Fabrication of highly porous tissue-engineering scaffolds using selective spherical porogens

Tissue engineering holds great promise as an alternative strategy to current treatment modalities of diseased or otherwise failed tissues. Most strategies of tissue engineering rely on three-dimensional porous scaffolds to mimic the natural extracellular matrix (ECM) as templates onto which cells attach, multiply, migrate and function. When cells are harvested from a donor and seeded, scaffolds facilitate the organization of these cells into a three-dimensional architecture, control cell behavior and subsequently direct the formation of organ-specific tissue. In view of its role, scaffold fabrication methods target the creation of highly porous and interconnected pore structures. Among the different scaffolds fabrication methods explored, solvent casting followed by precipitation or particulate leaching is one of the most straightforward methods. In this paper, we conducted a comparative study of two methods to prepare spherical porogens using poly(vinyl pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) as dispersing agents and we used these porogens to fabricate cylindrical porous scaffolds using a combination of pressure differential and solvent casting/particulate leaching method. Porogen particle size analyses showed that at 0.6% dispersing agent concentration, PVP produced smaller particles with narrower distribution (100-300 mum) than poly(vinyl alcohol) (100-500 mum) presumably due to the fast adsorption kinetics of the former. Scaffolds fabricated from PVP-stabilized porogens had higher open porosities and high pore interconnectivity than those based on porogens prepared using PVA stabilizer. Preliminary cell culture work also showed that scaffolds fabricated using PVP-stabilized porogens support attachment and spreading of human coronary artery smooth muscle cells (HCASMC) better than the PVA counterparts. This is the first time that such direct comparative studies on the porogen preparation methods and its effect on the scaffold porosity and cell attachment property is reported.