Tissue engineering scaffolds require cell affinity, biodegradability, and desirable mechanical properties. Poly-L-lactic acid (PLLA) has been investigated for tissue engineering scaffolds owing to its biodegradability and mechanical strength. Electrospun fibers have large surface area and the fibrous structure provides necessary properties for cell attachment, proliferation, differentiation, and sufficient stiffness. PLLA fibers were irradiated with Kr(+) at an energy of 50 keV with fluences of 1 x 10(13), 1 x 10(14), and 1 x 10(15) ions/cm(2) to improve cell affinity. Morphological change was observed by scanning electron microscopy (SEM). Surface properties were measured by FT-IR-ATR and Raman spectroscopy. L929 cell attachment to Kr(+)-irradiated fibers was evaluated. After the irradiation, the average fiber diameter decreased with high fluence. From the results of the surface analyses, the original chemical bonds were broken and new carbon structures were induced. L929 cell attachment was dramatically improved compared with non-irradiated fibers. Thus, ion-beam irradiated fibers are suitable for tissue engineering scaffolds. This technique is expected to be useful in repairing defects, such as those in nerve, vascular, and liver, in regenerative medicine. (C) 2011 Elsevier B.V. All rights reserved.