This paper presents a comparison between the effectivity of 2 different polymer nanofiber modification methods. Poly(styrene-co-maleic anhydride) (SMA) was bulk-modified before electrospinning and SMA nanofibers were surface-modified after electrospinning with identical chemical moieties. These nanofibrous mats, prepared using different synthetic routes, were compared in their use as affinity membranes for micro-organisms, specifically BCG. Characterization of the modified poly(styrene-co-maleimide) (SMI) and its modified nanofibers were done using ATR-FTIR, SEM, H-1 NMR and C-13 NMR, and fluorescence microscopy was used to measure the interaction between the micro-organisms (BCG) and the surfaces of the modified polymer nanofibers. The results indicated that the modification method used to prepare the modified polymer nanofibers did not influence the outcome of the affinity studies with regard to the effectivity of the modified nanofibers as a BCG-capturing platform. The modification agent used for the modification of the polymer nanofibers played the most important role and not the method used for the modification. (C) 2013 Elsevier Ltd. All rights reserved.