Detection of DNA using a novel parallel-motif DNA triplex system and graphene–mesoporous silica–gold nanoparticle hybrids. (A) Schematic procedure for the synthesis of graphene–mesoporous silica–gold nanosheets. (B) Illustration of the procedure for preparing the electrochemical sensing interface. (C) The procedure of strand-displacement DNA polymerization amplification and parallel-motif DNA triplex amplification. (D) TEM image of graphene–mesoporous silica hybrids. (E) The differential pulse voltammetric response to target DNA with different concentrations: (a) 0 M, (b) 10−14 M, (c) 10−13 M, (d) 10−12 M, (e) 10−11 M, (f) 10−10 M, and (g) 10−9 M. (F) The effect of probe currents on different concentrations of target DNA (from 10−14 to 10−9 M). Inset: A good linear detection range from 10−14 to 10−10 M was obtained. Reprinted with permission from ref 146. Copyright 2011 Elsevier.