Alginate – chitosan – alginate multilayer hydrogel encapsulation systems were investigated for encapsulation of chondrocytes. Hydrogel is crosslinked due to ionic interaction between cationic chitosan and anionic alginate, and additionally by calcium ions. Two types of chitosan with molecular weight were investigated. Cells were encapsulated in two shape microcapsules, microbeads with diameter size 300 – 400 and 500 - 600 µm and fibres with diameter 500 - 600 µm. The work provides a detailed examination of the impact of the microencapsulation process on the growth of cells. The viability of chondrocytes can be influenced by the size of produced microcapsules, while the shape of microcapsules has no important significance on cell viability. The applied encapsulation methods do not contain harmful stages and create conducive conditions for cell growth. A possible application area of the developed system is dressing and regeneration of damaged joint cartilage.
A method of manufacturing hydrogel coatings designed to increase the hydrophilicity of polyurethanes (PU) is presented. Coatings were obtained from polyvinylpyrrolidone (PVP) by free radical polymerisation. The authors proposed a mechanism of a two-step grafting - crosslinking process and investigated the influence of reagent concentration on the coating’s physical properties - hydrogel ratio (HG) and equilibrium swelling ratio (ESR). A surface analysis of freeze-dried coatings using scanning electron microscopy (SEM) showed a highly porous structure. The presented technology can be used to produce biocompatible surfaces with limited protein and cell adhesive properties and can be applied in fabrication of number of biomedical devices, e.g. catheters, vascular grafts and heart prosthesis.
Because of excellent properties, similar to natural bone minerals, and variety of possible biomedical applications, hydroxyapatite (HAp) is a valuable compound among the calcium phosphate salts. A number of synthesis routes for producing HAp powders have been reported. Despite this fact, it is important to develop new methods providing precise control over the reaction and having potential to scale-up. The main motivation for the current paper is a view of continuous synthesis methods toward medical application of produced hydroxyapatite, especially in the form of nanoparticles.