Thermal compression and characterization of three-dimensional nonwoven PETmatrices as tissue engineering scaffolds

Nonwoven fibrous matrices have been widely used as scaffolds in tissue engi neering, and modification of microstructure of these matrices is needed to organize cells in three-dimensional space with spatially balanced prolifera tion and differentiation required for functional tissue development. The me thod of thermal compression of nonwoven polyethylene terephthalate (PET) fa brics was developed and key parameters of temperature, pressure, and compre ssion duration were evaluated in this study. The permanent deformation was obtained at elevated temperature under pressure and the viscoelastic compre ssional behaviors were observed, characterized by a distinct apparent modul us change in glass transition temperature region. A liquid extrusion method was further employed to analyze both pore size and its distribution for ma trices with porosity ranging From 84 to 93%. It is also found that a more u niformly distributed pore size was resulted from thermal compression and th e isotropic nature of nonwoven Fabrics was preserved because of the proport ional reduction of the pore by compression. The thermally compressed fabric matrices with two different pore sizes (15 and 20 mum in pore radius) were used to culture human trophoblast ED27 and NIH 3T3 cells. It was found tha t cells cultured in the different pore-size PET matrices had different cell spatial organization and proliferation rates. The smaller pores in the mat rix allowed cells to spread better and proliferate faster, while cells in t he larger pores tended to form large aggregates and had lower proliferation rate. The thermal compression technique also can be applied to other synth etic fibrous matrices including biodegradable polymers used in tissue engin eering to modify the microstructure according to their viscoelastic propert ies. (C) 2001 Elsevier Science Ltd. All rights reserved.