Sweet home for proteins. Single-walled carbon nanotube (SWNT) film treated with CDI-Tween20 (CT) has been used as a substrate for a BSA-free protein chip. In the absence of BSA, which is conventionally applied as a nonspecific binding inhibitor, protein A, biotinylated BSA, and even small peptide such as 3 × FLAG immobilized on the CT-functionalized SWNT film substrates recognize their respective counterparts, streptavidin, immunoglobulin G, and antiFLAG. with high specificity. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.