Preparation and Cell Compatibility Study of Porous Polymer Membranes

摘要

Porous polymer materials have been widely used as artificial organs, e.g. cornea, skin, liver, pancreas, and immune-isolating membrane etc. Both the surface and topographical properties of such a kind implant polymer materials or devices have to be specially designed to obtain suitable tissue compatibility. The reaction of cells to the topography of the substratum is an easy way to reveal and evaluate the compatibility of topographical materials in the cell level. The main objective of this paper is to study topographical induction and control of cell growth on porous polymer membranes. The open-celled PS and PU membranes, whose pores are interconnected and isotropic, were prepared by Thermally Induced Phase Separation (TIPS) technique (Fig.la). The effect of the polymer concentration, quenching rate, film-forming platforms and solvent-removing methods in TIPS process to the pore size and morphology were studied. Cell-compatible layer on PS surface was constructed by oxidizing with concentrated sulfuric acid for 5 to 60 min, resulting in the oxygen amount increasing and the hydrophilicity enhancing, hens, the adhesion and growth of endothelial cells (EC) were promoted. The time effect of cell growth on non-porous PS surface (oxidized for 15min) was studied. The cell morphology and activity in the 4th day were the best, which displayed as larger cell size, abundance cell plasm, shuttle-like morphology and confluent cell layer. With the time prolonged, the cell size decreased, the morphology changed to cobble stone, the contact inhibition emerged, and finally led to the apoptosis of the cells. Scratching groove on the surface showed pronounced control of EC growth. EC aligned the scratching groove with elongated cell shape, those in the groove could not grow and dead. The growth behavior of EC on porous polymer materials was initially studied, and the growing and spreading model of cells on porous surface was supposed for the first time (Fig.2). EC adhered and spread on the platform between the pores first. It was no influence of smaller pore (e.g. <5μm) to the growth and spreading of EC, one cell could cover the whole pore (Fig.lb). For the larger pore (e.g. 40μm), EC spread over the pore from peripheral edge to the center by the multiple cell coordination to form confluent cell layer. Retardant by the pores, the formation of confluent cell layer was slower on porous surface than that of on non-porous surface.