The potential applications of aligned, conductive electrospun fibers have been widely studied in anisotropic tissue regeneration. In this study, aligned porous poly L-lactic acid fibers were obtained with electrospinning, then polypyrrole nanoparticles (PPy NPs) were coated onto the porous fibers with oxidation polymerization to prepare electrically conductive fibers with about 1.24 mu m of diameter, and their surface conductivity was about 50 mS. The results of L929 cell test showed that more than 55% of cells grew along the aligned porous fiber axis, confirming that the cell guidance of aligned porous fibers was better than that of non-porous fibers. The results of differentiated PC12 cells on porous fibers showed that the alignment degree of neurite outgrowth and average neurite length of the cells were 84% and 111 mu m, respectively, which were larger than those on the non-porous fibers. A primary mechanism was proposed to explain effect of these pores on cell/neurite adhesion and orientation along the aligned porous fibers. (C) 2015 Elsevier B.V. All rights reserved.