Design of cyclic tissue engineering bioreactor based on alginate hydrogel responses to the stress of compression...

Effective design of bioreactors for soft tissue engineering requires a precise understanding of how biomimetic mechanical stimuli affect the behaviors of scaffolds. This work investigates the influence of cartilage-mimetic compressor head geometry and forces on the mechanical and rheological properties of alginate hydrogels under cyclic compression. We applied controlled strains using four distinct piston head shapes, i.e. flat-surface for uniform pressure, curved-edge for non-uniform pressure, spherical to simulate point loads, and sectional to generate partial and complex pressures, and compared experimental Texture Profile Analysis (TPA) with Finite Element Analysis (FEA) simulations. The results demonstrate that the piston's surface geometry is a critical determinant of stress distribution, stiffness, and energy dissipation within the gel. Our FEA model accurately predicted the von Mises and hydrostatic stresses observed experimentally, validating them as reliable designs. This integrated approach provides a robust framework for developing biomimetic compression-stimulation bioreactors for applications in cartilage and other soft tissue engineering.