Dynamic formation of oriented patches in chondrocyte cell cultures

Myoblast alignment on 2D wavy patterns: dependence on feature characteristics and cell-cell interaction

In this study, we investigate the effects of micron-scale surface patterns on the alignment of individual cells and groups of cells. Using a simple replication molding process we produce a number of micron-scale periodic wavy patterns with different pitch and depth. We observe C2C12 cells as they grow to confluence on these patterns and find that, for some geometries, cell-cell interaction leads to global alignment in a confluent culture when individual cells would not align on the same pattern. Three types of alignment behavior are thus defined: no alignment, immediate alignment, and alignment upon confluence. To further characterize this response, we introduce a non-dimensional parameter that describes the aligning power of a periodic pattern based on its geometry. The three types of alignment behavior can be distinguished by the value of the alignment parameter, and we identify values at which the transitions in alignment behavior occur. Applying this parameter to data from the current and several earlier studies reveals that the parameter successfully describes substrate aligning power over a wide range of length scales for both wavy and grooved features.

A phase-field model for articular cartilage regeneration in degradable scaffolds

Degradable scaffolds represent a promising solution for tissue engineering of damaged or degenerated articular cartilage which due to its avascular nature, is characterized by a low self-repair capacity. To estimate the articular cartilage regeneration process employing degradable scaffolds, we propose a mathematical model as the extension of Olson and Haider's work (Int. J. Pure Appl. Math. 53:333-353, 2009). The simulated tissue engineering procedure consists in (i) the explant of a cylindrical sample, (ii) the removal of the inner core region, and (iii) the filling of the inner region with hydrogels, degradable scaffolds enriched with nutrients, such as oxygen and glucose. The phase-field model simulates the cartilage regeneration process at the scaffold-cartilage interface. It embeds reaction-diffusion equations, which are used to model the nutrient and regenerated extracellular matrix. The equations are solved using an unconditionally stable hybrid numerical scheme. Cartilage repair processes with full-thickness defects, which are controlled by properties of hydrogel materials and cartilage explant culture based on biological interest are observed. The implemented mathematical model shows the capability to simulate cartilage repairing processes, which can be virtually controlled evaluating hydrogel and cartilage material properties including nutrient supply and defected magnitude. In particular, the adopted methodology is able to explain the regeneration time of cartilage within hydrogel environments. With the numerical scheme, the numerical simulations are demonstrated for the potential improvement of hydrogel structures.