A new functionalized L-cysteine surface modified 3D gold brush nanoelectrode assembly BNEE (L-cys/BNEEs) was prepared. The BNEEs consisted of gold nanowires 100 nm in diameter and up to 400 nm in length fabricated by template synthesis in track etched polycarbonate membranes. The nanowires were exposed by controlled chemical etching of the membrane and were then modified by coating L-cys on the surface of the exposed gold nanowires. The morphology of the BNEEs was imaged by scanning electron microscopy and the real active area of BNEEs was determined by electrochemical impedance spectroscopy. The redox of daunorubicine (DNR) at the L-cys/BNEEs exhibited absorption-controlled characteristics and higher current activity than that at L-cys surface modified 2D disk NEEs (L-cys/DNEEs). The square wave voltammetry technique was employed to detect DNR. The detection limit was 1.0 x 10(-8) M (s/n = 3). The linear detection concentration range of DNR was from 2.5 x 10(-8) to 4.0 x 10(-7) M. (C) 2008 Elsevier Ltd. All rights reserved.