributed RGDS motif when with the same average RGDS peptide concentration

Chondrogenic potential of macroporous biodegradable cryogels based on synthetic poly(alpha-amino acids)

In this study, the potential of highly porous hydrogels based on biodegradable synthetic poly(alpha-amino acids) to support proliferation and chondrogenesis of human dental pulp stem cells (hDPSCs) was investigated. Covalently crosslinked gels with permanent pores were formed under cryogenic conditions by free-radical copolymerization of poly[N-5-(2-hydroxyethyl)-L-glutamine-stat-N-5-(2-methacryloyl-oxy-ethyl)- L-glutamine] (PHEG-MA) with 2-hydroxyethyl methacrylate (HEMA) and N-propargyl methacrylamide (PrMAAm) as minor co-monomers. PrMAAm provided alkyne groups for modifying the gels with cell-supporting moieties (RGDS peptides) by the azide-alkyne "click"-reaction. Two types of gels with different compressive moduli were prepared. Each type was modified with two different concentrations of RGDS peptide. X-ray computed nanotomography (nanoCT) was used to visualize and analyze the 3D-structure of the cryogels. It was shown that modifying the PHEG-MA cryogels within the range of RGDS concentrations examined here had a positive effect on the proliferation of hDPSCs. Immunofluorescence staining for collagen type 2 and aggrecan proved that there was differentiation of hDPSCs into chondrocytes

Micro- and nanopatterned surfaces for guided adhesion, growth and phenotypic maturation of cells

Micropatterned surfaces were created by UV light-irradiation of polytetrafluoroethylene through a metallic mask, by successive plasma polymerization of acrylic acid and 1,7-octadiene, or by creation of prominences and grooves by deposition of fullerenes C60 through a metallic mask. All these surface types were capable of inducing regionally-selective adhesion, proliferation and phenotypic maturation of vascular endothelial cells, vascular smooth muscle cells or human bone-derived MG 63 cells. Nanopatterned surfaces created by tethering GRGDSG oligopeptides through polyethylene oxide chains on a polymeric surface promoted spreading, formation of focal adhesion plaques and DNA synthesis in vascular smooth muscle cells. Surfaces nanopatterned with nanocrystalline diamond gave good support for the adhesion, growth and metabolic activity of osteoblast-like MG 63 cells