Osteoinducing scaffolds with multi-layered biointerface.

This study was aimed to design and characterise hybrid tissue-engineered constructs composed of osteoinducing polylactide-based scaffolds with multi-layered cellular biointerface for bone tissue reconstruction. Three-dimensional scaffolds with improved hydrophilic and osteoinducing properties were produced using the surface-selective laser sintering (SSLS) method. The designed scaffold pattern had dimensions of 8 × 8 × 2.5 mm and ladder-like pores (∼700 µm in width). Hyaluronic acid-coated polylactide microparticles (∼100 µm in diameter) were used as building blocks and water was used as the photosensitizer for SSLS followed by photocross-linking with Irgacure 2959 photoinitiator. Resulting scaffolds provided successful adhesion and expansion of human bone marrow mesenchymal stromal cells from a single-cell suspension. Induced calcium deposition by the cells associated with osteogenic differentiation was detected in 7-21 days of culturing in basal medium. The values were up to 60% higher on scaffolds produced at a higher prototyping speed under the experimental conditions. Innovative approach to graft the scaffolds with multi-layered cell sheets was proposed aiming to facilitate host tissue-implant integration. The sheets of murine MS-5 stromal cell line exhibited contiguous morphology and high viability in a modelled construct. Thus, the SSLS method proved to be effective in designing osteoinducing scaffolds suitable for the delivery of cell sheets.

Use of thermosensitive polymer material on the basis of N-isopropylacrylamide and N-tert-butylacrylamide copolymer in cell technologies.

We developed thermosensitive polymer substrates on the basis of N-isopropylacrylamide and N-tert-butylacrylamide co-polymer and studied their interaction with cultured substrate-dependent mammalian cells. It was shown that these polymers promote cell adhesion and proliferation at a level comparable to polystyrene treated for cell culturing and provide effective cell detachment after lowering culturing temperature below a critical level determined by phase transition temperature in aqueous solutions of polymers. A dependence of phase transition temperature on the ratio between N-isopropylacrylamide and N-tert-butylacrylamide was demonstrated. Differences in the dynamics of cell detachment from the surface of polymer substrates with various proportions between the components were shown.