TEM images of the CNTs and RACNTs (Fig. 2a–d) were obtained using two types of CCD cameras. A Gatan ES 500W CCD camera was used to acquire the image of the original CNTs (Fig. 2a) and the RACNTs (Fig. 2b). The CNTs were evolved in BSA capsules formed by the interconnection between the BSA amine groups, using glutaraldehyde as a cross-linker. The reaction resulted in imines that were reduced to amines using sodium borohydride.This procedure was necessary to give stability to the BSA layer, since imines are very labile functions.