Single-walled carbon nanotubes (SWNTs) were dissolved in aqueous solutions of three different RNAs, poly(A), poly(C) and poly(G). The so-called layer-by-layer technique was applied to fabricate a thin film from RNA-dissolved SWNT solutions on a substrate. Scanning electron microscopy and UV-Vis-near IR and Raman spectroscopies revealed that the films were constituted of the RNAs and SWNTs. No.such multilayer films were obtained when poly(A) was used instead of poly(C), indicating the importance of complementary base pairing between nucleic bases G and C for the formation of the films on the substrate. (c) 2005 Elsevier B.V. All rights reserved.