Surface alteration implications on potential use of semi-alicyclic polyimide as biomedical materials

Abstract

A semi-alicyclic polyimide (PI) is tested for hemocompatibility and cell growth purposes. The PI configuration in the presence of the adhesion proteins and interaction energy were computed showing a different stability dictated by the protein structure. PI film surface was altered by roughening with sand paper and the morphology was examined by atomic force microscopy (AFM). The recorded images show a conversion of the initial isotropic peak-to-valley height on the surface of the PI film into an anisotropic one made of microgrooves. This is supported by the amplitude distribution function, which for the pristine sample has a narrow peak (a single morphological entity), while upon surface roughening, it has two peaks, associated with tracks valleys and top of the hills. The shape parameters (skewness and kurtosis) related to the asymmetry of the surface departure and spread of the height distribution are significantly changed after altering of the PI surface. The values of the surface functional indexes and functional volume parameters are increasing upon the PI surface roughening. The changes in random character of the initial PI are also evidenced by autocorrelation cross-section profile. The altered PI film surface determines an anisotropic character of adhesion or spreading of blood and fibroblasts.