Improving cell adhesion by designing hydrogel-based coatings for tissue engineering

Polymeric hydrogels are an important class of functional soft materials composed of a large variety of neutral or charged hydrophilic macromolecules cross-linked chemically or physically in an aqueous environment. The water-rich nature of hydrogels resembles biological tissues opening up opportunities for their application in biomedical areas, such as tissue engineering. However, the mere presence of a matrix for cell growth is often not sufficient for a good cell adhesion and proliferation; this requires other components, which provide additional functionalities, for example: improve cell adhesion, stimulate ossification process, provide antibacterial protection, etc (polymers, nano- and micro- particles, biological molecules, such as growth factors, enzymes, DNA or RNA). That stimulates development of hydrogel-based hybrid materials incorporating both organic and inorganic components. Hydrogel-based hybrid materials are emerging as a very potent and promising class of materials due to their diverse properties, which are proved to be a viable tool for tissue engineering applications allowing to improve cell adhesion and formation of the extracellular matrix (ECM) and tissue regeneration. Novel processes of hydrogel matrix synthesis, incorporation of inorganic particles and bioactive molecules as well as assembly of new particle-like surfaces are developed in this work to improve and facilitate cell adhesion and proliferation. Specifically: (1) hydrogel modification via thermal annealing process is conducted, which changes pore sizes, mechanical properties, fibril clustering, and the morphology of hydrogels from mesh to fibers; (2) design of composite Gellan Gum (GG) is pursued by functionalizing it with carbon nanotubes, which result in a significant improvement of cell adhesion; (3) functionalization of hydrogels with calcium and magnesium carbonate minerals is performed for hydroxyapatite (HA) produced by cells on composite GG hydrogels; (4) investigation of cell adhesion on CaCO3 microparticles on the surface of composite alginate hydrogels with distinct local nano- and macro- scale mechanical properties is carried out; (5) novel hybrid materials are designed by shrinking inorganic/organic nanostructured alginate/vaterite spheroids modified with alkaline phosphatase for acceleration of ossification. Analysis of described above samples and phenomena is based on architectural, mechanical, and chemical properties, where the interaction of cells with the samples and their further behavior on the surface remains an important factor. 20 To prove that cells proliferate and perform ECM biosynthesis on synthesized biomaterials, osteoblast cells are selected, which form an ECM consisting of collagen and HA. Therefore, we study a possibility to enhance the cell ossification by functionalizing the hydrogel matrix by carbonate-based particles with various size, shape, composition, and concertation. As a result, a possibility to enhance the ECM formation is investigated by designing tissue engineering structures, which are also applied to study cell adhesion on the colloidal particles. Our results emphasize the added value of hydrogel-based hybrid materials and approaches, particularly involving functionalization by microparticles and bioactive molecules. Such new materials are envisioned to find applications in tissue engineering, biomedicine, and biology