In this study, DNA strand displacement is utilized to control the aggregation of DNA/gold nanoparticles (AuNPs) based on circular DNA, in which DNA/AuNP conjugates are captured and released by adding different DNA signal strands. Using this strategy, single DNA/nanoparticle building blocks are capable of assembling into complex structures of two and three circular DNA/nanoparticles. The existence of these structures is demonstrated by gel electrophoresis and transmission electron microscopy (TEM) analysis. This advance has potential applications in controlling, transporting and detecting DNA/AuNP conjugates with subsequent manipulation of the structure and function of these assemblies. (C) 2013 Elsevier Inc. All rights reserved.