Lifli kolajen içeren peg hidrojellerdeki hücre hareketinin dinamiği

Understanding the migratory behavior of cells on biomaterials plays a key role to advance scaffold composition for studying cell-substrate interactions. Biomaterials that emulate the identical biochemical cues and mechanical niche of naturally occurring substrates are desired to develop functional scaffolds. Hydrogels are directly utilized as scaffolds because of their resemblance to natural tissue and porous structure that as an advantage for sufficient transport of nutrients, gases and removal of metabolic waste. Cell motility is a complex dynamics process in multicellular organisms, and depends on several factors, such as adhesion strength, functional groups of extracellular matrix, neighbor cells, external signals, elasticity of medium, and the organization of cytoskeleton. Despite the recent studies on understanding single-cell viability and encapsulation in hydrogels, inadequate characterization of motility and difficulty to mimic the physical properties of extracellular matrix limit the development of advanced scaffolds. In this thesis, we prepared polyethylene glycol (PEG) hydrogels that contain highly flexible and long collagen fibers that was characterized by scanning electron microscope (SEM), fluorescence microscopy, and tracking fiber movement. Hydrogel scaffold preserved the elastic properties of fibrous collagen, therefore provided a compliant medium for studying cellular dynamics. Moreover, we used custom image processing tool and single-cell tracking method to determine cell trajectories at high spatio-temporal resolution, and compute the motility parameters such as cell persistence, mean square displacement and diffusion constant. As a result, weak contractive forces applied to stretchable collagens on soft hydrogels resulted in slow motility. Moreover, angular displacement results demonstrated that single-cell movement at short time scales was isotropic but appeared to have a slight increase of persistence at angles of 0° to 180° which corresponds to the direction parallel along the axis of fibrous collagens on hydrogels. We envisioned that trajectory analysis explained here provides a quantitative description for studying cell dynamics on biomaterials and can be used to study the effect of various chemical and biological functional groups of hydrogels on cell motility.