A novel strategy to prepare thick nanofibrous scaffolds with controlled pore size and graded porosity by electrospinning was developed. Taking advantage of the self-assembling properties of bimodal nanofibers, it was possible to grow columns of pores with mm height. The use of a honeycomb microstructured collector allows the control of the pore diameter from 80 to 360 mu m. With increasing sample thickness, the columns of pores begin to merge creating a gradient in pore diameter of up to several hundreds of microns. These scaffolds should be ideal for tissue engineering applications. (C) 2014 Elsevier B.V. All rights reserved.