Functional cardio-biomaterials

Titanium as well as carbon based biomaterials, seem to be good candidates for future blood-contact applications. Bio-materials such as: Ti, Ti+DLC, TiN; Ti(C, N) with higher carbon concentration and DLC (diamond like carbon) were under examinations. Trials on surface modification of PU (polyurethane) substrate using ion mill were performed. Materials were deposited as thin films by the hybrid pulsed laser deposition (PLD) technique to examine the influence of the fabricated surfaces on cell behavior. The metallic titanium as a target was used for titanium based-film and graphite one for DLC. Phase content of deposited films was controlled by the flowing gas mixture of Ar+N₂ and Ar+N₂+C₂H₂ type in the reactive chamber. Sputtering of graphite was carried out in Ar atmosphere. The kinetic energy of the evaporated particles was controlled by application of variation of different reactive and non reactive atmospheres during deposition. Transmission electron microscopy (TEM) was used to reveal structure dependence on specific atmosphere in the reactive chamber. The measurement of the strength of bonds between biomaterials and cells is a major challenge in cellular biology since it allows for the identification of different species in adhesion phenomena. The biomaterial examinations were performed in static conditions with Dictyostelium discoideum cells and then subjected to a dynamical test to observe the cell detachment kinetics. For a given cell, detachment occurs for critical stress values caused by the applied hydrodynamic pressure above a threshold which depends on cell size and physicochemical properties of the substrate, but it is not affected by depolymerization of the actin and tubulin cytoskeleton. Tests revealed differences in behavior in respect to the applied coating material. The strongest cell-biomaterial interaction was observed for the carbon-based materials compared to the titanium and titanium nitride.

A surface fuctionalization was realized by: (i) fabrication of migration channels by laser ablation, (ii) electrospinning and (iii) deposition of multilayer film from polyelectrolites. A goal of the performed research was formation of scaffolds for bio-mimetic coatings. Surface morphology examinations and biomedical studies on porous and semi-porous materials with application of human endothelial cells HUVEC line were performed by application of confocal laser scanning microscopy (CLSM).